Keywords: epilepsy; handicap; epilepsy surgery; quality of life; health status. Abbreviations: ... individual (Dodrill et al., 1980; Chaplin et al., 1990; Collings,. 1990 ...
Brain (1998), 121, 317–343
The subjective handicap of epilepsy A new approach to measuring treatment outcome M. F. O’Donoghue, J. S. Duncan and J. W. A. S. Sander Epilepsy Research Group, The Institute of Neurology, Queen Square, London, UK
Correspondence to: Dr M. F. O’Donoghue, Epilepsy Research Group, The Institute of Neurology, Queen Square, London WC1N 3BG, UK
Summary It is now widely acknowledged that the impact of epilepsy on the individual extends beyond the occurrence of seizures, and that there is a need for outcome measures sensitive to these consequences. Until now these instruments have largely been developed within a ‘quality of life’ framework. The technical and conceptual difficulties that arise with measuring quality of life have led us to develop a more focused measurement model, the ‘Subjective Handicap of Epilepsy’ (SHE) scale, based on the World Health Organization’s concept of handicap. The scale contains 32 items in six subscales: ‘Work and activities’ (eight items), ‘Social and personal’ (four items), ‘Self-perception’ (five items), ‘Physical’ (four items), ‘Life-satisfaction’ (four items) and a ‘Change’ scale (seven items); and it takes on average ,10 min to complete. The scale’s test–retest reliability was found to be satisfactory (intra-class correlation coefficient was 0.8–0.9 in 110 subjects). The test–retest interval (24 h to 8 weeks) had no influence on the reliability. The reliability
was also not affected by minor recent fluctuations in seizure frequency. The internal consistency of the scales was 0.8– 0.9 (Cronbach’s α). The construct validity of the scale was examined in a sample of 287 clinic attendees at a university neurology clinic in the UK. The scales were highly sensitive to the handicapping effects of increasing seizure frequency, employment status, the impact of epilepsy on career choice and the subject’s own opinion as to the major determinant of their quality of life. The scales were also sensitive, retrospectively, to the benefits of successful epilepsy surgery in a cohort of 105 patients. Scales focusing specifically on handicap were more sensitive to group differences in seizure frequency in the clinic population, and to outcome after epilepsy surgery, than the ‘Life-satisfaction’ scale and the Epilepsy Surgery Inventory 55 (ESI-55) scales. This supports the contention that measuring ‘subjective handicap’ may be a more sensitive, and more useful, approach to assessing the impact of interventions on the long-term consequences of epilepsy than current methods.
Keywords: epilepsy; handicap; epilepsy surgery; quality of life; health status Abbreviations: ESI-55 5 Epilepsy Surgery Inventory 55; ICIDH 5 International classification of impairments, disabilities and handicaps (WHO); SF-36 5 short form health survey of Ware and Sherbourne (1992); SHE 5 Subjective Handicap of Epilepsy
Introduction It is now widely recognized that the consequences of having epilepsy go well beyond the occurrence of seizures (Hermann, 1992; Jacoby et al., 1996). In recent years a number of investigators have explored the effects of epilepsy on the individual (Dodrill et al., 1980; Chaplin et al., 1990; Collings, 1990; Vickrey et al., 1992; Baker et al., 1993, 1994; Jacoby et al., 1993; Devinsky et al., 1995). Three outcome measures have been developed within a quality-of-life ‘model’; the Epilepsy Surgery Inventory 55 (ESI-55) (Vickrey et al., 1992), the closely related Quality of Life in Epilepsy scales (Devinsky et al., 1995), and the Liverpool scales (Baker © Oxford University Press 1998
et al., 1993, 1994; Jacoby et al., 1993). These studies have revealed that epilepsy has a major impact on employment, social life and the sense of well-being of people with epilepsy. Other studies have highlighted that stigmatization, a sense of ‘loss of control’, fear of seizures, social isolation and emotional difficulties can be important problems for people with epilepsy (Arntson et al., 1986; Dell, 1986; Mittan, 1986; Thompson and Oxley, 1988; Hermann and Wyler, 1989; Antonak and Livneh, 1992; Baker et al., 1996). The most important factor determining the self-reported quality of life appears to be the degree of seizure control (Jacoby et al.,
318
O’Donoghue et al.
1996). People with well-controlled epilepsy typically report few psychosocial problems (Trostle et al., 1989; Jacoby et al., 1992). However, in spite of the interest in the psychosocial impact of epilepsy, there have been few attempts to assess the effectiveness of interventions on the quality of life of people with epilepsy using validated instruments in longterm, controlled, investigations. Existing studies have either been of short duration, or have used retrospective uncontrolled designs. One recent placebo-controlled trial of lamotrigine, which did include quality-of-life measurements (Smith et al., 1993), involved only 18 weeks of active treatment, and it used ‘happiness’ as a measure of quality of life. Retrospective studies of epilepsy surgery have suggested that relief of seizures is associated with improved quality of life (Vickrey et al., 1992; Guldvog, 1994) and longitudinal observational studies have come to similar conclusions (Taylor and Falconer, 1968). The benefits of rehabilitation have also been assessed, though not with validated instruments (Fraser et al., 1983; Beran et al., 1987). A number of methodological difficulties arise when qualityof-life models are applied as outcome measures in epilepsy. The first problem is defining the scope of ‘quality of life’. As many factors potentially affect a person’s quality of life, the content of scales has typically been restricted to ‘healthrelated quality of life’. However, defining the boundaries of ‘health-related’ remains problematic. For example, is ‘underemployment’ (being in a type of employment that does not use your qualifications or experience) in someone with controlled epilepsy a health problem? Without a detailed understanding of the typical social consequences of epilepsy, the term ‘health-related’ would seem unhelpful in defining what is to be measured. Secondly, if a quality-of-life model were to be chosen as a main outcome measure, difficult decisions may arise over what adjustment is made for comorbidity or life-events, which may themselves have a profound influence on quality of life. These issues are particularly pertinent if generic quality-of-life scales (as opposed to disease specific scales) are used as they are generally less sensitive to change in interventions on special groups (Patrick and Deyo, 1989), and intuitively they would seem to be more sensitive to non-specific effects. Thirdly, quality-of-life models typically consist of a mixture of physical symptoms (e.g. pain or fatigue), assessments of emotional state (e.g. happiness, anxiety and depression scales) and aspects of occupational or social functioning. Treating these disparate consequences of disease within a single framework causes difficulties. The time course over which symptoms, as opposed to social functioning, are likely to improve are very different. The causal mechanisms and, more importantly, the appropriate interventions at the various levels of disease consequence are quite different (Wade, 1992). In a review of health status measurement McDowell and Newell (1987) have argued that ‘health indices should measure a specific and defined aspect of health, generally defined in terms of a specific concept or theory’ (1987). Thus, although the notion of ‘health-related quality of life’
is a helpful organizing concept for bringing together the physical, psychological, functional and social effects of disease, its very complexity suggests that it may be helpful, when trying to understand the impact of therapeutic interventions, to focus on different ‘levels’ separately. Before the recent rise in interest in the quality of life, the World Health Organization had already developed a framework for the consequences of a disease on an individual in its ‘International classification of impairments, disabilities and handicaps’ (ICIDH) (World Health Organization, 1980). Impairments are defined as the effects of disease at an organ or system level (typically symptoms and signs), whereas disabilities are the impact on the ability to carry out normal ‘activities’ (such as walking), and handicap is the disadvantage, as a consequence of ill health, that prevents an individual from living out a role in society that most people would consider normal or desirable (e.g. to work or be a parent). The ICIDH is, however, a classification and not a measuring instrument. In the current version it defines six dimensions of handicap; mobility, orientation, physical independence, occupation, social integration and economic self-sufficiency, and there are nine levels of severity for each. A six-item generic scale, which closely follows this structure, the London handicap scale, has recently been developed (Harwood et al., 1994). Handicap can, theoretically, be further divided into ‘objective’ and ‘subjective’ handicaps. Although the WHO classification does not make this distinction, recent critiques of the ICIDH have proposed that this would be a useful perspective (Peters, 1995). Objective handicaps are limitations in those roles that society regards as ‘the norm’ (e.g. holding down a job, driving, having a spouse and children and having leisure pursuits). As such, the presence or absence of an objective handicap is easy to measure, but does not take into account a patient’s perspective and imposes a societal standard. Subjective handicap is the patient’s own assessment of whether they feel handicapped in these domains. Most of the consequences of epilepsy operate at the level of handicap, many of these being directly imposed on the patient by society (e.g. occupational and driving restrictions, and stigmatization). We have sought to develop a model of subjective handicap as it applies to epilepsy. We have not been constrained by the taxonomy of the ICIDH, but instead have used its central ideas to create an instrument. The primary purpose of the measure will be to assess the long-term impact of medical, psychosocial and surgical interventions on the handicap associated with epilepsy. In this paper, the development, reliability and validation of the ‘Subjective Handicap of Epilepsy’ (SHE) scale is reported.
Methods Development and piloting of the scale A review of the psychosocial literature on epilepsy was carried out to identify the key problems that affect the lives
The subjective handicap of epilepsy
319
Table 1 Core domains and specific constructs used to create the SHE scale Domains of handicap
Specific constructs within each domain
Work and activity
Difficulties in obtaining and maintaining employment Being in employment which is not one’s first choice Problems at work due to seizures and medication Travelling and driving Alterations to daily routine due to seizures or medication Effect of epilepsy on leisure and recreation Difficulties secondary to ‘revealing’ epilepsy Alteration in the development of socialization due to childhood epilepsy Alteration in relationship with partner and friends due to epilepsy Social limitations due to travelling and economic constraints Sexual life Stigmatization Feeling of not being in control of one’s future, Fear of seizures leading to injury or death Fear of seizures in public Seizure-related injuries and symptoms Subjective effect of medication on well-being Happiness with one’s work, leisure, and social life Self-reported change across all domains
Social and personal life
Feelings about oneself
Physical Life-satisfaction Change
of people with epilepsy. This was supplemented by ~100 open interviews with people attending a tertiary referral clinic to further define the content of the measure. In addition, the ‘expert opinion’ of specialists in neuropsychology, social work, health status measurement and neurology at the National Hospital for Neurology and Neurosurgery (London), a national referral centre for epilepsy in the UK, was obtained to highlight potential areas of interest. The available qualityof-life scales for epilepsy (Dodrill et al., 1980; Vickrey et al., 1992; Baker et al., 1993, 1994; Jacoby et al., 1993; Devinsky et al., 1995) were also reviewed. This process suggested a number of core problems that ‘handicap’ people with epilepsy: (i) work-related handicaps, which apply also to people in education and training, as well as the effect of epilepsy on other ‘daily activities’; (ii) social and personal life difficulties; (iii) feelings about oneself with epilepsy; and (iv) the subjective physical consequences of epilepsy. These concepts could be further broken down to more specific handicaps (Table 1). The ‘Physical’ scale is, strictly speaking, a mixture of symptoms and disabilities. However, the consistency with which complaints of this nature were reported to create difficulties with ‘role activities’ suggested that it would be appropriate to handle these within the handicap scale. These concepts were then used to derive potential questions. In addition, it was thought that it would be helpful to measure an overall ‘Life-satisfaction’ dimension indicating how happy a person is with various aspects of his/ her life. A ‘Change’ scale was also created to measure self perceived improvement or worsening across dimensions. The time frame for the scale items was ‘the last 6 months’, apart from the ‘Change’ scale which was with respect to ‘the last year’ (because it was envisaged that the scale would be used 1 year after an intervention). One feature of the SHE scale is that the ‘Work and activity’ scale comprises three, mutually exclusive, alternative subscales; the respondent is asked to
complete the scale appropriate to their main activity. This was done because, during the early development of the measure, it was found that subjects had difficulty completing the ESI-55 ‘role’ items, in which ‘work or activities’ were treated as one concept, and this problem led to missing values or ‘guessing’ responses. Accordingly, the three ‘Work and activity’ scales (for those in employment, for those in education or training, and for those not in work) differ slightly in question phrasing and item content, to make them specifically relevant to the main activity. Once the key areas had been defined, ~50 items were presented, for assessment of relevance and intelligibility, to people with epilepsy attending a tertiary referral clinic. Questions were adapted, added and deleted on the qualitative evidence of these interviews. A pilot version was administered to 30 members of an epilepsy self-help group, and a revised version to 30 post-surgical patients for a preliminary assessment of reliability, data quality and content validity. The final selection of items (see Appendix 1) was based on qualitative data (i.e. that the questions appeared to the authors to have face and content validity during extensive testing on patients) rather than on statistical grounds. The detailed statistical evaluation of the final scale is the subject of the study presented here.
