Effects of Lateralized Tasks on Unilateral Neglect Mter ...

position on grip and key pinch strength. Journal of Hand Surgery, lOA,694-697. Mathiowetz, v., Weber, K., Volland, G., & Kashman, N. (1984). Reliability and validity of hand strength evaluation. Journal of Hand Surgery, 9A, 222-226. Mathiowetz, v., Wiemer, D. M., & Federman, S. M. (1986). Grip and pinch strength: Norms for 6- to 19-year-olds. American Journal of Occupational T7lerapy, 40, 705-711. Mitchell, D. M., & Fries, J. F. (1982). An analysis of the American Rheumatism Association criteria for rheumatoid arthritis. Ar thritis f:t Rheumatism, 25, 481-488. Myers, D. B., Grennan, D. M., & Palmer, D. G. (1980). Hand grip function in patients with rheumatoid arthritis. Archives of Physical Medicine & Rehabilitation, 61, 369-373. Pearson, R., MacKinnon, M. J. , Meek, A. P., Myers, D. B., & Palmer, D. G. (1982). Diurnal and sequential grip function in normal subjects and effects of temperature change and exercise of the forearm on grip function in patients with rheumatoid arthritis and in normal controls. Scandinavian Journal of Rheumatology, 11, 113-118. Perry, F. J., & Bevin, G. A. (1974). Evaluation procedures for patients with hand injuries. Physical Therapy, 54, 593-598. Schmidt, R. T., & Toews, J. V. (1970). Grip strength as measure by the Jamar dynamometer. Archives of Physical Medicine & Rehabilitation, 51, 321-327. Sheehan, N. J., Sheldon, F., & Marks, D. (1983). Grip strength and torquometry in the assessment of hand function in patients with rheumatoid arthritis. British Journal of Rheumatology, 22, 158-164. Smith, R. 0., & Benge, M. W. (1985). Pinch and grasp strength: Standardization of terminology and protocol. American Journal of Occupational Therapy, 39, 531-535. Wainerdi, H. R. (1950). Simple ergometers for measuring the strength of the hand (grip). Journal of the American Medical Associa tion, 144, 619-620. Wright, V. (1959). Some observations on diurnal variation of grip. Clinical Science, 18, 17-23.

Effects of Lateralized Tasks on

Unilateral Neglect Mter Right

Cerebral Vascular Accident

Sharon A. Cennak, Catherine A. Trombly,

Joann Hausse~ Anne M. Tieman

Key words: hemi-inattention • visuospatial inattention cognitive-perceptual

Abstract This study examined Whether activities designed to stimulate the right hemisphere of the brain resulted in decreased neglect in patients with right cerebral vascular accident (CVA) and unilateral neglect (UN) and, con versely, Whether activities designed to stimulate the left hemisphere re sulted in increased left neglect. An alternating treatment, single subject deSign was used with five subjects, ages 57 to 74, Who demonstrated neglect on both the Schenkenberg Line Bisection Test and the behavioral subtest of the Behavioral Inattention Test. Each subject received 8 days of baseline measures (ScJlenkenberg Line Bisection Test) and 10 days of treatment, dUring which the subjects were alternately engaged in the groups of tasks

Sharon A. Cermak, EdD, 0fR/L, is an Associate Professor of Occupational Therapy at Boston University, Sargent College, 635 Commonwealth Ave nue, Boston, MA 02215. Catherine A. Trombly, MA, OfR/L, is a Professor of Occupational Therapy at Boston University, Sargent College. Joann Hausser, MS, OfR/L, is an Assistant Professor of Occupational Therapy, Eastern Kentucky University, Richmond, Ky. Anne M. Tiernan, MS, OfR/L, is an occupational therapy consultant, Jefferson Hospital, Port Townsend, Wash. This manuscript was accepted under the editorship of Kenneth J. Otlen bacher and Betty R. Hasselkus.

