word ®nding problems, tangentiality, distractability, disinhibition and di¬culty with initiation. Finally, two questions measuring rate completed the 30 item pool.
aphasiology, 2000, vol. 14, no. 3, 251±268
Measuring perception of communicative ability : the development and evaluation of the La Trobe communication questionnaire J ACI N T A M. DO UGL A S, C HR I S TI NE A. O ’F LAHE R T Y and PAME L A C. S NOW School of Human Communication Sciences, La Trobe University, Melbourne, Australia (Received 7 July 1999; accepted 18 May 1999)
Abstract The La Trobe communication questionnaire (LCQ) was designed to measure perceived communicative ability. It was developed to enable collection of information from various sources including the self-perceptions of individuals as well as the perceptions of close others. In this paper we report the development of the questionnaire, its psychometric properties and normative data for the perceptions of young adults and the comparative perceptions of their close others. Participants in the study were 256 adults comprising 147 primary subjects and 109 close others. Primary subjects ranged in age from 16±39 years with a mean age of 20.6 years. The 30 item questionnaire was structured using a modi®ed Likert-type scale with four possible levels of response: (1) never or rarely ; (2) sometimes ; (3) often ; and (4) usually or always. Internal consistency was high (Cronbach’s alpha 5 0.8596) and good stability over time for self-report was demonstrated (r 5 0.7558). There was a signi®cant diåerence ( p ! 0.0001) between the perceptions of primary subjects and close others with primary subjects perceiving themselves to have more frequent communication di¬culties, than did their close others. Overall, our ®ndings suggest that the LCQ is a promising means of measuring perceived communicative ability in young adults.
Introduction Altered communication skills are a frequent and well-established consequence of acquired brain damage and progressiveneurological disorder. In clinical practice, there are many measures available to assess language and speech processes and to a lesser extent pragmatics. However, there are substantially fewer tools that have been designed to measure communicative ability as perceived by individuals with impaired communication skills themselves or those close to them. Further, there is a notable lack of tools that allow comparison with normative data. In an attempt to ®ll this gap, the La Trobe communication questionnaire (LCQ) has been developed and initially evaluated on a sample of young adults from the general Address correspondence to : Dr Jacinta M. Douglas, e-mail : j.douglas! ’ 2000 Psychology Press Ltd http:} } www.tandf.co.uk} journals} pp} 02687038.html
latrobe.edu.au
252
J. M. Douglas et al.
population. The LCQ was speci®cally designed to measure perceived communicative ability and as such is appropriate for collecting information from various sources including the self-perceptions of individuals as well as the perceptions of others with whom they converse and interact (e.g. relatives and friends or rehabilitation workers in clinical cases). The LCQ was originally developed to assess communicative ability as perceived by young adults who had sustained traumatic brain injury (TBI) and their relatives. There are several rating scales and questionnaires available that evaluate the cognitive and behavioural consequences from the perspective of individuals with TBI and their relatives, including those developed by Kreutzer et al. 1996, McKinlay et al. 1981 and Prigatano et al. 1990. Some of these scales have addressed communication by including a small number of items (e.g. Prigatano’s Patient Competency Rating Scale) or a short subscale (e.g. Kreutzer’s Neurobehavioural Functioning Inventory) dedicated to communication di¬culties within the measure. However, a single measure devoted to measuring communicative ability as seen by injured individuals and their relatives was not available. Nor was a measure available that allowed for the comparison of perceptions in clinical populations with the perceptions of healthy adults. Relatives’ reportsof a patient’s communicative competency can be important for several reasons. First, their information may be the only source of comparison available at the time of diagnosis.Second, relatives have knowledge of the patient’s premorbid functioning and often spend considerably more time with the patient in diåerent situations than busy professionals.Consequently,they may be better able to evaluate ability more reliably than clinicians. Finally, relatives’ views of patients’ abilities are important when planning rehabilitation goals and therapy (Prigatano and Altman 1990). Despite the advantages of using relatives’ perceptions of the problems experienced by family members with TBI, there are several factors which may shape relatives’ perceptions and compromise objective accuracy. Such factors range from the subjective burden and anxiety perceived by relatives (McKinlay et al. 1981; McKinlay & Brooks,1984) to the psychological coping mechanisms used by relatives and their own personality characteristics (DePompeii and Zarski 1989, Romano1974, Tanner and Gerstenberger1988). As well as considering factors that may shape relatives’ perceptions in clinical cases, it would be useful to consider their perceptions in the context of some knowledge of how relatives perceive the communicative ability of their family members in the normal population. Thus, collection of normative data may well assist interpretation of close other ratings in clinical settings. Self-reports by the patient can also be informative in assessing disability following brain damage (Allen and Ruå 1990, Diller and Gordon 1981, Elsass and Kinsella 1987). However, interpretation of responses from self-administered procedures must be carried out with caution. This is particularly the case when awareness of de®cits is itself compromised as a result of TBI. Although signi®cant underestimation of problems on self-report following TBI has been reported by several researchers (Cavallo et al. 1992, Ehrlich and Barry 1989, Fordyce and Roueche 1986, Prigatano 1991), a clear picture of underestimation or minimization of disability does not always emerge (Goldstein and McCue 1995). Chelune et al. (1986) reported ®nding not only individuals who denied their problems but also those who exaggerated their de®cits. Further, there is evidence to suggest that greater awareness of de®cits may well develop with increasing time post-injury
La Trobe communication questionnaire
253
(Godfrey et al. 1993). Nevertheless, regardless of level of insight or awareness, it is important to recognize that self-report data provides ®rst hand information about the changes perceived from the injured individual’s own perspective (Tyerman and Humphrey 1984). Knowledge of that perspective is an essential component of eåective intervention. To achieve greater objectivity, clinician-investigatorshave been asked to rate the performance of their patients with TBI. Although an absolute trend has not emerged, there is some evidence to suggestthat clinicians’ ratings of their patients’ performance are more negative than those of the patients and} or their relatives (Fordyce and Roueche 1986, McNeill- Brown and Douglas 1997, Prigatano and Fordyce 1986). Clinicians have little knowledge of their patients’ premorbid status and thus should have no motivation to give anything other than an accurate account of what they perceive. However, by not accounting for a patient’s premorbid ability or sociocultural background, the therapist may well rate the patient’s performance harshly by comparing it to an ill-de®ned ideal of `normal’ behaviour (Snow et al. 1995). The availability of normative data within the construct of communicative ability would in part alleviate this problem in the clinical setting. Further, knowledge of what is normal or customarily expected is essential for illustrating the extent of de®cit to patients themselves, their relatives, the therapists working with them, and those who approve funding for rehabilitation. For this reason, the LCQ was initially developed and psychometrically evaluated on a group of normal healthy young adults who were selected broadly to re¯ect the demographics of the TBI population.It has since been used with a small group of adults with severe TBI, their relatives, and rehabilitation workers within the ®rst year postinjury (McNeil-Brown and Douglas 1997) and a larger group of severely injured adults and their close others more than 2.5 years post-injury(Snow et al. 1999). In this paper we report: (1) the development of the questionnaire; (2) its content and temporal reliability ; (3) the eåect of age, social desirability, and gender on the measure; and (4) preliminary evaluation of its validity. Normative data are presented for the perceptions of young adults within the age range of 16±40 years. The comparative perceptions of the close others of these young adults are also reported. Method Participants Four hundred and forty six adults, comprising 250 primary subjects (Ss) and 196 close others (Os), were recruited for the study. The age range for primary subjects was restricted to 16±40 years in order to re¯ect the age range associated with the peak incidence of TBI in the general population. For the original 250 primary subjects, age ranged from 16±39 years with a mean of 20.3 years. They were evenly represented in terms of gender, 120 males and 130 females. These volunteers were recruited from an eastern metropolitan multi-campus Technical and Advanced Further Education (TAFE) college, a northern metropolitan multi-campus university, and a north-western metropolitan high school in Melbourne, Victoria, Australia. TAFE volunteers were recruited from the departments of cabinet making, plumbing, motor mechanics, catering and marketing. University students were from undergraduate professional vocation courses in nursing and speech