SHE scale content and scoring The scale contains 32 items in six subscales: (i) ‘Work and activity’ (eight items), (ii) ‘Social and personal’ (four items), (iii) ‘Physical’ (four items), (iv) ‘Self-perception’ (five items), (v) ‘Life-satisfaction’ (four items) and (vi) ‘Change’ (seven items). One item on ‘Control of epilepsy’ was not included in the study on post-surgical patients). Scoring is on a Likert scale (1–5 for each item). Item scores are then summed, and the subscale score is linearly transformed onto a 0–100 scale,
320
O’Donoghue et al. Table 2 Scale names and content of the ESI-55 ESI-55 scale name
Content
Physical function Role limitation—physical health Role limitation—emotional health Cognitive function Role limitation—memory Social function Emotional well-being (mental health) Energy and fatigue Pain Health perceptions Overall quality of life Global change
Physical disabilities (largely mobility) Activities limited by physical health Activities limited by mental health Memory and thinking Activities limited by memory problems Limitations in social functioning Anxiety and depression items Energy and fatigue Pain Perception of one’s own health Two visual analogue scales Single global change item
with zero indicating worst handicap and 100 least handicap (or most satisfaction). This scoring was chosen so that improvement on all scales would be in a similar direction, and so that the metric was comparable with the SF-36 (a short form health survey; Ware and Sherbourne, 1992), ESI55 and the Quality of Life in Epilepsy scales (Devinsky et al., 1995). On the ‘Change’ scale, 50 5 no change, 0 5 ‘much worse’ and 100 5 ‘much better’.
Other scales used in the study The ESI-55 (Vickrey et al., 1992) contains 11 scales assessing a wide range of quality-of-life domains. It consists of the SF-36 health survey (Ware and Sherbourne, 1992), a widely used generic health status measure tapping eight health concepts, together with five new items on cognitive function, a five-item measure of role limitations due to memory problems, additional items in the role-functioning and healthperception scales and two overall visual analogue quality-oflife scales. Three summary scales measuring physical health, mental health and role functioning can be calculated using weighted sums of the various subscales. The ESI-55 scale names and brief explanation are shown in Table 2.
Sampling and questionnaire administration The scale was administered to two populations: (i) ‘ Group A’, patients attending the epilepsy service of the National Hospital for Neurology and Neurosurgery (London) and (ii) ‘Group B’, a cohort of consecutive patients who had undergone surgical treatment for epilepsy in the last 10 years at the National Hospital for Neurology and Neurosurgery (London). Group A was drawn from two sources. First, a consecutive sample of 183 patients with definite epilepsy (two or more seizures), without learning disability, who had attended the epilepsy follow-up clinic of two specialists in epilepsy. The index visit had been ù1 year before the questionnaire administration so that newly diagnosed cases of epilepsy were not sent a questionnaire. Group A also included 191 consecutive patients referred for video-EEG
telemetry for assessment for epilepsy surgery. Patients with learning disability (IQ ,70) were not enrolled. Group B was derived from a cohort of 129 consecutive patients who had undergone surgical treatment for epilepsy between 1986 and 1993 at the National Hospital for Neurology and Neurosurgery (London). One patient had died of a seizure-related death 6 months post-surgery and three had moved abroad, leaving 125 available for the study with ù6 months follow-up. Clinical details for all subjects were reviewed from the hospital case records to confirm demographic details, diagnosis, seizure classification and recent seizure frequency. A booklet containing the SHE scale, the hospital anxiety and depression scale (Zigmond and Snaith, 1983), demographic and seizure-related questions, open-ended quality-of-life items and ESI-55, in that order, was mailed to all subjects. A single reminder was sent ~6 weeks after the first mailing. Missing values for scale items were interpolated if ù75% of any scale had been completed, otherwise the subscale was described as ‘missing’. The only exception to this rule was items on the ‘Change’ scale which were defaulted to the value of ‘the same’ if missing. These are a more stringent missing value criteria than has been customary in other epilepsy scales (Vickrey et al., 1992). The following demographic and seizure-related information was also requested: years of schooling and educational achievements, employment and marital status, age of onset of epilepsy, current seizure types and frequency, and any additional disabilities or co-morbidities. Current seizure frequency was mainly determined using information from the questionnaire, which requested seizure-frequency data for generalized tonic– clonic seizures, absences (i.e. absence seizures), simple partial seizures and complex partial seizures; each item was accompanied by a vignette of a typical seizure. The case records were also examined to corroborate the approximate seizure frequency. If the self-reported classification was correct the self-reported frequency of each type was used. If there was a conflict in reported types, absence seizures and complex partial seizures were collapsed into complex partial seizures for those with localization-related epilepsies, and
The subjective handicap of epilepsy absence seizures and complex partial seizures were collapsed into absence seizures in those with idiopathic generalized epilepsies. Myoclonic seizures were coded as simple partial seizures. A number of open-ended quality-of-life questions were also included.
Plan of analysis Scaling properties of the SHE scale The response rate was calculated as the percentage of replies with analysable data on the SHE scale. Data quality was assessed using the percentage of missing values for each item (whether eventually interpolated or not). Respondent burden was assessed by timing 40 patients while they completed the scale in front of the investigator (during the test–retest studies) without assistance or time pressure. These 40 subjects were derived from the cohort of 110 subjects used in the reliability analysis. They were selected because they were available for testing either during a period of inpatient assessment or after an out-patient visit. ‘Debriefing’ after SHE scale completion was used in these patients, to identify items that caused comprehension problems. Means and distributions of the subscales were examined for normality and for ceiling and floor effects. The means and standard deviations of the individual items were inspected to ensure approximate equivalence, allowing the subscale totals to be derived from unweighted item scores. The acceptability of placement of individual items in their hypothesized subscales was assessed by ensuring that the correlation between an item and the subscale total with the direct effect of the item removed (Noruo¨is, 1990) (the ‘corrected item– total’ correlation) was ù0.4 for each item. Furthermore, multi-trait scaling analysis was performed to assess whether each item was correlated more highly with its own subscale than with all other subscales. This was examined by comparing the median ‘corrected item–total’ correlation of all items within one subscale with the median correlation of an item with all other scales. The former should exceed the latter if the items are correctly scaled. Finally, ‘Scaling success’ was calculated, using the method adopted by Wagner (Wagner et al., 1995). The percentage of ‘corrected item– total’ correlations that exceed (derived from a Fisher’s Ztransformation; see Altman and Gardner, 1989) ‘item–other total’ correlations by two standard errors indicates whether all items are correctly placed. The optimum value is 100%.
Reliability analysis of the SHE scale
Internal consistency of the subscales, using Cronbach’s α (Cronbach, 1951), was evaluated for all subscales in the entire population, and a subsidiary analysis was carried out for respondents on the three alternative versions of the ‘Work and activity’ subscales (in work, in education and not in work), to ensure that the different versions of this subscale were equivalently reliable.
321
The test–retest reliability of the SHE subscales was also examined in 110 subjects. Three test–retest intervals were used. Twenty-three respondents were retested after 24 h (both times in the presence of the investigator), 24 subjects after 1 week (once in the presence of the investigator and once by mail) and 63 subjects after a 4–8-week interval (both tests by mail). Use of the three intervals, allowed the hypothesis that the reliability would depend on the time interval to be tested. If the reliability was much greater at a short time interval this would suggest that the test–retest investigation was contaminated by simple recall of the previous response rather than measurement of underlying ‘handicap’. In addition, an item asking whether there had been a ‘recent worsening of epilepsy or general health’ was given to the 63 respondents at the longest retest interval, to assess the sensitivity to recent health status change. The reliability analysis was performed using an intra-class correlation coefficient, assuming a two-way random effects analysis of variance model. For the rare occasions when a two-way model led to negative variance estimates, ‘time’ (the effect of retest) was dropped from the model, and a one-way analysis performed. An estimate of the lower confidence interval for the intra-class correlation coefficient was calculated using the approximation developed by Fleiss and Schrout (1978). The reliability was also expressed, following the work of Bland and Altman (1986), as the mean test– retest score difference (second minus first) to estimate the ‘bias’ and the repeatability coefficient (1.96 times the standard deviation of the differences). This coefficient, used by the British Standards Institute (1979) as a measure of the reliability of scientific measurements, indicates between which values (in scale points) 95% of repeat values should lie. There is disagreement in the literature whether the intraclass correlation coefficient or the Bland and Altman method is the most appropriate index of reliability (Johnson, 1994; Streiner and Norman, 1995). The debate turns on whether it is helpful to have a reliability coefficient that depends on the sample variance. For the benefit of users of the SHE scale, both are included. It must be remembered that the degree of scale reliability that is acceptable to an investigator ultimately depends on the purpose to which the scale is put.
Construct validity of the SHE scale Evidence for construct validity of the scale was obtained through four investigations. First, an examination of the mean scores on the SHE scale in subgroups of the clinic attendees sample (group A), when divided by factors such as seizure frequency and employment status. Secondly, the sensitivity of the SHE scale to differences in seizure outcome after epilepsy surgery (group B) was investigated retrospectively. Thirdly, a correlation analysis of scores on the SHE scale and the ESI-55 in the entire dataset was performed. Lastly, a factor analysis was used to provide evidence for the proposed dimensionality of the scale.