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The Occupational Therapy Journal of Research

September/October 1991, Volume 11, Number 5

271

a.

intended to arouse a particular hemisphere, followed by six to eight baseline measures. Line bisection scores were taken after each treatment. The significance ofchange in UN after either group ofactivities was determined by visual inspection and semi-statistical analysis using tlte two standard deviation band method. The findings did not support the hypotheses. ThJo subjects demonstrated no significant change after either treatment phase; one subject showed a significant decrease in neglect after both phases of treatment; one subject showed a significant decrease in neglect after activities designed to stimulate tlte right hemisphere but no change after activities to facilitate the left hemisphere; and one subject showed a signifi cant increase in neglect after both types of treatment. Results are discussed in terms of severity of impairment, fatigue effect, spontaneous recovery, and the adequacy of the tasks to differentially activate a single hemisphere.

U

nilateral neglect (UN) is described as the failure to report, respond, or orient to novel or meaningful stimuli presented to the side opposite a brain lesion (Heilman, 1979; Heilman, Watson, & Valenstein, 1985). The most common cause is cerebral vascular accident (CVA) following lesions in the right parietal lobe or tem poro-parietal-occipital junction. Depending on the diagnostic meas ures used, there is neglect in 30% to 90% of the cases of right-brain damage (RBD) (Schenkenberg, Bradford, & Ajax, 1980). Reports of incidence of UN in left-brain damage (LBD) are more variable, possibly because the presence of language deficits has discouraged or confounded testing (Ogden, 1987). According to Heilman and Watson (1977), neglect exists in LBD but is less common and less severe. The symptoms vary according to the severity of the neglect. Mild neglect manifests itself as extinction to double simultaneous stimu lation (Heilman & Watson, 1977), while severe neglect manifests in such total disregard of left visual space that it interferes with the patient's ability to eat from the left side of the plate or dress the left side of the body (Fox, 1983; Gordon et al., 1985). Patients demonstrating unilateral neglect have poorer prognoses in rehabilitation (Denes, Semenza, Stoppa, & Lis, 1982; Kaplan & Hier, 1982; Kotila, Niemi, & Laaksonen, 1986; Weinberg et aI., 1977). Kinsella and Ford (1980, 1985) found that RBD patients with neglect scored significantly lower on measures of activities of daily living (ADLs) than RBD patients without neglect. Also, although neuropsychological testing 18 months post stroke showed consider able improvement or even recovery from UN, those patients who had shown UN at initial assessment continued to be low achievers in complex functional tasks. Kotila et al. (1986) found that of 52 RBD

272


patients studied 3 months post stroke, only 25% of patients with neglect were independent compared to 80% of those patients with out neglect; at 4 years post stroke, 50% of patients with neglect or inattention were dependent in ADLs compared to only 6% of pa tients without neglect or inattention. Clinicians treating stroke patients frequently are confronted by the problems of UN. Therapists have not had the guidance of a well-developed body of empirical knowledge or a cohesive theoreti cal foundation on which to base their treatment of patients with UN. Although various treatment approaches have been designed to remediate neglect, ranging from tactile stimulation (Anderson & Choy, 1970), to visual scanning exercises (Weinberg et aI., 1977), to more comprehensive programs (Gordon et aI., 1985), reports of effectiveness of these treatments are sparse (see Lin & Cermak, in press). Because the mechanisms underlying unilateral neglect are not fully understood,' it is difficult to design treatments directed to remediating the underlying nature of the specific deficits. Van Deusen (1983) and Pelland (1986) have emphasized the need for occupational therapists not only to evaluate the effectiveness of eXisting treatments for unilateral neglect, but also to develop new treatments that reflect current theories of neglect. Two theories postulated to explain neglect relate to attentional mechanisms. One of the most widely supported, "the attention arousal theory," proposes that hemi-inattention results from a uni lateral lesion anywhere in the corticolimbic reticular formation loop (Heilman et aI., 1985); central in this loop is the mesencephalic reticular formation (MRF), a subcortical structure associated with behavioral arousal (Heilman, Bowers, Valenstein, & Watson, 1987). The loop also contains the nucleus reticularis of the thalamus (NRT), which inhibits thalamic relay of sensory information to the cortex. Normally, the MRF inhibits the NRT, thus allOWing thalamic trans mission to the cerebral cortex. However, Heilman et al. (1985) propose that after a lesion to the MRF, unilateral inattention (or neglect) will occur either because loss of inhibition of the NRT by the MRF decreases thalamic transmission of sensory input to the cortex, or because the MRF does not prepare the cortex for sensory process ing, or both. Also contained in the MRF loop is the inferior parietal lobe, which has connections to the frontal lobe and limbic system. These areas play critical roles in attention. Heilman et al. (1985) further propose that a lesion in the inferior parietal lobe can also result in inattention. In summary, the attention-arousal theory ex plains unilateral neglect in terms of a lesion within the corticolimbic reticular formation loop.