J. M. Douglas et al.
254
pathology. Students, who were accepted into the speech pathology course, participated in the study during orientation week before they had attended any classes. High school participants were in their ®nal year of high school completing the Victorian Certi®cate of Education (VCE). Each primary subject selected a `close other’, de®ned as a person who knew the participant well, preferably resided with them and who had known them for more than ®ve years. Of the 196 close others who returned completed questionnaires, 139 were in the immediate or extended family of the respective primary subject and 57 were friends (categories included `girlfriend’, `boyfriend’, and `best friend’). The age range of these respondentswas 15±61 years with a mean age of 32.7 years. The data from all recruited participants (Ss and Os) was screened and participants were excluded from the study on the following grounds: E
E
E E
E
Ss had suåered a head injury producing loss of consciousness or concussion (n 5 54). This number represents 22% of the volunteers originally recruited for the study; Ss reported a history of psychiatric illness (n 5 3 ; all of these subjects had also reported head injury); Os whose relative (Ss) was in the above groups; participants (Ss and Os) were assessed as having completed the communication questionnaire with a response bias (Ss n 5 67; Os n 5 9. Some of these Ss had also reported head injury). Respondents were deemed to show a response bias when they responded in the same direction to all LCQ items, including those worded in reverse direction (see section headed Development of the LCQ); and participants (Ss and Os) had failed to complete all the items in the data collection package.
The remaining sample comprised 147 primary subjects and 109 close others. These participants constituted the sample for the study. The primary subject group was now 88 females (age range 16±39 years, mean age 21.2 years) and 59 males (age range 16±36 years, mean age 19.9 years). Demographic data for this sample are presented in Table 1. Father’s occupation was used as an indicator of socioeconomic status for the participants. Fifty eight percent of the female participants and 71% of the males reported father’s occupation as non-professional, trade or unskilled. The mean age of the close others who remained in the study was 32.76 years. Materials and procedure A survey package was developed and distributed to volunteers at the educational institutions they attended. Completed protocols were collected 1±2 weeks later. Test-retest data over an 8 week period was collected on a subgroup of 48 participants, 24 primary subjects and their respective close others. The survey package consisted of a shortexplanation of the aims of the project, a consent form, a general demographic questionnaire, the LCQ, self-report (LCQ-S) and close other} relative (LCQ-O) versions, and a modi®ed Marlowe-Crowne Social Desirability Scale (Strahan and Gerbasi 1972).
La Trobe communication questionnaire
255
Table 1. Demographic data : primary Subjects (n 5 Females (n 5
Variable Completed year 11 or below Completed year 12 Part-completed certi®cate or diploma Completed certi®cate or diploma Part-completed degree Completed degree Occupation Professional White collar non-professional Skilled trade Unskilled Student Current employment status Full time Part-time or casual Unemployed seeking employment Unemployed not seeking employment Father’s occupation Professional White collar non-professional Skilled trade Unskilled Unemployed} retired Deceased} not disclosed
88)
147) Males (n 5
59)
Absolute frequency
Relative frequency (%)
Absolute frequency
Relative frequency (%)
8 1 13 1 56 9
9 1.1 14.8 1.1 63.6 10.2
10 Ð 41 2 3 3
16.9
0 5 3 0 80
0 5.7 3.4 0 91
2 0 35 1 21
3.4 0 59.3 1.7 35.6
9 49 11 19
10.2 56.7 12.5 21.6
38 9 6 6
64.4 15.2 10.2 10.2
22 26 23 2 5 10
25.0 29.0 26.1 2.8 5.7 11.4
11 18 20 4 3 3
18.6 30.5 33.9 6.8 5.1 5.1
69.5 3.4 5.1 5.1
Development of the La Trobe communication questionnaire (LCQ) Item selection Two considerations guided selection of item content for the LCQ: (1) the fundamental characteristics of eåective normal communication; and (2) the nature of cognitive-communicative breakdown following diåuse damage to the brain. The Grician Co-operative Principle of normal discourse(Grice 1975) as operationalized by Damico’s Clinical Discourse Analysis (CDA) (Damico 1985) was used to identify the eåective normalcommunication behavioursmeasured within the LCQ. In addition, the literature describing the cognitive-communication de®cits associated with TBI (e.g. Coehlo et al. 1991, Hagen 1984, Hartley and Jensen 1992, Hartley and Levin 1990) was used to augment item content to ensure adequate sampling of the domain of cognitive-communicative abilities. The Grician Co-operative Principle describes the conditions governing normal discourse, irrespective of context and subject matter. There is a universal expectation that interactants will `make (their) conversational contribution such as is required, at the stage at which it occurs, by the accepted purposeor direction of the talk exchange in which (they) are engaged’ (Grice 1975). Grice de®ned four conversational maxims in his Co-operative Principle. The quantity maxim relates to the amount of information provided in an interaction : make your contribution