322
O’Donoghue et al.
Specific hypotheses investigated The effect of seizure frequency on SHE scale scores.
The effect of employment and other factors on SHE scale scores. A second test of validity was a planned
The first test of validity of the SHE scale was done using the ‘known groups technique’. With this method, the mean scale scores are compared for groups of subjects who are hypothesized to differ in the attribute under investigation (on the basis of theory or prior investigations). If score distributions are in accord with predictions, the investigation can be said to provide validatory evidence for the instrument. In this case it was hypothesized, on the basis of many previous studies (Trostle et al., 1989; Jacoby, 1992, 1995; Jacoby et al., 1993), that the degree of handicap would be related to current seizure frequency for both groups A and B. For the clinic population, the overall seizure frequency was split into four groups: (i) seizure-free for one or more years; (ii) less than one seizure per month (complex partial seizures, generalized tonic–clonic seizures or absence seizures) or only simple partial seizures; (iii) one to four seizures per month (complex partial seizures, generalized tonic–clonic seizures or absence seizures); (iv) more than one seizure per week (complex partial seizures, generalized tonic–clonic seizures or absence seizures). For the postsurgical population the seizure outcome was classified into: (i) seizure-free for 1 year (or seizure-free since the operation if the post-operative duration was between 6 months and 1 year); (ii) simple partial seizures only; (iii) complex partial seizures or generalized tonic–clonic seizures (less than one seizure per month); (iv) one or more seizures per month. The latter classification was used so that the specific effect of simple partial seizures could be examined. The statistical analysis was performed using planned comparisons, followed by post hoc analyses controlling the accepted significance level for multiple comparisons. The planned comparisons in the clinic sample were the mean scale scores of those: (i) seizure-free versus not seizure-free, (ii) with auras or rare seizures versus a greater number of seizures and (iii) those with one to four seizures per month versus more frequent seizures. These three comparisons were carried out using the Helmert system of orthogonal contrasts (Hand and Taylor, 1987), which allows for a complete partition of the variance, and does not require adjustment of the significance level. For the post-surgical population, the comparisons were: (i) seizure-free versus not seizure-free, (ii) auras versus all other seizures and (iii) rare seizures (,12 per year) versus regular seizures. The sample size of the aura and rare seizure groups were relatively small; however, tests of homogeneity of variance were not significant, and therefore an ANOVA (analysis of variance) was considered to be appropriate. Next, trend analyses of scale scores were performed using orthogonal polynomial contrasts to see if scores were linearly related to seizure-frequency category. For each of these analyses the scores on the ESI-55 scales were also examined. Finally, the data were explored using post hoc analyses with the Student–Newman–Keuls procedure (Norusˇis, 1990).
analysis of subscale scores on responses to three additional questions that were postulated to relate to handicap. First, the effect of employment status was examined. This was categorized into full-time/part-time compared with those subjects either unemployed or on disability benefit (students, homemakers and those retired were not analysed as we had no a priori hypothesis as to their ‘average subjective handicap’). Secondly, the scores according to the response to the question whether ‘epilepsy had affected your choice of education, training, job or career’. Finally, scores were compared by response to an additional single item that asked ‘in the last year what has affected your quality of life more overall—epilepsy or other changes?’. It was hypothesized that ‘subjective handicap of epilepsy’ would be higher in those people who perceived their quality of life was primarily determined by epilepsy and in those who felt that epilepsy had affected their choice of main activity. These two questions were used because they were thought to be able to pick out subjects whose lives had specifically been affected by the consequences of epilepsy rather than other life events, and hence be helpful in demonstrating that the scale measured disease-specific handicap.
Correlational and factor analysis. Scores on the SHE scales and the ESI-55 subscales in the entire dataset were correlated. It was postulated that the SHE scales would each correlate best with the counterpart in the ESI-55 that measured a related construct (e.g. ESI-55 ‘Role’ scales and the SHE ‘Work and activity’ scale). The dimensionality of the scale was explored using factor analysis. The suitability of the dataset for factor analysis was first checked by inspecting the correlation matrix for the percentage of correlations which were .0.3, checking the approximate normality of the variables, and ensuring that there were .10 times as many cases as items. Finally, sampling adequacy was tested with the Kaiser–Meyer–Olkin statistic (Noruo¨is, 1990). The entire dataset was then subjected to a principle components analysis, selecting the number of factors with Catell’s scree test, (Cattell, 1966) followed by orthogonal (varimax) and oblique (oblimin) (Noruo¨is, 1990) rotations to extract factors underlying the scale. Results Characteristics of the study population The response rate in the clinic sample (group A) was 77%, and in the post-surgical sample (group B) it was 84%. The clinical characteristics of responders and non-responders are shown for group A in Table 3 and for group B in Table 4. There were no significant differences in age, sex, duration of epilepsy, or seizure frequency between responders and non-responders for group A. In the post-surgical sample males were more common amongst the non-responders, but otherwise no differences were noted.
The subjective handicap of epilepsy
323
Table 3 Clinical and demographic characteristics of responders and non-responders in clinic and video-EEG telemetry sample (group A) Responders (77%, n 5 287)
Non-responders (23%, n 5 87)
Median age (years) Male (%) Median duration of epilepsy (years)
34 46 22
32 54 22
Persons in each syndrome category (%) Localization-related—known aetiology Localization-related—cryptogenic Idiopathic generalized epilepsy Generalized (cryptogenic/symptomatic) Unclassified
59 21 14 2 4
47 22 11 5 15
14 16
25 9
19 51
21 45
Persons in each seizure category (%) Seizure-free for .1 year Simple partial seizures only (or less than one seizure per month) One to four seizures per month More than four seizures per month
Table 4 Clinical and demographic characteristics of responders and non-responders in the post-surgical group (Group B)
Median age (years) Male (%) Median duration post-operation (months) Seizure frequency Persons in each seizure category (%) Seizure-free in the last 12 months Simple partial seizures Rare seizures (less than one per month) More than one seizure per month
Data quality One item (‘Does your epilepsy ever create problems getting on with your partner?’) was answered with an unscored response option (‘I have no partner at the moment’) by 35% of respondents. This item was dropped from the scale subtotals and from all further analyses. Apart from this item, only 0.3% of item responses were coded as missing. Only four questions had .1% missing values (Question 28, 2.5%; Question 8, 2% and Questions 2 and 7, 1%). The median time to complete the questionnaire for 40 respondents was 8 min (range 4–21 min). Interviews after completion of the questionnaire revealed no item causing frequent comprehension problems. No additional area of handicap was consistently mentioned in the open-ended questions.
Descriptive statistics and scaling properties Graphical analyses of the subscales scores revealed that all scales were approximately normally distributed, apart from
Responders (84%, n 5 105)
Non-responders (16%, n 5 20)
31 45 28
33.5 70 32.5
48 11 11 30
44 6 6 44
the ‘Social and personal’ which was moderately negatively skewed. The percentage of respondents scoring at floor values (minimum) or at ceiling (maximum) on each scale (Table 5) was ,5% for all scales except ‘Social and personal’ which had an 18% ceiling effect. For no single scale item did .50% of respondents achieve a similar score, except for the ‘Change’ scale items in which 50–60% indicated no change. The individual item means were within one scale point and standard deviations within half a scale point, indicating that item weighting was unnecessary. The median corrected correlation of each item with its own scale total always exceeded the correlation of that item with other scale totals (Table 5). The percentage of items in each scale in which the ‘corrected item–total’ correlation exceeded by two standard errors ‘item–other total’ correlations is indicated by the ‘scaling success statistic’ in Table 5. The results demonstrated that all scales were appropriately constructed, although two items in the ‘Physical’ scale were also closely related to the ‘Work and activity’ scale.
324
O’Donoghue et al.
Table 5 Descriptive statistics, scaling successes and internal consistency of the SHE scale in 392 patients Subscale
Score at minimum (%)
Score at maximum (%)
Median ‘corrected item–total’ correlation
Median ‘item– other total’ correlation
Scaling success (%)
Cronbach’s α
Work and activity Social and personal Physical Self-perception Life-satisfaction Change
1 1 2 5 1 0
5 18 1 4 2 3
0.69 0.72 0.49 0.69 0.60 0.74
0.48 0.50 0.41 0.49 0.39 0.39
83 100 66 90 96 100
0.88 0.86 0.72 0.87 0.79 0.88
Table 6 Reliability statistics for the six subscales for all 110 subjects Subscale
Mean test–retest difference coefficient (in scale points)
Repeatability correlation (in scale points)
Intra-class coefficient
Work and activity Social and personal Physical Self-perception Life-satisfaction Change
0.6 –1.9 1.8 3.2 –0.2 4.0
24.8 27.6 24.2 26.7 23.0 20.0
0.89 0.86 0.87 0.88 0.86 0.83
Reliability
Cronbach’s α for each scale indicated very satisfactory internal consistency (Table 5). Deletion of no item would have led to a significant increase in α. For the alternative versions of the ‘Work and activity’ scale, α-values were as follows: (i) in employment (n 5 189) α 5 0.85; (ii) in education (n 5 36) α 5 0.87; (iii) not in work (n 5 163) α 5 0.90. This confirms that the alternative versions are equally reliable. Test–retest reliability was carried out on 110 subjects. The overall intra-class correlation coefficients for each scale range from 0.83–0.89 indicating satisfactory reliability (Table 6). As reliability estimates are population dependent, confidence limits were constructed, using the method of Fleiss and Schrout (1978). The lower 95% confidence interval for the intra-class correlation coefficients were in the range 0.76–0.84. The standard error of measurements, which may be used to construct confidence intervals around an individual score, were between eight and 10 points for each SHE scale. The test–retest reliability was examined at three time intervals: 24 h, 1 week and 4–8 weeks (see Table 7). The intra-class correlation coefficient was in very close agreement for each interval and indicated that the scales are equally stable over these intervals. Of the 63 subjects who were retested at 4–8 weeks, 20 indicated a recent worsening in seizures or general health (usually the occurrence of a tonic–clonic seizure). A repeated measures analysis of variance indicated no effect of recent seizures, demonstrating that the scale is not sensitive to minor fluctuations in health. This is important as minor and recent fluctuations in seizure frequency were postulated not to affect handicap. The test–retest reliability was also examined by calculating the mean difference between the first and second rating (bias). There was no bias (Tables 6 and 7), either for all 110 subjects, or when analysed at the three different time
intervals. The sizes of the test–retest differences were plotted against scale scores and this demonstrated that the reliability was equivalent across the range of score values. The repeatability coefficients for each scale indicated that 95% of repeated values for an individual respondent, while stable, lay within ~25 points on the subscale (Table 6). As the standard deviation of scores (for all respondents in group A) on all the subscales was ~25, an effect size of one (change in score/standard deviation of baseline scores) represents a reliable difference for an individual. For group comparisons with a control group the size of a reliable difference is likely to be much less.