273

The second theory, the"interhemispheric interaction and inhibition theory," describes unilateral neglect as an imbalance in brain activa tion. Kinsbourne (1987), the major proponent of this theory, proposes that unilateral neglect does not result from an attentional deficit but rather from an attentional bias, that is, an imbalance in the system that controls lateral orientation and action. Kinsbourne (1977, 1987) states that although each hemisphere mediates attention in the contralateral hemispatial field (HSF), the tendency to orient to the right is stronger than the tendency to orient to the left. This would account for the higher incidence of neglect in RBD than in LBD patients. A major tenet of Kinsbourne's theory is that each hemisphere's attentional mecha nisms interact with and are influenced by the cognitive and perceptual functions mediated by that hemisphere (Kinsbourne, 1973, 1975, 1977). Kinsbourne suggested that the activation of the left hemisphere during language functions shifts attention to the right HSE and that activation of the right hemisphere during spatial functions shifts attention to the left HSE Some studies have indicated that perform ance of lateralized tasks in normals is improved by presenting the stimulus material in the contralateral field (Barton, Goodglass, & Shai, 1965; Geffen, Brads~aw, & Wallace, 1971; Heilman et al., 1987). Nor mally, the hemispheres maintain a mutually inhibitory balance with respect to attention. With injury to one hemisphere, the balance is lost and the intact hemisphere becomes uninhibited or facilitated; it, in tum, exerts a greater inhibition on the damaged hemisphere. Thus, while the attention-arousal theory describes left unilateral neglect in terms of inactivation of the right hemisphere after a right cerebral vascular accident, the hemispheric interaction-inhibition theory de scribes it in terms of overactivation of the left hemisphere. We may infer from these theories that stimuli presented on the contralesioned side of the body should increase activity of the lesioned hemisphere and ultimately result in decreased neglect. Also, con versely, it can be inferred that presentation of stimuli to facilitate the intact hemisphere should increase neglect of the contralesional HSE The purpose of this study was to test the following two hypotheses in patients with RBD and UN: a) After treatment designed to activate the right hemisphere, decreased left-sided neglect will result, as evi denced by lower scores on the Schenkenberg Line Bisection Test (Schenkenberg et al., 1980); and b) After treatment designed to activate the left hemisphere, increased left-sided neglect will occur, as evi denced by higher scores on the Schenkenberg Line Bisection Test.

274


Method Design An alternating treatment, single system design was used, because it is well-suited to compare the possibly divergent effects of two treatments in a clinical setting (Ottenbacher, 1986). Alternating treat ment phases control for intervening variables such as emotional state, motivational fluctuations, physical status, and other factors that affect performance. A baseline period (phase A) preceded and followed the two treatment phases (phases B and C). Phase B consisted of activities designed to arouse the right hemisphere; phase C consisted of activities designed to arouse the left hemisphere. During the initial phase A, the Schenkenberg Line Bisection Test was performed daily at consistent times until a stable baseline occurred or 8 data points were recorded (Kazdin, 1982). Ten days of treatment followed, designated as phases Band C. The two treat ments were alternated in the following pattern: CBBBC; BCCCH. While controlling for intervening variables by frequently alternating the treatment phases, repeating the same treatment for three consec utive days allowed for any additive effects to be observed. During phases B and C, treatment was immediately followed by the Schenk enberg test. After the 10 days of treatment, the Schenkenberg test continued to be consistently administered for the 8 days of the final baseline period (A2). When possible, a 6-month follow-up retest was completed.