256
J. M. Douglas et al.
as informative as is required and not more informative than is required for the purposeof the current exchange. The quality maxim relates to the accuracy of the contribution: do not say what you believe to be false and do not say that for which you lack adequate evidence. The relation maxim involves the relevance of the contribution: say what is relevant to the current exchange. Finally, the manner maxim relates not to what is said but how it is said : avoid obscurity and ambiguity of expression and be brief and orderly. Grice’s Co-operativePrinciple formed the framework for Damico’s CDA (1985). CDA consists of 17 parameters which measure problem behaviours across Grice’s four maxims. Twenty of the 30 items of the LCQ were constructed to evaluate the problem behavioursoutlined in CDA. Cognitive-communicativeconstructswhich are particularly vulnerable to fronto-temporal and diåuse brain damage provided the basis for 8 of the remaining 10 items. These constructsincluded memory de®cit, word ®nding problems, tangentiality, distractability, disinhibition and di¬culty with initiation. Finally, two questions measuring rate completed the 30 item pool. The full set of the theoretical constructs sampled and the questions generated to measure di¬culty within them are shown in Table 2. Structure of the LCQ The LCQ consists of two forms: form S to be administered to the primary subject and form O to the subject’s nominated close other. The forms are identical in content with the exception that form O uses the third person when describing the communication behaviours. A variation of form O is also available for use with rehabilitation workers when data is collected on clinical populations. The 30 item questionnairewas structuredusing a modi®ed Likert-type scale with four possible levels of response for each question: (1) never or rarely; (2) sometimes; (3) often; and (4) usually or always. All the questions were framed so that responses were expressed in terms of frequency of occurrence rather than qualitative judgements about level of di¬culty. A frequency of occurrence measure was used for two principal reasons. First, a behavioural frequency judgement allows data to be collected across a variety of informants as well as the identi®ed individual. All that is required of informants is that they have had the opportunity to observe the identi®ed individual in communicative interactions. Second, individuals with brain injury appear to ®nd frequency ratings easier to make than level of di¬culty or severity rating (Douglas 1994). This is not surprising. Frequency ratings require a more concrete accounting of a situation, while di¬culty ratings require a subjective sense of what is normal and not normal and an ability to evaluate oneself against that understanding.According to Prigatano (1991), this subjective sense of normality may well be altered as a result of brain damage. Consequently, this altered sense of normality could readily form the basis for impaired awareness of de®cit following brain injury. Wording in 24 of the 30 items was such that increased frequency of occurrence represented increased perceived di¬culty. For example : Item 1, `When talking to others do you leave out important details ? ’ Response scoring: never or rarely-1; sometimes-2; often-3; and usually or always-4. The remaining 6 items (items 11, 15, 19, 21, 23 and 28) require reverse scoring. In these items the lowest frequency rating represents the highest perceived di¬culty. For example : Item 19, `When talking to others do you keep track of the main details of conversations? ’ Response
La Trobe communication questionnaire
257
Table 2. Theoretical constructs and communication scale items Constructs and parameters
LCQ items When talking to others do you :
Quantity Insu¬cient information Non-speci®c vocabulary Information redundancy Need for repetition Quality Message inaccuracy
Relation Poor topic maintenance Inappropriate response Situational inappropriateness Inappropriate speech style Manner Linguistic non-¯uency Revision behaviour Failure to structure discourse Delay before responding Turn-taking di¬culty Gaze ine¬ciency Inappropriate intonational contour Cognitive Constructs Memory de®cit Word ®nding di¬culty Tangentiality Distractability Disinhibition } Impulsivity Di¬culty with initiation Rate
Ques. 1. Leave out important details ? Ques. 2. Use a lot of vague or empty words such as `you know what I mean ’ instead of the right word? Ques. 3. Go over and over the same ground in conversation? Ques. 25. Carry on talking about things for too long in your conversations? Ques. 14. Need the other person to repeat what they have said before being able to answer ? Ques. 15. Give people information that is not correct ? Ques. 24. Allow people to assume wrong impressions from your conversations? Ques. 28. Give information that is completely accurate ? Ques. 4. Switch to a diåerent topic of conversation too quickly ? Ques. 26. Have di¬culty thinking of things to say to keep the conversation going? Ques. 20. Give answers that are not connected to the question? Ques. 9. Say or do things others might consider rude or embarrassing ? Ques. 21. Find it easy to change your speech style (e.g. tone of voice, choice of words) according to the situation you are in ? Ques. 10. Hesitate, pause or repeat yourself? Ques. 16. Make a few false starts before getting your message across ? Ques. 23. Put ideas together in a logical way ? Ques. 5. Need a long time to think before answering the other person? Ques. 11. Know when to talk and when to listen ? Ques. 6. Find it hard to look at the other speaker ? Ques. 17. Have trouble using your tone of voice to get the message across ? Ques. 19. Keep track of the main details of conversations? Ques. 14. Need the other person to repeat what they have said before being able to answer ? Ques. 7. Have di¬culty thinking of the particular word you want ? Ques. 12. Get `side-tracked ’ by irrelevant parts of the conversation? Ques. 13. Find it di¬cult to follow group conversations? Ques. 29. Lose track of conversations in noisy places ? Ques. 27. Answer without taking time to think about what the other person has said ? Ques. 22. Speak too quickly ? Ques. 18. Have di¬culty getting the conversation started? Ques. 30. Have di¬culty bringing the conversation to a close ? Ques. 8. Speak too slowly Ques. 22. Speak too quickly
scoring: never or rarely-4; sometimes-3; often-2; and usually or always-1. These six items were distributed randomly throughout the questionnaire as internal response bias checks. They were included to enable identi®cation of respondents with a tendency to agree (or disagree) with questions regardless of their content (Selltiz et al. 1976). There continues to be some controversyover the magnitude of