Validation studies: cross-sectional clinic and video-EEG telemetry sample (Group A) Effect of seizure frequency on SHE scale scores The first validatory hypothesis to be tested was that subjective handicap, as measured by the scale, would be related to seizure frequency over the last year. Subjects who were seizure-free had the highest scores (least handicap) (Table 8). A series of univariate ANOVA using planned contrasts were carried out examining scale scores by seizure category (Table 8). The first contrast (seizure-free subjects versus those not seizure-free) revealed highly significant differences for four scales (P , 0.0001) and lesser degrees of significance for two scales (‘Social and personal’ and ‘Life-satisfaction’). For the second comparison (those with less than one seizure per month versus those with more frequent seizures), significant differences on all scales (P , 0.001) were evident. The final contrast was between those subjects with one to four seizures per month and those with more frequent seizures, on which only the ‘Physical’ scale demonstrated significant differences. A linear trend of decreasing mean
The subjective handicap of epilepsy
325
Table 7 Reliability statistics for the six subscales at three test–retest time intervals Retest interval, SHE scale Retest at 24 h (n 5 23) Work and activity Social and personal Physical Self-perception Life-satisfaction Change Retest at 1 week (n 5 24) Work and activity Social and personal Physical Self-perception Life-satisfaction Change Retest at 4–8 weeks (n 5 63) Work and activity Social and personal Physical Self-perception Life-satisfaction Change
Mean test–retest difference (in scale points)
Repeatability coefficient (in scale points)
Intra-class correlation coefficient
3.6 –0.6 –1.7 2.6 –0.2 4.0
20.0 30.6 22.6 29.9 20.4 25.9
0.88 0.80 0.84 0.84 0.89 0.81
0.2 –8.3 –0.3 –1.8 –1.3 –1.7
18.6 31.6 21.8 17.2 18.1 18.5
0.92 0.69 0.89 0.96 0.91 0.87
28.2 23.5 25.5 27.9 25.6 18.2
0.83 0.80 0.84 0.85 0.79 0.76
0.48 0.05 3.85 5.2 0.21 1.65
SHE scale score (worsening handicap) across increasing seizure frequency (Table 8) was confirmed using an ANOVA with polynomial contrast for linear trend (P , 0.001) (see Table 8). Lastly, post hoc analysis using the Student– Newman–Keuls procedure for multiple comparisons (at P , 0.05) revealed that for three scales (‘Work and activity’, ‘Physical’ and ‘Self-perception’) it was possible to achieve a clear distinction for all, or all but one, of the potential category comparisons. The least discrimination was found in the ‘Life-satisfaction’ and the ‘Change’ scales. The mean ‘Change’ score of ~50 for all groups, except for those seizurefree, indicated no self-perceived change over the last 12 months. Amongst the seizure-free group, there were patients who had achieved remission within the last 24 months, which probably accounted for the greater mean ‘Change’ score in this subgroup. The ‘Change’ scores for the groups still having seizures were all close to 50 suggesting that no change had occurred in their subjective handicap over the last year. This observation provides evidence that differences in scores on the other five scales represents an underlying trait, rather than recent deterioration.
Effect of seizure frequency on ESI-55 scale scores The mean ESI-55 scores (and 95% confidence interval) for seven of the 11 subscales and the three summary scales in the cross-sectional population with differing seizure frequencies are shown in Table 9. The four subscales for which there were only small, or no significant, differences between the groups (‘Physical function’, ‘Pain’, ‘Energy and fatigue’ and ‘Emotional well-being’) are not shown for
reasons of brevity. Significant differences in the ‘seizure-free versus not seizure-free’ comparison were found for all the ESI-55 subscales shown in Table 9. However, there were only three subscales, and the three summary scales, where significant differences were found in the second comparison (less than one seizure per month versus more frequent seizures). None of the final comparisons (one to four seizures per month versus more than one per week) reached significance. A linear trend in ESI-55 score across seizurefrequency was found for all subscales shown (P , 0.01).
Effect of employment and other factors on SHE scale scores The second set of validatory hypotheses that were tested were the relationships between scale scores and the following: (i) employment status; (ii) the effect of epilepsy on career or job choice and (iii) what factor the subject perceived as the main determinant of their quality of life. We postulated that most scales should indicate that those in work would feel less handicapped. The mean score was significantly greater (less handicapped) for those in employment for all six scales (Table 10). Higher scores were also seen on the ‘Change’ scale for the ‘less handicapped’ groups, but the size of this difference (10 scale points) was less than on the four handicap scales (12–18-point differences), suggesting that the overall differences were not simply accounted for by recent change. In the second analysis, actual employment status was ignored, but subjects were asked whether their epilepsy had
326
O’Donoghue et al.
Table 8 SHE scale scores according to seizure frequency for the clinic and video-EEG telemetry sample (group A) Seizure frequency groups
Mean SHE-scale scores and [95% confidence intervals] Work and activity
Social and personal
Physical
Selfperception
Lifesatisfaction
Change
Seizure-free group (n 5 38) (versus ‘not seizure-free’)†
81**** [76, 86]
78** [71, 85]
68**** [63, 73]
68**** [60, 75]
66* [61, 72]
64**** [59, 68]
SPS or ,1 Sz/month (n 5 47) (versus ù1 Sz/month)†
67**** [62, 73]
77**** [70, 84]
57**** [52, 62]
56**** [50, 63]
65** [59, 71]
55** [51, 59]
1–4 Sz/month (n 5 54) (versus .4 Sz/month)†
51 [46, 56]
63 [56, 69]
48* [43, 53]
43 [37, 49]
55 [49, 61]
49 [45, 52]
.4 Sz/month (n 5 147)
45 [42, 49]
62 [57, 66]
40 [37, 44]
39 [35, 43]
56 [53, 59]
48 [46, 51]
109.4****
19.2****
65.8****
50.1****
14.0***
39.2****
F-ratio for a linear trend in SHE scale across seizure frequency
SPS 5 simple partial seizures, Sz 5 seizure. †Significant differences between mean SHE scores (versus group with more seizures; see details in first column): *(P , 0.05); **(P , 0.01); ***(P , 0.0002); ****(P , 0.0001).
Table 9 ESI-55 subscale and summary scores according to seizure frequency for the clinic and video-EEG telemetry sample (group A) Seizure frequency
Mean ESI-55 scale scores and [95% confidence intervals] Role, Role, Health Social Cognition Role, Quality Mental Physical Role physical emotional percept- function memory of life health health function ions summary summary summary
Seizure-free group (n 5 38) (versus ‘not seizure-free’)†
85*** 82** [78, 91] [74, 90]
72* 87*** 76*** [66, 77] [81, 94] [68, 83]
87** 69** 70** [79, 94] [64, 74] [65, 75]
81** [77, 85]
84*** [77, 89]
SPS or ,1 Sz/month (n 5 47) 73* 68 (versus ù1 Sz/month)† [64, 83] [57, 79]
68 77 69** [63, 72] [69, 85] [63, 76]
73 67**** 66** [64, 82] [62, 71] [62, 71]
75* [69, 80]
72* [65, 79]
1–4 Sz/month (n 5 54) (versus .4 Sz/month)†
59 66 [48, 69] [56, 76]
64 69 61 [59, 69] [62, 76] [55, 67]
67 59 60 [57, 76] [54, 63] [56, 65]
70 [65, 76]
65 [57, 72]
.4 Sz/month (n 5 147)
59 64 [53, 66] [57, 70]
60 70 56 [57, 63] [65, 75] [52, 60]
62 55 58 [56, 68] [53, 58] [55, 60]
67 [63, 70]
62 [58, 67]
F-ratio for a linear trend in ESI-55 across Sz frequency
18.8**** 6.6**
13.4**** 15.2**** 25.4****
16.5**** 25.3**** 20.6****
17.6***
22.5***
SPS 5 simple partial seizures; Sz 5 seizure. †Significant differences between mean ESI-55 scores (versus groups with more seizures; see details in first column): *(P , 0.05); **(P , 0.01); ***(P , 0.001); ****(P , 0.0001).
made a difference to job or career choice. This analysis avoided the assumption that current employment status represented the person’s ideal choice of main activity, as it was noted that 59% of those in work responded that job choice had been affected. In addition, subjects currently not in work could be analysed; of these, 91% responded to this item, and 66% indicated that epilepsy had affected their career or job. Those subjects whose job choice had been affected by epilepsy were more handicapped on all scales (Table 10). In the third analysis subjects were asked ‘What in the last year has affected your quality of life more overall—epilepsy or other changes in your life?’ The hypothesis was that
subjects who felt that epilepsy was the dominant quality-oflife factor, would also be those who felt most ‘handicapped’ by epilepsy. Of the 89% of subjects who responded to this item, 66% indicated that epilepsy had been the dominant factor. The responses were not identical to those to the career question, in that only 74% of subjects who felt epilepsy had affected job choice indicated that epilepsy had been the dominant factor in quality of life, and that 48% of subjects who felt epilepsy had not affected their job, still believed that epilepsy was the determining factor in quality of life. Patients who felt that epilepsy was the dominant factor scored significantly lower on all scales (Table 10).
The subjective handicap of epilepsy
327
Table 10 SHE scale scores for clinic and video-telemetry EEG sample (group A) by employment, effect of epilepsy on career and dominant factor determining quality of life Comparisons
SHE scale scores and [95% confidence intervals] Work and activity
Social and personal
Physical
Selfperception
Lifesatisfaction
Change
62*** [58, 65] 44 [39, 49]
73*** [69, 76] 58 [52, 64]
54*** [51, 57] 39 [34, 44]
51** [47, 55] 39 [34, 45]
64*** [61, 67] 50 [45, 54]
56*** [53, 58] 46 [42, 49]
80*** [76, 84] 61 [58, 65]
57*** [53, 61] 45 [41, 48]
59*** [53, 64] 41 [37, 44]
69*** [66, 73] 54 [51, 57]
56*** [53, 60] 50 [47, 52]
What has most affected your quality of life in the last year? Other changes (n 5 87) 69*** 75*** [65, 74] [70, 79] Epilepsy (n 5 168) 44 59 [41, 47] [55, 63]
57*** [53, 61] 41 [38, 44]
60*** [55, 65] 36 [32, 39]
62* [58, 66] 55 [52, 58]
56*** [53, 59] 48 [46, 50]
Employment status Employed (n 5 138) Unemployed (n 5 88)
Has epilepsy affected choice of education, job, or career? No (n 5 87) 69*** [65, 74] Yes (n 5 174) 48 [45, 51]
All comparisons revealed significant mean SHE scale score differences. *P , 0.005; **P , 0.001; ***P ,0.0001.