Subjects Five subjects (three males and two females) who met the follow ing criteria were recruited: English-speaking, younger than 75 years of age, within 4 months post right cerebral vascular accident, medi cally stable, right-handed, literate, and not trained musicians. Only subjects who scored greater than 3 standard deviations from the mean on the Schenkenberg Line Bisection Test and 14 or more errors on the behavioral subtest of the Behavioral Inattention Test (BIT) (Wilson, Cockburn, & Halligan, 1987a) were considered for this study. Table 1 shows initial and mean initial baseline scores for all subjects. The three subjects whose mean baseline scores on the Schenkenberg test, the dependent measure, were similar are dis cussed in depth and the results of the other two subjects are summa-


275

Table 1 Schenkenberg Line Bisection Test Scores for Each Subject

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PhaseC

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15.1 7.9 14.1 20.5 4.6

16.0 8.2 16.1 19.9 3.5

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hemianopsia, moderate left neglect, and moderate left hemiparesis and hemisensory loss consistent with a right middle cerebral artery distribution infarct. Neuropsychological testing indicated right hemisphere dysfunction, with anterior deficits greater than poste rior. Flat affect, dysphoric mood, decreased inhibition, increased impulsivity, moderately decreased visual spatial organization, mod erate impersistence, moderately decreased new verbal learning with limited insight, and mildly decreased concentration were noted. The occupational therapist found a moderate left neglect during functional activities, moderate assistance required for all ADLs, and moderately decreased overall strength, endurance, and coordina tion of the left upper extremity. In physical therapy, minimal assis tance with transfers and ambulation was needed. The speech language pathologist found mild dysarthria, mild perseveration deficits, moderate-severe deficits in reading, pragmatics, and pros ody, maximal cuing needed for functional writing, severely de creased organizational skills, and severely decreased attention. The subject was very cooperative during therapies and throughout the study, but was also frustrated because of her lack of independence. Subject 3 was a 57-year-old man with a history of hypertension and adult-onset diabetes. He had been admitted to the rehabilitation hospital on the 10th day post CVA, secondary to complete occlusion of the right internal carotid artery. He became a subject in the study at 13 weeks post evA. Visual screening indicated that subject 3 had hemianopsia and was unable to fixate on a near target longer than 2 seconds or a on distant target for longer than 4 seconds. Ocular pursuits were characterized by excessive blinking and saccade-like eye movement to the left. This subject extinguished auditory stimuli on the left with double simultaneous stimulation. He did not re spond to light touch on his left arm. Subject 3 also exhibited left hemiparesis, right foot drop secondary to diabetic peripheral neu ropathy, impulsiveness, agitation, and impairments in sustained attention, body awareness, spatial perception, cognitive flexibility, abstract reasoning, insight, and safety awareness. He was dis charged during the final baseline phase to a convalescent center where he was seen until the completion of the study. Subjects 4 and 5 differed from the other three subjects in severity of neglect. Subject 4 was a 74-year-old male who started the study 8.5 weeks post stroke and had the most severe neglect of aU the patients as evidenced by an initial Schenkenberg score of 18.4 stan dard deviations from the mean and BIT scores of 24 in the conven tional subtest and 0 in the behavioral subtest. His usual sitting position involved neck rotation 50 to the right of midline. This subject exhibited severe left hemiparesis, impulsiveness, decreased

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The Occupational TIlerapy Journal of Research

sensation throughout the left side, and impainnents in arousal, spatial perception, cognitive processing, and safety awareness. Subject 5 was a 70-year-old woman who started the study 2 weeks post stroke and had relatively minimal neglect in comparison to the other subjects' initial scores (Schenkenberg • 5.9 standard devia tions from the mean; BIT conventional .. 138; BIT behavioral. 51). CT scan performed at the time of the CVA revealed a right parietal frontal infarct/ deep right middle cerebral artery infarct felt to be caused by an embolus from the internal carotid artery. No follow-up CT scan was done. Neurological testing revealed mild proximal left hemiparesis, moderate distal left hemiparesis, a right gaze prefer ence, no confrontation field defect, decreased response to double simultaneous stimulation in the auditory mode, and mild-moderate left neglect.