J. M. Douglas et al.
258
the contribution of response sets to the variance of self-report inventories, with some authors claiming strong evidence that their contribution to variance is negligible (Anastasi 1982). For the purposesof the LCQ’s normal data collection, a responseset checking procedurewas included to enable elimination of data from respondentsevidencing a response set bias. Further, given that the questionnaire is ultimately intended for use with a brain damaged population and given that individuals within this population may have a tendency to perseverate, there will be greater need than usual to monitor for response set. A second responseformat has been included in the questionnairestructureto use with clinical populations. This response format can be used to elicit a premorbid versus postmorbid change judgement or a change judgement over a speci®ed period of time. After completing the frequency of occurrence rating for each item, the respondentis required to make a judgement about whether the behaviour has increased, decreased or remained the same since the injury or over a speci®ed period of time (e.g. past 3 months, since discharge). This responseformat has been used in earlier versions of the LCQ used with patients with TBI and their relatives (Gillies and Douglas 1990, Snow et al. 1995). Pilot study The LCQ was pretested to ascertain if question content could be understoodand interpreted as intended. Volunteer participants in the pilot study were 77 ®rst year university students and 35 close others. The questionnaires were administered to the primary subjects in the presence of one of the authors and respondents were asked for their interpretations of the items. Items that were unclear or caused di¬culties were identi®ed. Close other questionnaires were returned within a week with written feedback about item content and clarity. Nine questions were modi®ed as a result of subject feedback and to better accommodate the requirement for internal response set assessment. Social desirability scale The tendency to respond systematically in a way that re¯ects what is perceived as socially desirable or expected threatens the reliability and validity of questionnaires and scales (Anastasi 1982). Consequently, it is important to measure the degree to which results re¯ect the construct being studied or the general construct of social desirability. In the present study,a modi®ed version of the Marlowe-CrowneSocial Desirability Scale (M-C SDS) (Strahan and Gerbasi 1972) was included to assess the in¯uence of social desirability on performance on the LCQ. Strahan and Gerbasi’s shorter version of the social desirability scale correlates well with the original version developed by Crowne and Marlowe in 1960. Results Reliability, temporal stability , and the eåect of age and social desirability on the LCQ Corrected item-to-scale correlations for both the primary subject group (Ss) and close other group (Os) are reported in Table 3. The correlations indicate that the developmentof the scale was successfulin achieving reasonably good homogeneity
La Trobe communication questionnaire
259
Table 3. Corrected item-to-scale correlations for LCQ: primary subjects (n 5 147) close others (n 5 109)
Questionnaire items 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
Corrected item-scale correlation primary subjects (n 5 147)
Corrected item-scale correlation close others (n 5 109)
0.3303 0.3591 0.4162 0.3335 0.2973 0.2354 0.4666 0.3251 0.2495 0.4951 0.3665 0.4341 0.3949 0.4404 0.3359 0.4157 0.4661 0.3357 0.6134 0.3068 0.3461 0.1995 0.5226 0.4497 0.2398 0.3758 0.4046 0.4584 0.3344 0.2797
0.4676 0.4764 0.5201 0.4159 0.3537 0.2113 0.5642 0.4147 0.4093 0.5721 0.3538 0.5994 0.3261 0.4484 0.3370 0.3789 0.2139 0.2881 0.1661 0.5816 0.3209 0.3384 0.4760 0.2663 0.3372 0.3437 0.4602 0.4669 0.4084 0.3973
Table 4. Reliability and temporal stability of the LCQ
Reliability coe¬cients
Primary subjects (n 5 147) 30 Items
Close others (n 5 109) 30 Items
Alpha Standardized alpha Guttman’s split-half Alpha part 1 Alpha part 2 Test-retest (8 weeks)
0.8538 0.8596 0.7791 0.7568 0.7710 0.7558 (n 5 24)
0.8551 0.8719 0.8278 0.8059 0.7210 0.4784 (n 5 24)
of item content. Internal consistency of the scale was estimated using Cronbach’s alpha and Guttman’s Split half technique (Table 4). Internal consistency measures were all high. Test-retest coe¬cients across an 8 week interval were estimated using Pearson’s r and are shown in Table 4. The scale has acceptable stability over
J. M. Douglas et al.
260
Table 5. Descriptive data (mean, standard deviation, and range) for the LCQ for primary subjects (n 5 147) and close others (n 5 109) Primary subjects
Close others
LCQ item
Mean
SD
Range
Mean
SD
Range
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Mean item Mean total
1.65 2.04 1.68 1.80 1.54 1.36 2.04 1.18 1.65 1.86 1.76 2.09 1.43 1.55 1.43 1.60 1.47 1.76 1.90 1.48 1.94 2.15 1.97 1.63 1.78 2.03 1.90 2.06 2.20 1.63 1.75 52.47
0.58 0.63 0.74 0.74 0.68 0.62 0.83 0.47 0.75 0.65 0.88 0.76 0.68 0.67 0.60 0.68 0.75 0.79 0.92 0.63 1.05 0.91 0.78 0.69 0.65 0.75 0.74 0.79 0.72 0.71 0.26 9.62
1±4 1±4 1±4 1±4 1±4 1±3 1±4 1±3 1±4 1±3 1±4 1±4 1±4 1±4 1±4 1±4 1±4 1±4 1±4 1±4 1±4 1±4 1±4 1±4 1±4 1±4 1±4 1±4 1±4 1±4 1.18±2.19 31±78
1.60 1.99 1.47 1.61 1.37 1.25 1.63 1.12 1.64 1.50 1.97 1.68 1.27 1.48 1.36 1.34 1.30 1.48 1.89 1.35 1.96 1.73 1.61 1.54 1.68 1.61 1.69 1.83 1.72 1.53 1.57 47.17
0.60 0.79 0.69 0.75 0.63 0.51 0.65 0.45 0.76 0.66 1.04 0.67 0.50 0.63 0.54 0.49 0.50 0.63 1.10 0.66 0.99 0.86 0.75 0.65 0.84 0.71 0.73 0.85 0.70 0.74 0.22 9.93
1±3 1±4 1±3 1±4 1±4 1±3 1±3 1±4 1±4 1±4 1±4 1±4 1±3 1±4 1±3 1±3 1±3 1±4 1±4 1±4 1±4 1±4 1±4 1±4 1±4 1±4 1±4 1±4 1±4 1±4 1.12±1.99 30±77
time for self-reportof the constructwith a poor correlation foundin the close other test-retest data. The discriminant validity of the scale was estimated by correlating Ss scores on the LCQ with two variables : social desirability and age. We did not expect a signi®cant correlation with age, because the age range had been restricted to represent this demographicfeature of the TBI population. Using Pearson’s r, both age (r 5 2 0.001) and social desirability (r 5 2 0.2431) were found to be poorly correlated with LCQ scores. Less than one per cent of shared variance could be accounted for by the relationship of LCQ scores with either age (0%) or social desirability (0.06 %).