Table 11 SHE scale scores for post-surgical group (group B) according to seizure outcome Seizure outcome
Mean SHE scale scores and [95% confidence intervals] Work and activity
Social and personal
Physical
Selfperception
Lifesatisfaction
Change
Seizure-free (n 5 48) (versus ‘not seizure-free’)†
84**** [79, 89]
84* [79, 89]
72**** [67, 77]
78** [72, 84]
71* [66, 76]
78** [72, 84]
Simple partial seizures (n 5 12) (auras versus all other seizures)†
75 [61, 89]
80 [62, 98]
63 [49, 77]
81** [68, 94]
66 [55, 76]
69 [54, 85]
,1 Sz/month (n 5 12) (versus .1 Sz/month)†
71** [56, 86]
78* [63, 92]
57 [47, 66]
66* [51, 81]
65 [50, 80]
66 [50, 82]
.1 Sz/month (n 5 31)
50 [40, 59]
60 [50, 70]
50 [42, 59]
51 [41, 61]
54 [45, 64]
59 [53, 65]
F-ratio for a linear trend in SHE scale across seizure frequency
34.6*****
16.1****
21.2*****
26.7*****
9.4***
12.5****
Sz 5 seizure. †Significant differences between mean SHE scores (versus group with more seizures; see details in first column): *P , 0.05; **P , 0.01; ***P , 0.001; ****P ,0.0001; *****P ,0.00001.
Validation: post-surgical population (group B) Effect of post-surgery seizure frequency on SHE scale scores The first validation hypothesis to be tested in the post-surgical population was that ‘subjective handicap’, as measured by the SHE, would be related to seizure outcome. The highest score (lowest handicap) was obtained by those subjects rendered seizure-free by surgery (Table 11) for all scales except one. The exception was the ‘Self-perception’ scale in which subjects with auras scored non-significantly higher than those who were seizure-free. There was also a trend of
decreasing score by increasing seizure frequency. The planned comparisons revealed significant differences for those subjects who were seizure-free compared with those not seizure-free for all subscales (Table 11). The comparison of auras versus all other seizures was significant for the ‘Selfperception’ (P , 0.01) scale but just failed to reach significance for the ‘Work and activity’ scale. The comparison of rare seizures (less than one per month) versus more frequent seizures was significant for the ‘Work and activity’ and ‘Social and personal’ scales and just failed to achieve significance for the ‘Self-perception’ and ‘Change’ scales. The relatively wide confidence intervals for the two middle
328
O’Donoghue et al.
Table 12 ESI-55 scale and summary scores for post-surgical group according to seizure outcome Seizure outcome
Mean ESI-55 scale scores and [95% confidence intervals] Role, Role, Health Social Cognition Role, Quality Mental Physical Role physical emotional percept- function memory of life health health function ions summary summary summary
Seizure-free (n 5 48) (versus ‘not seizure-free’)†
84* 81** [76, 92] [73, 90]
82** 87** 74 [78, 86] [81, 92] [68, 80]
83 72** 73* [75, 91] [67, 77] [69, 78]
82* [77, 87]
82* [76, 87]
Simple partial seizures (n 5 12) 78 65 (versus more [56, 100][45, 85] frequent seizures)†
86*** 81 75 [78, 94] [72, 89] [59, 91]
87 65 72 [75, 98] [52, 77] [64, 80]
80 [70, 90]
77 [66, 88]
,1 Sz/month (n 5 12) (versus.1 Sz/month)‡
62 48 [39, 85] [22, 75]
72 76 78 [58, 87] [64, 88] [71, 85]
67 60 66 [47, 86] [44, 76] [54, 77]
73 [60, 85]
65 [49, 80]
.1 Sz/month (n 5 31)
69 65 [54, 84] [51, 80]
61 65 66 [53, 69] [54, 76] [56, 76]
74 57 61 [61, 86] [49, 65] [54, 67]
71 [64, 78]
68 [59, 78]
30.2**** 15.1***
4.1
8.4**
8.4**
F-ratio for a linear trend in 5.1 ESI-55 across seizure outcome
5.4
1.2
9.1**
12.3***
Sz 5 seizure. ‡No significant differences. †Significant differences between mean ESI-55 scores (versus groups with more seizures; see details in first column): *(P , 0.05); **(P , 0.01); ***(P , 0.001); ****(P , 0.0001).
outcome categories, due to small sample size, may preclude the detection of differences between these groups. A linear trend of scale scores with outcome category was found for all scales (Table 11).
Effect of post-surgical seizure frequency on ESI55 scale scores Five subscales and three summary scales showed a significant difference in the primary comparison of ‘seizure-free versus not seizure-free’ (Table 12). Only one ESI-55 scale (Health perceptions) detected a difference on the second or third comparisons. A linear trend was found for three of the main scales and all three summary scales.
Effect of employment and other factors on SHE scale scores As in the cross-sectional clinic population, a second set of validatory investigations were carried out based on the response to the three additional questions on (i) employment status, (ii) the effect of epilepsy on career or job choice and (iii) the major determinant of quality of life (epilepsy versus ‘other changes’). Those subjects who were employed had higher scores (less handicap) than those not in work for all scales (P , 0.001) (Table 13). Those subjects who felt their career or job choice (postoperatively) had not been affected scored significantly more highly on all scales except the ‘Change’ scale (P , 0.001). Finally, those subjects who felt that epilepsy was not the dominant factor in their quality of life scored more highly on all scales except the ‘Change’ scale (P , 0.001).
Correlations of SHE scale with the ESI-55 scale For all 392 subjects in the study the correlation of the SHE scale scores with ESI-55 scales are shown in Table 14. Correlations for the SHE scales with the ESI-55 summary scales (not shown) were all about 0.5–0.6. The SHE ‘Work and activity’ scale was moderately strongly correlated with ESI-55 ‘Role, physical’, ‘Health-perception’ and ‘Social functioning’ scales. The SHE ‘Physical’ scale was most closely related to the ESI-55 ‘Energy and fatigue’, ‘Cognition’ and ‘Role, memory’ scales. The SHE ‘Physical’ is not related strongly to the ESI-55 ‘Physical’, as the latter measures chiefly mobility and the former epilepsy and drug-related symptoms. The SHE ‘Social and personal’ scale was most correlated with the ESI-55 ‘Social functioning’ and least correlated with scales to do with physical functioning. The SHE ‘Self-perception’ was best correlated with ESI-55 ‘Health perceptions’, and was also quite closely related to cognitive and mental health scales (ESI-55 ‘Mental health’, ‘Cognitive’, ‘Social functioning’), but was unrelated to mobility (ESI-55 ‘Physical function’). The SHE ‘Life satisfaction’ was highly correlated with the ESI-55 ‘Quality of life’ visual analogue scales and the SHE ‘Change’ scale was correlated with the ESI-55 ‘Change’ scale. These results suggest that relationships that one would expect between the ESI-55 and the SHE scale (those most related in content) are indeed confirmed.
Factor analysis of the SHE scale scores The dataset met all criteria required for an adequate factor analysis. Factor extraction by principle components, followed by orthogonal or oblique rotation, gave comparable results.
The subjective handicap of epilepsy
329
Table 13 SHE scale scores for post surgical group (group B) by post-operative employment status, effect of epilepsy on career choice and the dominant factor determining quality of life Comparisons
Mean SHE scale scores and [95% confidence intervals] Work and activity
Social and personal
Physical
Selfperception
Lifesatisfaction
Change
83*** [76, 89] 56 [47, 65]
86*** [80, 92] 64 [55, 73]
71*** [66, 76] 50 [42, 59]
77** [71, 83] 61 [51, 70]
73*** [68, 79] 53 [45, 60]
77** [72, 83] 60 [52, 67]
Has epilepsy affected choice of education, job or career (post-surgery)? No (n 5 54) 83*** 84* [78, 88] [79, 89] Yes (n 5 34) 58 69 [48, 67] [59, 78]
72*** [68, 77] 51 [44, 59]
79** [74, 85] 60 [51.69]
71* [66, 76] 57 [49, 65]
74 [68, 79] 66 [58, 74]
What has most affected your quality of life in the last year? Other changes (n 5 52) 80*** 84*** [74, 86] [79, 90] Epilepsy (n 5 34) 54 61 [45, 64] [51, 70]
69*** [64, 73] 51 [42, 59]
76*** [71, 82] 53 [44, 63]
68* [63, 73] 55 [47, 63]
71 [65, 77] 65 [59, 71]
Employment status post-surgery Employed (n 5 45) Unemployed (n 5 34)
Significant mean SHE scale score differences: *P , 0.005; **P , 0.001; ***P ,0.0001.
Table 14 Correlation matrix of SHE scale and ESI-55 scales (n 5 392)* SHE scale
Work and activity Physical Social and personal Life-satisfaction Self-perception Change
ESI-55 Scale Physical Role, Role, Energy, Health Social Mental function physical emotional fatigue percept. function health
Cognition Pain
Role, Change Quality memory of life
0.37 0.36 0.32 0.29 0.29 0.27
0.55 0.64 0.49 0.40 0.59 0.41
0.50 0.50 0.40 0.37 0.48 0.37
0.50 0.50 0.38 0.38 0.41 0.39
0.37 0.39 0.33 0.38 0.35 0.30
0.38 0.54 0.32 0.46 0.43 0.40
0.56 0.56 0.49 0.46 0.63 0.41
0.57 0.54 0.56 0.51 0.56 0.42
0.37 0.43 0.46 0.54 0.53 0.42
0.32 0.46 0.35 0.29 0.33 0.23
0.37 0.40 0.21 0.26 0.35 0.59
0.54 0.54 0.47 0.68 0.55 0.58
Percept. 5 perceptions. *P , 0.01 for all correlations.
The six-factor model accounted for 65% of the variance. Table 15 displays the rotated factor matrix, with the loading of the six factors on each item, if the loading is .0.4. Also shown are the subscales in which each subscale was placed, a priori, on the grounds of content validity. Inspection of the matrix reveals that the postulated dimensionality of the SHE scale is very largely confirmed by the factor analysis. The only significant deviation of the factor model from the proposed scale structure is that two items in the ‘Physical’ scale would appear to be closely related to the ‘Work and activity’ scale. The original SHE scale structure has been retained as the content of this scale seemed to have greater face validity.
Discussion The SHE scale contains four scales that measure the handicap associated with epilepsy, from a patient’s perspective. It is postulated that subjective handicap is a medium- to longterm trait, and that only therapies that have a major impact on
the impairment (the seizures), or rehabilitative interventions directed specifically at modifying the causes of handicap, will affect this attribute. In addition, one scale measuring life-satisfaction, in a manner more akin to current qualityof-life scales, and a seven-item global change scale are included. The latter ‘non-handicap’ scales are included so as to maximize the validity of the SHE as a measure of change. If subjective handicap, life-satisfaction and self-perceived change all improve after an intervention, one can be more confident that benefit has arisen. The SHE scale does not purport to be a global health status scale for epilepsy because it does not directly measure mental health, or physical or cognitive disabilities. If these aspects of health need to be measured, multidimensional scales which include these factors (Vickrey et al., 1992; Baker et al., 1993; Devinsky et al., 1995) should be used. Our investigations suggest that the SHE scale is practicable and acceptable to patients, in that an unselected clinic population (apart from those with obvious learning disabilities) were able to complete the scales, on average, in
330
O’Donoghue et al.