Instrumentation Instructions for administration and scoring the Schenkenberg Line Bisection Test were described by Schenkenberg et al. (1980). The test uses an 8.5- x ll-inch sheet of paper containing 20 lines of various lengths, which is taped to a table top with the midline of the paper at the SUbject's midline. The subject is asked to bisect each line with a mark as close to the center as possible. Normative data for elderly people (mean age 70.5 years) were collected in a study by Van Deusen (1983). The scores of the Schenkenberg test are the subject'S standard deviation from the mean of normal elderly indi viduals, with higher deviation scores indicating greater impairment. Schenkenberg et al. found test-retest correlation coefficients ranging from 0.84 to 0.93 with 60 CVA patients and 20 control hospital workers whose ages ranged from 18 to 85 years. Van Deusen reported lower test-retest reliability in a sample of 93 normal elderly 'people; Pearson product-moment correlation coefficients were 0.68 for left-placed lines and 0.66 for center lines. The BIT consists of two parts: one is a battery of six conventional subtests that have traditionally been used to assess unilateral visual neglect, and the other is a battery of nine behavioral subtests that simulate ADLs (Wilson et al., 1987a,b). The conventional subtest consists of six pencil and paper tasks: line crossing, letter cancella tion, star cancellation, figure and shape copying, line bisection, and representational drawing. This subtest was administered to provide a more thorough description of neglect. The behavioral subtest of the BIT assesses performance in the follOWing nine tasks: picture scanning, telephone dialing, menu reading, article reading, telling


279

and setting the time, coin sorting, address and sentence copying, map navigation, and card sorting. The BIT was standardized on 50 normal subjects in Great Britain and appears to have high inter-rater (.99), test-retest (.99), and parallel-form (.91) reliability (Wilson et al., 1987a,b). A score of 129, which is equal to 17 or more errors, is the cut-off score for the conventional subtest, and 67, which is equal to 14 or more errors, is the cut-off score for the behavioral subtest. Scores at or below these points are considered indicative of unilateral visual neglect. This test, which has been reviewed by Cermak and Hausser (1989), was selected because a measure of functional task performance was desired.

activity, a stereognosis task, the subject felt three-dimensional alpha bet letters attached to a cardboard backing. When the subject recog nized each letter, he verbally identified the letter and then named a word beginning with the letter. This activity continued for 5 min utes. The second activity was working a crossword puzzle of appro priate difficulty for 10 minutes, using the right hand for writing in the words. The crossword puzzle was placed in the right HSF. For the third task, the subject read aloud a short article of general interest and answered questions regarding it. The subject was in volved in this task for 5 minutes.

Data Analysis

Procedure All treatment took place in a distraction-free room with only the examiner and the subject present. The experimental interventions did not replace or interfere with any regularly scheduled therapies. In phase B, which was designed to activate the right hemisphere, the subject was reminded that this would be a quiet session with no talking and that questions would be answered after the session. The first activity was a stereognosis task for the left hand. The forms to be identified were those from the Manual Form Perception Test of the Sensory Integration and Praxis Test (Ayres, 1989) and were chosen because their abstract shapes were unlikely to be associated with names. If subjects were unable to manipulate the shapes secon dary to hemiparesis, the examiner assisted by forming the subject's fingers around the shapes. A visual display of the abstract forms was placed just to the left of the subject's midline, and the subject pointed with the right hand to the design being felt. The subject was in volved in this activity for 5 minutes. The second activity was assembling a jigsaw puzzle believed to be appropriate for the subject's cognitive-perceptual ability. The puzzle and its pieces were placed in the left HSE and the subject worked on it for 10 minutes. The picture of the completed puzzle was not shown to the subject to minimize possible language association. For the third task, the subject listened for 5 minutes to a tape recording of classical or jazz music played into the left ear. Classical and jazz rather than contemporary music was chosen to minimize verbal associations. Although each ear sends information from all its receptors to both hemispheres, a slight advantage via the contra lateral route has been reported (Springer & Deutsch, 1985). Phase C was designed to activate the left hemisphere. In the first