La Trobe communication questionnaire
261
Self-perception and close other perception of communicative ability in normal young adults Descriptive statistics for each item of the scale for self and close other respondents are presented in Table 5. For the primary subjects, none of the items of the LCQ produced a mean score above 2.2. For the close others none of the items produced a mean score of more than 2.0. The descriptive data for the sample means for individual item scores and total scores on the LCQ are also shown in Table 5. Total scores on the LCQ for self and close other reports were normally distributed. For primary subjects the kurtosis and skewness of the distribution were 2 0.5842 and 0.2459 respectively. For close others, the distributionwas less kurtosed(0.006) and slightly more positively skewed (0.6436). A two-tailed t-test for paired samples was used to assess whether there was a signi®cant diåerence between primary subjects’ self-perception of communicative ability and that of their close others. Data from pairs for whom self and close other scores were available (n 5 109) were used in this analysis. Overall, close others perceived the communicative abilities of the primary subjects to be signi®cantly better than did the primary subjects themselves (t 5 6.20, p ! 0.0001). Using an alpha level of 0.0017 (Bonferroniadjusted for multiple} 30 item comparisons)and two-tailed t-tests for paired samples, signi®cant diåerences in perceived frequency of di¬culty were found on 10 of the 30 items. On all of these 10 items, primary subjects perceived signi®cantly more frequent di¬culties than did their close others. Those items which elicited signi®cantly diåerent perceptions included: (3) Go over and over the same ground in conversation (t 5 3.57, p ! 0.0017); (7) Have di¬culty thinkingof a particular word (t 5 6.20, p ! 0.00001); (10) Hesitate, pause, and} or repeat yourself (t 5 5.50, p ! 0.00001); (12) Get side-tracked by irrelevant parts of conversations (t 5 5.10, p ! 0.00001); (16) Make a few false starts before getting the message across (t 5 3.70, p ! 0.0017); (18) Have di¬culty getting conversations started (t 5 3.80, p ! 0.0017); (22) Speak too quickly (t 5 6.84, p ! 0.00001); (23) Put ideas together in a logical way (t 5 3.56, p ! 0.0017); (26) Have di¬culty thinkingof things to say to keep conversationsgoing (t 5 4.78, p ! 0.00001); and (29) Lose track of conversations in noisy places (t 5 5.40, p ! 0.00001). The role of gender in self-perception of communicative ability Following `clean up’ of the original raw data, the primary subject sample was biased in favour of female participants who had reached university level education. The sample (n 5 147) consisted of 88 females, 64 of whom were enrolled in undergraduateuniversitycourses.Of the 59 male participants, only six had attained university level education. There was also an age diåerence between male and female subjects (females’ mean age 21.2 years ; males’ mean age 19.9 years). A two tailed t-test assuming unequal variance revealed the age diåerence was not signi®cant (t 5 1.73, p 5 0.086). Table 6 summarizes the descriptive data for the sample means for individual item scores and total scores on the LCQ for males and females. The total scores for females and males were normally distributed. For females the kurtosis and skewness of the distribution were 2 0.3387 and 0.3968 respectively. For males, the distributionwas more kurtosed(2 0.6071) and slightly negatively rather than positively skewed (2 0.0135).
J. M. Douglas et al.
262 Table 6.
Descriptive data for item mean and total scores on the LCQ for females (n 5 males (n 5 59) Females
Mean Standard deviation Minimum Maximum Range
88) and
Males
Item mean
Total mean
Item mean
Total mean
1.68 0.30 1.03 2.40 1.36
50.47 9.07 31 72 41
1.84 0.32 1.13 2.60 1.47
55.44 9.74 34 78 44
A two-tailed t-test assuming unequal variance was used to assess whether there was a signi®cant diåerence between females’ self-perception of communicative ability and that of males. Overall, males perceived themselves to have signi®cantly more frequent di¬culties than did females (t 5 3.11, p ! 0.01). Using an alpha level of 0.0017 (Bonferroni adjusted for multiple} 30 item comparisons) and twotailed t-tests assuming unequal variance, signi®cant diåerences in perceived frequency of di¬culty were found on 2 of the 30 individual items. On both items, males perceived signi®cantly more frequent di¬culties than did females. The two items which elicited signi®cantly diåerent perceptions were : (19) Keep track of the main details of conversations (t 5 4.80, p ! 0.0017); and (21) Changing speech style according to the situation (t 5 3.37, p ! 0.0017). Due to the education level diåerence between females and males, the eåect of gender was further evaluated while controlling for education. A hierarchical regression was employed to determine if addition of information regarding gender signi®cantly improved the prediction of communicative ability beyond that aåorded by age and education. Education was coded in a dichotomousfashion with two broad categories : (1) university level education (n 5 70) and (2) nonuniversity level (n 5 77). Assumptions for normality, linearity, and homoscedasticity of residuals were met and no outliers were found using p ! 0.001 criterion for Mahalanobis distance. R was not signi®cantly diåerent from zero ( p ! 0.05) after step onewith the entry of age and step 2 with the entry of education. After step 3 with age, education, and gender in the equation R 5 0.257, F (3, 143) 5 3.37, p ! 0.05. The addition of gender to the equation resulted in a signi®cant increment in R# ; R# 5 0.066 (adjusted R# 5 0.046), Finc (1,143) 5 7.21, p ! 0.01). Thus, nearly ®ve percent of the variance in self-perceived communicative ability can be accounted for by the gender of the informant in the current sample. Within this sample neither age nor education, together or separately, accounted for signi®cant amounts of variance in self-perceived communicative ability. Construct validity : factor analytic results Construct validity was examined using a principal component factor analytic procedure. This procedure was completed only on the self-report data (n 5 147), as the sample size for close others was not considered adequate. Comrey and Lee (1992) suggestthat for factor analysis sample sizes of 50 are very poor,100 are poor, 200 are fair and 300 are good. Thus, it should be noted that even our sample size
La Trobe communication questionnaire
263
Table 7. Factor loadings, communalities (h2) and percents of variance for principal factors extraction and varimax rotation on LCQ items Item (Original constructa )
Fb
26. 18. 08. 21. 17. 19. 11. 28. 23. 02. 05. 04. 07. 16. 20. 14. 27. 15. 24. 25. 03. 01. 13. 12. 29.