Table 15 Factor loading of the rotated factor matrix Item
SHE subscale
Factors and postulated meanings 1 Work
Q1 Q2 Q3 Q14 Q15 Q17 Q18
Work and Work and Work and Work and Work and Physical Physical
activity activity activity activity activity
Q26 Q27 Q28 Q30 Q31 Q32
Change Change Change Change Change Change
Q19 Q20 Q21 Q22 Q23 Q24 Q25
Work and activity Work and activity Self-perception Self-perception Self-perception Self-perception Self-perception
Q8 Q9 Q10 Q11 Q12
Social and personal Social and personal Social and personal Social and personal Life-satisfaction
Q6 Q7 Q13 Q16
Work and activity Life-satisfaction Life-satisfaction Life-satisfaction
Q5 Q4
Physical Physical
2 Change
3 Selfperception
4 Social life
5 Lifesatisfaction
0.66 0.77 0.73 0.67 0.52
0.48
6 Physical
0.69 0.78 0.57 0.65 0.55 0.66 0.71 0.76 0.74 0.63 0.78 0.80 0.79 0.45
0.57 0.63 0.68 0.60 0.70 0.65 0.61
0.40
0.52 0.78 0.58 0.52 0.66 0.52
Question 29 (not used in the surgical sample) was not included in this factor analysis.
,10 min with good data quality. The internal consistency and test–retest reliability were quite high, in that both Cronbach’s α and the intra-class correlation coefficient exceeded, or nearly so, the minimum of 0.8 recommended for scales used in group comparisons (Nunnally and Bernstein, 1993). Furthermore, the scale was not affected by minor fluctuations in seizure control that may occur within a time frame of a few weeks. This is an important property, because if the scale scores had been sensitive to transient changes in physical health (insufficient to affect handicap), this would have confounded the ability to measure the postulated longterm underlying trait ‘subjective handicap’. The values of Cronbach’s α for the alternate versions of the ‘Work and activity’ scales were equivalent, suggesting that the wording changes and the difference in one item had not affected the internal consistency of the scales. As with any scale, it will
be valuable to repeat the reliability estimates in a population outside the developers’ institution. The content validity of the SHE scale is supported by the method of its construction. The review of the literature and available quality-of-life scales, together with the unstructured interviews and expert opinion used to select the items, provided a consistent set of themes. Free text responses to an item requesting ‘Is there anything more you would like to tell us about how epilepsy has affected your quality of life in general?’ produced more details on the concepts used in the SHE scale but no new core ‘handicaps’. An additional two-item scale on sexual functioning was used in the postsurgical group, but not in the cross-sectional population, and it is not part of the scale. Piloting of these two sexual items revealed a 10–20% non-response rate and ‘debriefing’ of some respondents suggested it may be too intrusive in
The subjective handicap of epilepsy contexts in which sexual functioning was not ‘on the agenda’ in the doctor–patient relationship. Construct validity was obtained from several sources. First, the level of handicap was clearly related to the frequency of seizures. This is in keeping with findings in other studies (Jacoby et al., 1993, 1996). All scales detected differences in handicap between subjects who were seizure-free and those not seizure-free, as did all scales in the comparison between subjects with less than one seizure per month and those with more than one. One scale (‘Physical’) detected a difference in the comparison of patients with less than one seizure per week with those with more than one per week, and another scale (‘Work and activities’) just failed to reach significance. This suggests that the scales are highly sensitive to the handicapping effect of increasing seizure frequency, in spite of the fact that seizure frequency is not explicitly part of the content of the scales. One method of expressing the sensitivity of health scales to differences between patient groups (if the groups have an intuitive gradation) is ‘relative efficiency analysis’ (Liang et al., 1985), in which the F-ratio for linear trends across the groups on different scales are compared: the higher the F-ratio the more sensitive the scale. For the SHE scale, the F-ratios (see Table 8) ranged from 109 (‘Work and activity’) to 14.0 (‘Life-satisfaction’). Comparison of F-ratios for a linear trend of the SHE scales with the ESI-55 scales (Table 9) for the ‘Work and activity’related handicaps revealed that the ESI-55 scales were only 25% as sensitive. For social functioning they were comparable. The SHE ‘Physical’ and ‘Self-perception’ do not have direct counterparts in the ESI-55, but were more sensitive than all ESI-55 scales. It is interesting that the scales focusing on handicap were more sensitive than the more conventional ‘Life-satisfaction’ scale. This supports the contention that focusing on specific aspects of outcome is more sensitive than global satisfaction assessments. Two explanations for this are possible. First, patients may adapt over time to limitations in their lives and come to accept, cognitively, as ‘satisfactory’ what previously was unacceptable (de Haes et al., 1992), though if asked specifically about symptoms or feelings, reduced well-being is revealed. Secondly, events not related to health can influence the quality of life and, hence, may limit the sensitivity of the ‘life satisfaction’ scales. Further evidence for construct validity was found in that the SHE scales were sensitive, retrospectively, to the kind of changes in handicap one expects after a major intervention such as successful epilepsy surgery. All scales, especially the more handicap-focused scales detected differences according to seizure outcome. The SHE scales were more sensitive in detecting differences post-surgery than the ESI-55 scales, in that F-ratios for linear trends for the ESI-55 scales (Table 12) were lower than of those SHE scale (Table 11), with the exception of the ‘Health perceptions’ scale which performed well. Interestingly, the ESI-55 ‘Health perceptions’ scale was also found to be the most sensitive in the original publication of Vickrey et al. (1992). The incremental validity of the SHE
331
scales over the ESI-55 scales is because all the SHE scales are focused on the specific effects of epilepsy, whereas many of the ESI-55 items are based on a generic instrument. These findings, taken together, suggest that the SHE scales are more sensitive to the handicapping consequences of epilepsy than the ESI-55 scales. Assuming that people who are seizure-free have less handicap was a reasonable first hypothesis. However, it was felt that the validation of the SHE scale would be more persuasive if it could be shown that the SHE scores were related to handicap-related constructs. Therefore, we examined the scores on a number of other criteria. We demonstrated that people who are objectively handicapped (e.g. unemployed) scored much lower on all of the scales. In addition, people who consider that they are not following their first choice of main activity, even if employed, also scored lower on the SHE scales. Finally, subjects who rated epilepsy as the main determinant of the quality of their life scored significantly lower on all scales. These lines of evidence suggest that the SHE scales are sensitive to the long-term, disease specific consequences of epilepsy. Validity for the grouping of the SHE items into the various scales was provided by the correlation of each item with its own scale total (Table 5). This showed that each item (corrected for the effect of the item itself) was more closely related to its own scale than to the other scales. Further construct validity was sought by correlating the ESI-55 scales and the SHE scales. There were clear relationships between ESI-55 and the SHE scale. The activity-related items (called ‘Role’ in the ESI-55) and social function in both scales correlated highly. The SHE ‘Physical’ (which deals with physical symptoms not mobility) was correlated with the ESI-55 ‘Energy and fatigue’. The SHE ‘Self-perception’ has no direct counterpart in the ESI-55, but did appear to be related to the ESI-55 ‘Health perceptions’ and to mental and social concepts. Though the item content of the two ‘Perception’ scales are different, it appears that both tap into people’s perception of themselves. The SHE ‘Lifesatisfaction’ was more highly correlated with the ESI-55 ‘Quality of life’ scale than any other scale. Though the format of the scales is different (Lickert and visual analogue, respectively) they clearly have a similar content. The SHE and ESI-55 ‘Change’ scales were also highly correlated. The SF-36 survey, which forms the core of the ESI-55, now has a large body of evidence supporting its validity as measure of aspects of health (Ware and Sherbourne, 1992; Jenkinson et al., 1993, 1994; McHorney et al., 1993; Ruta et al., 1994). The fact that several SHE scales are correlated with intuitively appropriate ESI-55 scales further suggests the scale is measuring valid constructs. Finally, the factor analysis demonstrated that the dimensions of the SHE scale that had been postulated at the outset were largely confirmed. Two physical items (‘Injuries’ and ‘Feeling unwell’ were closely associated with the ‘Work and activity’ scale. It may simply be that these two items are sensitive to an underlying ‘severity of epilepsy’ dimension
332
O’Donoghue et al.
which is also strongly related to the overall effect of epilepsy on activities. The original structure was maintained as the face validity of this grouping was superior. It may be asked whether the SHE does really measure ‘handicap’ rather than another related construct. In health services research this type of distinction is usually demonstrated by establishing convergent and discriminant construct validity, that is to say, that the scale correlates highly with measures related to ‘handicap’ but poorly with unrelated constructs. At present no other handicap scale exists in the field of epilepsy with which to provide convergent validity. However, the performance of the SHE scale against indices of objective handicap, such as employment status and career choice (Tables 10 and 13) do indeed suggest that the SHE scale is highly related to handicap. Evidence of discriminant validity is provided by the pattern of the correlations of SHE subscales with ESI-55 subscales (Table 14). For instance, the SHE ‘Social and personal’ scale is most closely related to the ESI-55 social functioning scale, and least to physical mobility (ESI-55 ‘Physical function’), and the SHE ‘Self-perception’ is related to ESI-55 mental health and social constructs rather than mobility. Other relationships appear more complex, as the ‘Work and activity’ scale is related to ‘Role, physical’, ‘Social functioning’ and ‘Cognition’. This is not surprising as handicaps in occupational and social life may have shared causes. Because of the complex interactions between the many consequences of epilepsy, sole reliance (for the purposes of validation) on the relative strengths of correlations (convergent and discriminatory) between constructs was not justified. To provide validatory evidence for the scale, we have focused on groupings of items that made intuitive sense (face and content validity) and on the outcome of hypothesis testing with the scale. It should also be borne in mind that validation is an incremental process rather than an absolute property. Some explanation of the role of SHE scale in the context of the other available scales is required. The ESI-55 has the advantage that it contains the SF-36, and hence comparisons across disease categories can be made, if this is thought to be an essential part of an investigation. However, in the context of outcome studies, it is likely that comparisons of interventions such as epilepsy surgery or rehabilitation with the treatment of other chronic diseases will not frequently be the focus of interest. The more recently developed Quality of Life in Epilepsy-89 instrument shares many of its items with the ESI-55, but has a broader coverage of the social and occupational issues (Devinsky et al., 1995). As no prospective studies with the scale are available, the sensitivity to change remains to be determined. The performance of the new items in the Quality of Life in Epilepsy scale, compared with that of the SHE scale, also remains to be examined. The Liverpool impact scale (Jacoby et al., 1993) is an eightitem instrument, which shares the measurement aims of the SHE scale. Concern about its brevity, and hence sensitivity to the issues we wished to measure, led us to develop a more extensive scale. The impact scale reports a single outcome
variable and thus will not be able to distinguish between different consequences of epilepsy (e.g. social versus occupational). The Washington Psychosocial Inventory was the first measure to be used in epilepsy to assess the broader concerns of people with epilepsy (Dodrill et al., 1980). However, its ‘yes/no’ format of response limits its ability to detect change. Some investigators have pointed out that questionnaires using a standardized set of items do not allow patients to express their own priorities for the outcome of treatment (Kendrick and Trimble, 1994; Selai and Trimble, 1995). Some promising measures have been developed to allow patients to chose the domains to be examined (Guyatt et al., 1987; O’Boyle et al., 1992; Ruta et al., 1996). However, such methods remain complex and may require the presence of a trained investigator. One study, using a self-completed ‘individualized’ scale, reported that only 63% of subjects returned a correctly completed questionnaire (Ruta et al., 1996). It is also unclear how to analyse data from subjects who report at follow-up that their priorities have changed from the baseline. The methodology of the SHE scale is based on the belief that it will principally be applied in controlled group studies. As the content of the SHE scale covers a wide range of issues, important to most people with epilepsy, application of the scale can answer the question whether, on average, the typical handicapping effects of epilepsy are influenced by an intervention. The scale is not designed to make individualized assessments of patients, but further studies of whether physicians find the information helpful at a clinical level would be valuable. The evidence from the use of the Dartmouth COOP Chart method suggests that this type of information can influence clinical practice (Nelson et al., 1987). The data presented cannot be considered an exploration of the handicap of epilepsy in the community as a whole, in view of the current sample being from a specialist clinic. An unselected community sample of active and remitted epilepsy is currently being studied with the SHE scale. Furthermore, there is as yet no data on the responsiveness of the SHE. Longitudinal studies of the effects of epilepsy surgery are on-going in an attempt to assess the SHE’s responsiveness.
Conclusions The SHE scale would appear to be a reliable, valid measure of the long-term consequences of epilepsy. It is also short and ‘user acceptable’. We recommend that it is particularly suitable for longitudinal investigations into the effectiveness of interventions designed to help overcome the serious handicaps faced by people with chronic epilepsy.
Acknowledgements We wish to thank Professor Simon Shorvon, Dr David Fish and Mr W. Harkness for allowing us to study patients under
The subjective handicap of epilepsy their care, also Professor David Chadwick and Dr Gus Baker for helpful discussion and permission to use the Liverpool quality-of-life scales, and Drs Pamela Thompson and Crispin Jenkinson, Caroline Selai, Alice Hanscomb, Laura Hill and Claire Gatt for help during the development of the SHE scale. We especially wish to thank the many subjects involved in the study for their co-operation. The research was funded by the National Society for Epilepsy (UK).
References Altman DG, Gardner MJ. Calculating confidence intervals for regression and correlation. In: Gardner MJ, Altman DG, editors. Statistics with confidence. London: British Medical Journal Publications, 1989: 34–49. Antonak RF, Livneh H. A review of research on psychosocial adjustment to impairment among persons with epilepsy. J Epilepsy 1992; 5: 194–205. Arntson P, Droge D, Norton R, Murray E. The perceived psychosocial consequences of having epilepsy. In: Whitman S, Hermann BP, editors. Psychopathology in epilepsy: social dimensions. New York: Oxford University Press, 1986: 143–61. Baker GA, Smith DF, Dewey M, Jacoby A, Chadwick DW. The initial development of a health-related quality of life model as an outcome measure in epilepsy. Epilepsy Res 1993; 16: 65–81. Baker GA, Jacoby A, Smith DF, Dewey ME, Chadwick DW. Development of a novel scale to assess life fulfillment as part of the further refinement of a quality-of-life model for epilepsy. Epilepsia 1994; 35: 591–6. Baker GA, Jacoby A, Chadwick DW. The associations of psychopathology in epilepsy: a community study. Epilepsy Res 1996; 25: 29–39. Beran RG, Major M, Veldze L. Evaluation of the first 18 months of a specific rehabilitation programme for those with epilepsy. Clin Exp Neurol 1987; 23: 165–70. Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986; 1: 307–10. British Standards Institution. Precision of test methods I: guide for the determination and reproducibility of for a standard test method. BS 5497 Part 1. London: British Standards Institution, 1979. Cattell RB. The Scree Test for the number of factors. Multivar Behav Res 1966; 1: 245–76. Chaplin JE, Yepez E, Shorvon S, Floyd M. A quantitative approach to measuring the social effects of epilepsy. Neuroepidemiology 1990; 9: 151–8.
333
Dell J. Social dimensions of epilepsy: stigma and response. In: Whitman S, Hermann BP, editors. Psychopathology in epilepsy: social dimensions. New York: Oxford University Press, 1986: 185–210. Devinsky O, Vickrey BG, Cramer J, Perrine K, Hermann B, Meador K, et al. Development of the quality of life in epilepsy inventory. Epilepsia 1995; 36: 1089–104. Dodrill CB, Batzel LW, Queisser HR, Temkin NR. An objective method for the assessment of psychological and social problems among epileptics. Epilepsia 1980; 21: 123–35. Fleiss JL, Shrout PE. Approximate interval estimation for a certain intraclass correlation coefficient. Psychometrika 1978; 43: 259–62. Fraser RT, Clemmons D, Trejo W, Temkin NR. Program evaluation in epilepsy rehabilitation. Epilepsia 1983; 24: 734–46. Guldvog B. Patient satisfaction and epilepsy surgery. Epilepsia 1994; 35: 579–84. Guyatt GH, Berman LB, Townsend M, Pugsley SO, Chambers LW. A measure of quality of life for clinical trials in chronic lung disease. Thorax 1987; 42: 773–8. Hand DJ, Taylor CC. Multivariate analysis of variance and repeated measures: a practical approach for behavioural scientists. London: Chapman and Hall, 1987. Harwood RH, Rogers A, Dickinson E, Ebrahim S. Measuring handicap: the London handicap scale, a new outcome measure for chronic disease. Qual Health Care 1994; 3: 11–6. Hermann BP. Quality of life in epilepsy. J Epilepsy 1992; 5: 153–65. Hermann BP, Wyler AR. Depression, locus of control, and the effects of epilepsy surgery [published erratum appears in Epilepsia 1990; 31: 825]. Epilepsia 1989; 30: 332–8. Jacoby A. Epilepsy and the quality of everyday life. Findings from a study of people with well-controlled epilepsy. Soc Sci Med 1992; 34: 657–66. Jacoby A. Impact of epilepsy on employment status: findings from a UK study of people with well-controlled epilepsy. Epilepsy Res 1995; 21: 125–32. Jacoby A, Johnson A, Chadwick D. Psychosocial outcomes of antiepileptic drug discontinuation. Epilepsia 1992; 33: 1123–31. Jacoby A, Baker G, Smith D, Dewey M, Chadwick D. Measuring the impact of epilepsy: the development of a novel scale. Epilepsy Res 1993; 16: 83–8. Jacoby A, Baker GA, Steen N, Potts P, Chadwick DW. The clinical course of epilepsy and its psychosocial correlates: findings from a UK community study. Epilepsia 1996; 37: 148–61.
Collings JA. Epilepsy and well-being. Soc Sci Med 1990; 31: 165–70.
Jenkinson C, Coulter A, Wright L. Short Form 36 (SF 36) health survey questionnaire: normative data for adults of working age [see comments]. BMJ 1993; 306: 1437–40. Comment in: BMJ 1993; 306: 1429–30. Comment in: BMJ 1993; 307: 125–7.
Cronbach LJ. Coefficient alpha and the internal structure of tests. Psychometrika 1951; 16: 297–334.
Jenkinson C, Wright L, Coulter A. Criterion validity and reliability of the SF-36 in a population sample. Qual Life Res 1994; 3: 7–12.
de Haes JC, de Ruiter JH, Tempelaar R, Pennink BJ. The distinction between affect and cognition in the quality of life of cancer patients– sensitivity and stability. Qual Life Res 1992; 1: 315–22.
Johnson AL. Some statistical issues in quality of life measurements. In: Trimble MR, Dodson WE, editors. Epilepsy and quality of life. New York: Raven Press, 1994: 65–84.
334
O’Donoghue et al.
Kendrick AM, Trimble MR. Repertory grid in the assessment of quality of life in patients with epilepsy: the quality of life assessment schedule. In: Trimble MR, Dodson WE, editors. Epilepsy and quality of life. New York: Raven Press, 1994: 151–63.
new approach to the measurement of quality of life: the Patient Generated Index. Med Care 1996; 32: 1109–1126.
Liang MH, Larson MG, Cullen KE, Schwartz JA. Comparative measurement efficiency and sensitivity of five health status instruments for arthritis research. Arthritis Rheum 1985; 28: 542–7.
Smith D, Baker G, Davies G, Dewey M, Chadwick DW. Outcomes of add-on treatment with lamotrigine in partial epilepsy. Epilepsia 1993; 34: 312–22.
McDowell I, Newell C. Measuring health: a guide to rating scales and questionnaires. New York: Oxford University Press, 1987.
Streiner DL, Norman GR. Reliability. In: Steiner DL, Norman GR. Health measurement scales: a practical guide to their development and use. 2nd ed. Oxford: Oxford University Press, 1995: 104–27.
McHorney CA, Ware JE Jr, Raczek AE. The MOS 36-Item ShortForm Health Survey (SF-36): II. Psychometric and clinical tests of validity in measuring physical and mental health constructs. Med Care 1993; 31: 247–63. Mittan RJ. Fear of seizures. In: Whitman S, Hermann BP, editors. Psychopathology of epilepsy: social dimensions. New York: Oxford University Press, 1986: 90–121. Nelson E, Wasson J, Kirk J, Keller A, Clark D, Dietrich A, et al. Assessment of function in routine clinical practice: description of the COOP Chart method and preliminary findings. J Chronic Dis 1987; 40 Suppl 1: 55S–69S. Norusˇis MJ. Introductory and advanced statistics students guide. Chicago: SPSS, 1990. Nunnally JC, Bernstein IH. Psychometric theory. 3rd ed. New York: McGraw-Hill, 1993. O’Boyle CA, McGee H, Hickey A, O’Malley K, Joyce CR. Individual quality of life in patients undergoing hip replacement. Lancet 1992; 339: 1088–91. Patrick DL, Deyo RA. Generic and disease-specific measures in assessing health status and quality of life. [Review]. Med Care 1989; 27 (3 Suppl): S217–32. Peters DJ. Human experience in disablement: the imperative of the ICIDH. [Review]. Disabil Rehabil 1995; 17: 135–44. Ruta DA, Abdalla MI, Garratt AM, Coutts A, Russell IT. SF 36 health survey questionnaire: I. Reliability in two patient based studies. Qual Health Care 1994; 3: 180–5. Ruta DA, Garratt AM, Leng M, Russell IT, MacDonald LM. A
Selai CE, Trimble MR. Quality of life assessment in epilepsy: the state of the art. J Epilepsy 1995; 8: 332–7.