0.77 0.74 0.55 0.52 0.43
"
Thinking of things to say (Rel) Getting started (Cog) Speak to slowly (Rate) Change speech style (Rel) Trouble using tone of voice (Man) Keep track of main details (Cog) Know when to talk and listen (Man) Give accurate information (Quant) Put ideas together logically (Man) Use a lot of vague words (Quant) Time to think before answer (Man) Switch topic too quickly (Rel) Di¬culty thinking of words (Cog) False starts (Man) Unconnected answers (Rel) Need repetition (Quant) Answer without thinking (Cog) Give incorrect information (Qual) Allow wrong assumptions (Qual) Talk too long (Quant) Go over and over same ground (Quant) Leave out important details (Quant) Di¬culty in group conversations (Cog) Sidetracked by irrelevant parts (Cog) Lose track in noise (Cog) Percent of variance
F #
F
F
$
%
F &
F ’
0.73 0.69 0.63 0.60 0.70 0.66 0.53 0.42 0.73 0.62 0.57 0.48 0.75 0.63 0.61 0.59
20.1
8.0
6.6
4.9
4.9
0.73 0.48 0.45 0.45 4.5
h# 0.67 0.64 0.68 0.60 0.58 0.72 0.64 0.64 0.68 0.60 0.66 0.42 0.54 0.71 0.70 0.55 0.65 0.63 0.71 0.71 0.58 0.65 0.60 0.65 0.63
Rel 5 Relation ; Cog 5 Cognitive; Man 5 Manner; Quant 5 Quantity ; Qual 5 Quality. Factor labels : F Conversational tone; F Conversational eåectiveness; F Conversational ¯ow; " # $ F Conversational engagement; F Conversational } partner sensitivity ; F Conversational focus. a
b
%
&
’
for self-report is somewhat small. However, inspection of the correlation matrix revealed more than 40 correlations in excess of 0.30, including several in excess of 0.40 and 0.50 indicating that the correlation matrix obtained from our sample was likely to be factorable. An orthogonalVarimax rotation and scree plot examination of eigenvalues (Tabachnick and Fidell 1996) revealed that the optimal solution would involve six factors which together accounted for 48.9 % of the variance. To justify inclusion of items on individual factors a two-step decision rule was established (Tabachnick and Fidell 1996). First, only items with a factor loading of 0.40 (16 % of variance) or greater would be retained. The second rule was established for items loading on more than one factor. An item was retained on a factor if its loading was at least 0.10 greater than its loading on any other factor. Under these rules, the six factor solution comprised 25 of the 30 items. The ®ve items that did not meet one or both of the selection criteria were items 6, 9, 10, 22, and 30. The factor loadings, commonalities (h# ), and percents of variance for the six factor solution are shown in Table 7. Variables are ordered and groupedby size of loading to facilitate interpretation. Loadings under 0.40 are not shown. All of the factors included items from at least two of the Grician maxims and} or the cognitive construct used to guide the original item selection. The following interpretive
J. M. Douglas et al.
264
labels are suggested for each factor : factor 1-conversational tone, factor 2conversational eåectiveness, factor 3-conversational ¯ow, factor 4-conversational engagement, factor 5-conversational (partner) sensitivity, and factor 6-conversational attention} focus. In the label for the ®rst factor, we have applied the term tone to represent the degree of vigour, responsiveness and variation that an individual employs in conversation. Low conversational tone or a high frequency of di¬culties on this factor is indicative of an individual who speaks slowly, has di¬culty thinking of things to say, getting started, changing their speech style, and using their tone of voice in conversation. Poor conversational eåectiveness (factor 2) is consistent with frequent di¬culties keeping track of the main details in conversation, knowing when to talk and when to listen, and di¬culties being accurate and putting ideas together in a logical way. Items loading on factor 3, conversational ¯ow, included the use of vague words, word ®nding di¬culties, needing time to think before answering, and poor topic maintenance. Conversation engagement (factor 4) is re¯ected by items measuring revision behaviours, the need for repetition and inappropriateresponses.Factor 5 appears to relate to conversational or partner sensitivity. Here items involve the Grician maxims of quality and quantity. Items re¯ecting di¬culties with conversational sensitivity include giving information that is not correct, allowing conversational partners to assume wrong impressions, carrying on talking too long, and going over and over the same ground in conversation. Finally, the items loading on factor 6 appeared to be associated with conversational attention or focus and included di¬culty following groupconversations,losing track of conversationsin noise, getting side-tracked by irrelevant information and leaving out important details. Discussion The results of the present study indicate that the LCQ is a reliable measure of communicative ability in normal young adults who were primarily selected to act as a comparison group for young adults who sustain TBI. Thus, the primary participants were young with a mean age of 20 years. Further, as evidenced by father’s occupation, the socio-economic background of the majority of the participants (58% of females and 71% of males) was non-professional. It is interesting to note that 22 % of the original sample recruited for the study were excluded on the basis of having suåered a head injury that produced loss of consciousness or concussion. The high incidence of such injury in the population we sampled demonstrates to some degree the eåectiveness of our recruitment procedures to re¯ect demographic characteristics associated with a high incidence of TBI in the general population. Content reliability coe¬cients in the range of 0.85 and above indicated that less than 15% of the variance in questionnaire scores for primary subjects and close others was attributable to error and} or unknown constructs. Item-scale correlations showed a moderate degree of homogeneity in the behaviours sampled by the items of the questionnaire. Test-retest reliability for self-report over 8 weeks was acceptable with a coe¬cient of 0.75. However, the test-retest reliability coe¬cient for close other reports was markedly lower and disappointingat 0.48. A potential cause of this low correlation between the close other scores over the testretest interval is the possibility that the close other form was not completed by the
La Trobe communication questionnaire
265