Taylor DC, Falconer MA. Clinical, socio-economic, and psychological changes after temporal lobectomy for epilepsy. Br J Psychiatry 1968; 114: 1247–61. Thompson PJ, Oxley J. Socioeconomic accompaniments of severe epilepsy. Epilepsia 1988; 29 Suppl 1: S9-S18. Trostle JA, Hauser WA, Sharbrough FW. Psychologic and social adjustment to epilepsy in Rochester, Minnesota. Neurology 1989; 39: 633–7. Vickrey BG, Hays RD, Graber J, Rausch R, Engel J Jr, Brook RH. A health-related quality of life instrument for patients evaluated for epilepsy surgery. Med Care 1992; 30: 299–319. Wade DT. Measurement in neurological rehabilitation. Oxford: Oxford University Press, 1992. Wagner AK, Keller SD, Kosinski M, Baker GA, Jacoby A, Hsu MA, et al. Advances in methods for assessing the impact of epilepsy and antiepileptic drug therapy on patients’ health-related quality of life. Qual Life Res 1995; 4: 115–34. Ware JE, Sherbourne CD. The MOS 36 item short form health survey (SF-36). I. Conceptual framework and item selection. Med Care 1992; 30: 473–83. World Health Organization. The international classification of impairments, disabilities, and handicaps. Geneva: World Health Organization, 1980. Zigmond AS, Snaith RP. The Hospital Anxiety and Depression Scale. Acta Psychiatr Scand 1983; 67: 361–70. Received January 9, 1997. Revised August 11, 1997. Accepted September 23, 1997
The subjective handicap of epilepsy
Questionnaire for Assessment of the Subjective Handicap of Epilepsy
Please read this first:
In this booklet most of the questions use the word ‘epilepsy’. * If you are still having seizures (‘fits’ or ‘turns’), the questions are about the effect of epilepsy on your life now. * If you have stopped having seizures (‘fits’ or ‘turns’) the questions are about whether the seizures you had in the past still have any effect on your life now (e.g. work, social life...). * To answer the questions simply place a tick in the box underneath the answer that comes closest to how you feel.
If you have any difficulties filling in the questionnaire, get someone to help you, but the answers should be all your own.
Now, the questions . . .
About your work Here are some questions about your main day time activity. This could be either paid work, studying, a training course, looking after the home, or perhaps something else.
There are separate questions depending on your main activity:
If you are in full-time or part-time paid employment : start the questionnaire on page 2
If you are in full-time education or training :
start the questionnaire on page 3
Everyone else :
start the questionnaire on page 4
335
336
O’Donoghue et al. otherwise go on to the next page ⇒
IF YOU DO PAID WORK... Please answer the questions on this page
1a. In the last 6 months has epilepsy caused you problems doing your job ?
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Totally
A lot
Partly
A little
Not at all
[ ]
[ ]
[ ]
[ ]
[ ]
Very Happy
Happy
It is OK
Unhappy
Very Unhappy
[ ]
[ ]
[ ]
[ ]
[ ]
2a. In the last 6 months have you had time off work because of epilepsy ?
3a. In the last 6 months have you worried about losing your job because of epilepsy ?
4a. How often do you feel tired and drowsy during the day ?
5a. How often do you have problems with your memory ?
6a. Does epilepsy prevent you doing the type of job you would really like to do ?
7a. How happy are you overall in your job ?
please go to question 8 on page 5
The subjective handicap of epilepsy
337
otherwise go on to the next page ⇒
IF YOU ARE STUDYING OR ARE ON A COURSE... Please answer the questions on this page
1b. In the last 6 months has epilepsy caused you problems doing your work ?
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Totally
A lot
Partly
A little
Not at all
[ ]
[ ]
[ ]
[ ]
[ ]
Very Happy
Happy
It is OK
Unhappy
Very Unhappy
[ ]
[ ]
[ ]
[ ]
[ ]
2b. In the last 6 months have you had time off because of epilepsy ?
3b. In the last 6 months have you been worried that you might have to stop your course because of epilepsy ?
4b. How often do you feel tired and drowsy during the day ?
5b. How often do you have problems with your memory ?
6b. Does epilepsy prevent you doing the type of course or training you would really like to do ?
7b. How happy are you overall doing your course ?
please go to question 8 on page 5
338
O’Donoghue et al.
EVERYONE ELSE... Please answer the questions on this page
do not answer these questions if you filled in page 2 or 3
1c. In the last 6 months has epilepsy caused you problems doing your usual ‘day-to-day’ activities ?
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
I need help with everything [ ]
I need a lot I need some of help help
I need a little help
I need no help
[ ]
[ ]
[ ]
[ ]
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Totally
A lot
Partly
A little
Not at all
[ ]
[ ]
[ ]
[ ]
[ ]
Very Happy
Happy
It is OK
Unhappy
Very Unhappy
[ ]
[ ]
[ ]
[ ]
[ ]
2c. In the last 6 months have you had to take some time off from your usual ‘day-to-day’ activities because of epilepsy ?
3c. Do you need help looking after your home because of your epilepsy ?
4c. How often do you feel tired and drowsy during the day ?
5c. How often do you have problems with your memory ?
6c. Does epilepsy prevent you doing the type of job you would really like to do ?
7c. How happy are you overall with the way you spend your average day ?
please go to question 8 on the next page
The subjective handicap of epilepsy
339
Your personal life Here are some questions about your relationships with other people. Some questions are quite personal, but we would find it helpful to know how epilepsy is affecting you in these matters.
8. Does your epilepsy create problems in getting on with close relations (e.g. children, parents...) ?
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Very Happy
Happy
It is OK
Unhappy
Very Unhappy
[ ]
[ ]
[ ]
[ ]
[ ]
Does not apply to me [ ]
9. Does your epilepsy cause problems in your relationship with friends ?
10. Does your epilepsy cause problems making new friends ?
11. Does your epilepsy make you feel lonely ?
12. How happy are you overall with your social life outside the family ?
place ticks with care !
340
O’Donoghue et al.
13. How happy are you overall with your home life ?
Very Happy
Happy
It is OK
Unhappy
Very Unhappy
[ ]
[ ]
[ ]
[ ]
[ ]
Here are some questions about how epilepsy affects what you do for leisure and fun.
14. In the last 6 months has epilepsy prevented you from doing leisure activities ?
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Totally
A lot
Partly
A little
Not at all
[ ]
[ ]
[ ]
[ ]
[ ]
Very Happy
Happy
It is OK
Unhappy
Very Unhappy
[ ]
[ ]
[ ]
[ ]
[ ]
15. How much does epilepsy prevent you from doing the type of leisure activity you would like to do ?
16. How happy are you overall with the way you can spend your leisure time ?
please carry on with question 17 on the next page
The subjective handicap of epilepsy Thinking about the last 6 months... 17. Has epilepsy made you feel physically unwell ?
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Very often
Often
Sometimes
Rarely
Never
[ ]
[ ]
[ ]
[ ]
[ ]
Totally
A lot
Quite a bit
A little
Not at all
[ ]
[ ]
[ ]
[ ]
[ ]
18. Has epilepsy caused you injury or pain ?
19. Does epilepsy cause you annoying problems in ‘day-to-day’ life ?
20. Does epilepsy cause you problems travelling and getting about ?
21. Does your epilepsy make you feel that you are not in full control of your life ?
22. Does your epilepsy make you feel you cannot do things as well as most people ?
23. Do you worry about having another seizure ?
24. Do you worry about being in public because of your epilepsy ?
25. Overall how much does epilepsy affect your life ?
341
342
O’Donoghue et al.
Your life compared to 1 year ago We would like to know if there has been any change overall in your life compared to 1 year ago.
26. Overall how has your life been compared to 1 year ago ?
Much better
Better
The same
Worse
Much worse
[ ]
[ ]
[ ]
[ ]
[ ]
Much better
Better
The same
Worse
Much worse
[ ]
[ ]
[ ]
[ ]
[ ]
Much better
Better
The same
Worse
Much worse
[ ]
[ ]
[ ]
[ ]
[ ]
Much better
Better
The same
Worse
Much worse
[ ]
[ ]
[ ]
[ ]
[ ]
Much better
Better
The same
Worse
Much worse
[ ]
[ ]
[ ]
[ ]
[ ]
Much better
Better
The same
Worse
Much worse
[ ]
[ ]
[ ]
[ ]
[ ]
Much more
A bit more The same
A bit less
Much less
[ ]
[ ]
[ ]
[ ]
27. Compared to 1 year ago how have your close relationships been ?
28. Compared to 1 year ago how has work been for you ?
29. Compared to 1 year ago how has the control of your epilepsy been?
30. Compared to 1 year ago how has your social life been ?
31. Compared to 1 year ago how has your leisure time been ?
and . . .
32. Compared to 1 year ago how much do you enjoy life ?
[ ]
The subjective handicap of epilepsy
Scoring instructions
Questions 1, 2, 3, 4, 5, 8, 9, 10, 11, 14, 17, 18, 19, 20, 21, 22, 23 and 24: very often 5 1; often 5 2; sometimes 5 3; rarely 5 4; never 5 5. Questions 6 and 15: totally 5 1; a lot 5 2; partly 5 3; a little 5 2; not at all 51. Question 25: totally 5 1; a lot 5 2; quite a bit 5 3; a little 5 4; not at all 5 5. Questions 7, 12, 13 and 16: very happy 5 5; happy 5 4; it is OK 5 3; unhappy 5 2; very unhappy 5 1. Questions 26–31: much better 5 5; better 5 4; the same 5 3; worse 5 2; much worse 5 1. Question 32: much more 5 5; a bit more 5 4; the same 5 3; a bit less 5 2; much less 5 1.
Total scores
Work and activity 5 ((((1 1 2 1 3 1 6 1 14 1 15 1 19 1 20) – 8)/32) 3 100) Social and personal 5 ((((8 1 9 1 10 1 11) – 4)/16) 3 100) Physical 5 ((((4 1 5 1 17 1 18) – 4)/16) 3 100) Self-perception 5 ((((21 1 22 1 23 1 24 1 25) – 5)/20) 3 100) Life-satisfaction 5 ((((7 1 12 1 13 1 16) – 4)/16) 3 100) Change 5 ((((26 1 27 1 28 1 29 1 30 1 31 1 32) – 7)/28) 3 100) Copies of this questionnaire are available on request from the corresponding author Dr M. F. O’Donoghue
343