same individual on both occasions. Thus, the apparently poor temporal stability of close other reports may re¯ect a change in informants for some} all participants from the ®rst to the second administration of the questionnaire. Unfortunately, the survey design of the study prevented the investigators from having direct contact with nominated close others and ensuring that the same individual completed the questionnaire with full knowledge of the importance of accuracy. Acceptable testretest reliability for close others will need to be established in future studies. Temporal stability for close others may be evaluated more readily for chronic clinical populations where investigators have direct contact with those relatives whose perceptions are being measured. Importantly, the LCQ was found to reliably measure self-perceived communicative ability independent of social desirability in¯uences and the education and age range sampled. All three variables shared less than one percent of the variance with LCQ total scores. With respect to the eåect of age on LCQ scores, it is important to remember that participants in this study were selected within a restricted age range (16±39 years). Thus, it is possible, even likely, that an age eåect may become apparent with extension of the age range to include middle-aged and elderly participants. Furthermore, although pleasing from a discriminant validity perspective, the ®nding that education did not account for a signi®cant proportion of variance in LCQ scores must be interpreted with caution. A simple dichotomous classi®cation of university versus non-universityeducation was used to explore the predictive ability of education in the sample. The vast majority of participants categorized as university level were ®rst or second year undergraduates.While the non-university group contained a large number of individuals who attended trade school and worked full-time. Thus, the real educational diåerence represented by these two groups may in fact be very small. Both the broad categorization of education as well as the nature of the subject pool may well have masked an education eåect. Further investigation across a wider educational range is necessary to clarify the role of education in self-perception of communicative ability. Unlike social desirability, age, and education, gender did account for a signi®cant, although small percentage (5%) of the variance in LCQ scores for normal young adults. Females perceived themselves to have signi®cantly less frequent di¬culties with overall communication than did males. However, signi®cant diåerences between males and females were identi®ed on only two of the 30 items. Males perceived themselves as having signi®cantly more frequent di¬culties with changing their speech style to suit communication situations and with keeping track of details in conversational exchanges. Both items may re¯ect gender-speci®c speech style which has been investigated by previous researchers (e.g. Crawford and Cha¬n 1987, Furrow and Moore 1990, Martin et al. 1990, Rubin and Nelson 1983, Spender 1981). On the whole, our results indicate that normal young adults regard themselves as reasonably competent communicators. On a scale where `1’ represents a selfperception of little or no di¬culty and `4’ represents a self-perception of frequent di¬culty, the most common self-perception among young adults is of being about a `1.6 ’, that is, a perception of experiencing communication problems somewhere between `rarely ’ and `sometimes’. Of the thirty items sampled, only seven were reported as causing problems at or around a rating of `sometimes’. Of these seven items, three arose from the cognitive domain of the LCQ, one from the construct of rate, and the remaining three represented one each of Grice’s quantity, quality,
J. M. Douglas et al.
266
and relation maxims. There is no apparent perception of di¬culty with the conversational constructof manner. Thus, these normal young adults perceive few di¬culties with their communicative ability. Whilst the young adults in our study had a relatively good opinion of their communicative ability, the opinions of their close others were even more positive. Overall, total scores indicated that young adults perceived signi®cantly more di¬culties in their own communication than did their relatives or friends. On the ten items where signi®cant diåerences were identi®ed, this diåerence was always in the same direction. That is, primary subjects reported more frequent di¬culties than were perceived by their close others. Such heightened self-awareness of di¬culty is not surprisingwhen the nature and level of the di¬culties experienced are considered. Mild di¬culties with word ®nding, getting conversations started, putting ideas together logically or losing track in conversations may well be experienced, and compensated for, by normal individuals without any knowledge of the di¬culty or the compensatory strategy on the part of their conversational partners. Consequently, an individual’s subjective experience of communication di¬culty is not always realized as a di¬culty perceived by close others. Essentially, it is not surprisingthat individuals may well be more aware of their own di¬culties and perhaps more critical of their own abilities than others. It is interesting to note that a reversal of this pattern has been reported following severe TBI. Using the LCQ, McNeill- Brown and Douglas (1997) found that adults with severe TBI, less than one year postinjury, reported signi®cantly fewer communication di¬culties than were perceived by their relatives and rehabilitation workers. The clinical signi®cance of this ®nding is highlighted when compared to the pattern obtained for normal young adults in our present study. Principal component factor analytic techniques delineated six groups of items with similar content representing diåerent factors. Twenty-®ve items loaded on six factors. Inspectionof the items loading on each factor indicated that the underlying factor structure re¯ected diåerent aspects of conversation or conversational style. None of the factors re¯ected a single Grician maxim but rather included items from at least two of the Grician constructs and} or the cognitive construct. We have labelled the six factors to re¯ect item content as follows : conversational tone, conversational eåectiveness, conversational ¯ow, conversational engagement, conversational (partner) sensitivity, and conversational focus} attention. Conclusions and implications for further research Our evaluation of the LCQ has shown it to be a reliable means of measuring self and close other perceptions of communicative ability in young adults. The present investigation has focussed on normal functioning and provides data with which to compare the perceptions of adults with TBI and their close others. Already studies involving adults with severe TBI in both the early post-injury period (McNeillBrown and Douglas 1997) and more than two years postinjury (Snow et al. 1999) have supported the clinical utility of the LCQ. In addition, the LCQ may well prove useful for measuring perceived communicative ability in older adults and clinical populationsother than TBI including those with right hemisphere damage and probable dementia. Work extending the age range of the LCQ and investigating possible age-related diåerences in perceived communicative ability is currently underway. Future clinical studies could include comparisons of self-
La Trobe communication questionnaire
267
perceptions with clinicians’ and relatives’ ratings. Convergentvalidity of the LCQ will also need to be addressed.Finally, the utility of the LCQ in predicting outcome and documenting the clinical course of communication disorders is worthy of investigation. References Allen, C. C. and Ruff, R. M. 1990, Self-rating versus neuropsychological performance of moderate versus severe head injured patients. Brain Injury, 4, 7±17. Anastasi, A. 1982, Psychological Testing (New York: MacMillan). Cavallo, M. M., Kay, T. and Ezrachi, O. 1992, Problems and changes after traumatic brain injury : diåering perceptions within and between families. Brain Injury, 6, 327±335. Chelune, G. J., Heaton, R. K. and Lehman, R. A. 1986, Relation of neuropsychological and personality test results to patients’ complaints of disability. In G. Goldstein and R. E. Tarter (eds) Advances in Clinical Neuropsychology, Vol 3, (New York: Plenum Press), pp. 95±126. Coelho, C. A., Liles, B. Z. and Duffy, R. J. 1991, Discourse analysis with closed head injured adults : evidence for diåering patterns of de®cit. Archives of Physical Medicine and Rehabilitation , 72, 465±468. Comrey, A. L. and Lee, H. B. 1992, A First Course in Factor Analysis , second edition (New Jersey: Erlbaum). Crawford, M. and Chaffin, R. 1987, Eåects of gender and topic on speech style. Journal of Psycholinguistic Research, 16, 83±89. Crowne, D. P. and Marlowe, D. 1960, A new scale of social desirability independent of psychopathology. Journal of Clinical and Consulting Psychology, 24, 349±354. Damico, J. S. 1985, Clinical discourse analysis : a functional approach to language assessment. In C. S. Simon (ed.) Communication Skills and Classroom Success (London: Taylor & Francis), pp. 165±203. DePompeii, R. and Zarskii, J. J. 1989, Families, head injury, and cognitive-communicative impairments : issues for family counselling. Topics in Language Disorders, 9, 78±89. Diller, L. and Gordon, W. A. 1981, Interventions for cognitive de®cits in brain injured adults. Journal of Consulting and Clinical Psychology, 49, 822±834. Douglas, J. 1994, Indicators of long-term family functioning following severe traumatic brain injury. Unpublished doctoral dissertation, University of Victoria, British Columbia. Ehrlich, J. and Barry, P. 1989, Rating communication behaviours in the head-injured adult. Brain Injury, 3, 193±198. Elsass, L. and Kinsella, G. 1987, Social integration after severe closed head injury. Psychological Medicine, 17, 67±78. Enderby, P. 1997, Therapy Outcome Measures : Speech Language Pathology (San Diego : Singular). Fordyce, D. J. and Roueche, J. R. 1986, Changes in perspectives of disability among patients, staå, and relatives during rehabilitation of brain injury. Rehabilitation Psychology, 31, 217±229. Furrow, D. and Moore, C. 1990, Gender diåerentiating terms expressing certainty. Journal of Psycholinguistic Research, 19, 375±384. Gillies, S. and Douglas, J. 1990, Perceptions of communication by an individual with closed head injury and his close relative. Unpublished clinical research project, La Trobe University, Melbourne. Goldstein, G. and McCue, M. 1995, Diåerences between patient and informant functional outcome ratings in head-injured individuals. International Journal of Rehabilitation and Health, 1, 23±35. Godfrey, H. P., Partridge, F. M. and Knight, R. G. 1993, Course of insight disorder and emotional dysfunction following closed head injury : A controlled cross-sectional follow-up study. Journal of Clinical and Experimental Neuropsychology, 15, 503±515. Grice, H. P. 1975, Logic in conversation. In P. Cole and P. Morgan (eds) Studies in Syntax and Semantics, Vol. 3 (New York: Academic Press), pp. 41±58. Hagen, C. 1984, Languagedisorders in head trauma. In A. Holland (ed.) Language Disorders in Adults (San Diego : College Hill Press), pp. 245±280. Hartley, L. L. and Jensen, P. J. 1992, Three discourse pro®les of closed head injury speakers: Theoretical and clinical implications. Brain Injury, 6, 271±281. Hartley, L. L. and Levin, H. S. 1990, Linguistic de®cits after closed head injury : A current appraisal. Aphasiology, 4, 353±370.
268
J. M. Douglas et al.
Kreutzer, J., Marwitz, J., Seel, R. and Serio, C. 1996, Validation of a neurobehavioural functioning inventory for adults with traumatic brain injury. Archives of Physical Medicine and Rehabilitation, 77, 116±124. Martin, C., Wood, C. and Little, J. 1990, The development of gender stereotype components. Child Development, 61, 1891±1904. McKinlay, W. W. and Brooks, D. N. 1984, Methodological problems in assessing psychosocial recovery following severe head injury. Journal of Clinical Neuropsychology, 6, 87±99. McKinlay, W. W., Brooks, D. N., Bond, M. R., Martinage, D. P. and Marshall, M. M. 1981, The short-term outcome of severe blunt head injury as reported by relatives of the injured persons. Journal of Neurology, Neurosurgery, and Psychiatry, 44, 527±533. McNeill-Brown, D. L. and Douglas, J. M. 1997, Perceptions of communication skills in severely brain-injured adults. In J. Ponsford, V. Anderson and P. Snow (eds) International Perspectives on Traumatic Brain Injury. Proceedings of the Fifth International Association for the Study of Traumatic Brain Injury Conference, Melbourne, Australia, November. (Brisbane: Australian Academic Press), pp. 247±250. Prigatano, G. P. 1991, Disturbances of self-awareness of de®cit after traumatic brain injury. In G. P. Prigatano and D. Schacter (eds) Awareness of De®cit after Brain Injury (New York: Oxford University Press), pp. 111±126. Prigitano, G. P. and Altman, I. M. 1990, Impaired awareness of behavioural limitations after brain injury. Archives of Physical Medicine and Rehabilitation , 71, 1058±1064. Prigitano, G. P., Altman, I. M. and O’Brien, K. P. 1990, Behavioural limitations that traumaticbrain-injured patients tend to underestimate. The Clinical Neuropsychologist , 4, 163±176. Prigitano, G. P. and Fordyce, D. J. 1986, Cognitive dysfunction and psychosocial adjustment after brain injury. In G. P. Prigatano (ed.) Neuropsychological Rehabilitation after Brain Injury (Baltimore : John Hopkins University Press), pp. 1±17. Romano, M. D. 1974, Family response to traumatic head injury. Scandinavian Journal of Rehabilitation Medicine, 6, 1±4. Rubin, D. and Nelson, M. 1983, Multiple determinants of a stigmatized speech style : Women’s language, powerless language, or everyone’s language. Language and Speech, 26, 273±288. Selltiz, C., Wrightsman, L. S. and Cook, S. W. 1976, Research Methods in Social Relations (New York: Holt, Rinehart & Winston). Snow, P., Douglas, J. and Ponsford, J. 1995, Discourse assessment following traumatic brain injury : a pilot study examining some demographic and methodological issues. Aphasiology, 9, 365±380. Snow, P., Douglas, J. and Ponsford, J. 1999, Self} close other-report and communication skills following severe traumatic brain injury. Paper presented at the 22nd Annual Brain Impairment conference, Sydney, Australia, April. Spender, D. 1981, Man Made Language (London: Routledge & Kegan Paul). Strahan, R. and Gerbasi, K. 1972, Short, homogeneous versions of the Marlowe-Crowne Social Desirability Scale. Journal of Clinical Psychology, 28, 191±193. Tabachnick, B. and Fidell, S. 1996, Using Multivariate Statistics (New York: Harper Collins). Tanner, D. C. and Gerstenberger, D. L. 1988, The grief response in neuropathologies of speech and language. Aphasiology, 2, 79±84. Tyerman, A. and Humphrey, M. 1984, Changes in self-concept following severe head injury. International Journal of Rehabilitation Research, 7, 11±23.