280


In single system designs, graphiC presentation and visual analysis have been the traditional methods of evaluating data (Ottenbacher, 1986). Although these methods have been challenged in recent years, graphiC analysis and visual inspection remain the most widely used and easily understood methods of data analysis for single system deSigns (Ottenbacher). However, Kazdin (1982) identified four situations in which statis tical analysis may be appropriate: when baseline data are unstable, when there is a relatively large degree of intrasubject variability in the treatment setting, during the initial stages of investigating a new intervention or treatment, or if it appears that small improvements not detectable by visual analysis may be significant. Because a new intervention was being examined in this study, statistical analysis supplemented the graphic analysis.

Results To reiterate, the hypotheses were that I) activities designed to

facilitate the right hemisphere would decrease neglect as evidenced by

a lower Schenkenberg score, and II) activities designed to facilitate the

left hemisphere would increase neglect. The two standard deviation

band method was used to analyze the data. This semistatistical ap

proach is used to analyze single system data when serial dependency

is not a factor (Ottenbacher, 1986). A lag-1 autocorrelation performed

on the data for each subject revealed no significant autocorrelation; in

other words, the data were neither serially dependent nor sequentially

correlated. When using the two standard deviation band method,

significance is achieved if two consecutive data points lie outside the

two standard deviation band imposed on the graph.

SLop/ember/October 1991, Volumc' 11, Number 5

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Subject 1 Neither hypothesis was supported for subject 1 (Figure 1). The data did not show significant change in unilateral neglect in either treatment phase, that is, no two consecutive data points fell outside the two standard deviation band during either Phase B or Phase C. Table 2 shows scores on the BIT. Upon completion of the study, this subject's scores on both the conventional and behavioral tests increased 7% and 17%, respectively, from the initial scores. On the 6-month retest, subject 1 demonstrated slight but continued im provement on the BIT and minimal change on the Schenkenberg Line Bisection Test (13.7 standard deviations from the mean as compared to the mean baseline score of 14.8).

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The line bisection scores for subject 2 supported hypothesis I; a significant decrease in line bisection scores is seen in phase B (Figure 2). However, subject 2 also demonstrated a significant decrease in line bisection scores in phase C. This is the opposite direction to that predicted in hypothesis II. Table 2 shows BIT results. Upon completion of the study, conven tional and behavioral subtest scores showed increases of 2% and 18% over initial scores. At the 6-month follow-up, these scores showed continued improvement as did the Schenkenberg score, which was 2.1 standard deviations from the mean as compared to the initial mean baseline score of 14.8 standard deviations from the mean.

of the study. Two standard deviation bands are extended across both treatment phases.

showed a change toward poorer performance (higher scores) during both types of treatment. For subject 5, phases B and C were not significantly different from baseline performance.

Discussion

The results for these subjects did not clearly support the hypothe ses. Table 1 shows mean standard deviation scores on the Schenken berg Line Bisection Test for subjects 4 and 5. Subject 4 actually

In general, results of this study do not support the hypotheses that activities designed to facilitate the right hemisphere would decrease neglect while activities designed to facilitate the left hemisphere would increase neglect. However, we felt it was valuable to publish for three reasons. First, knowing what works as well as what does not work is critical to developing valid clinical practice. Even non significant results contribute to our knowledge base. Second, the study is an example of theory-based research. Third, the project illustrates the use of single system design in a clinical setting. This research was part of an overall research program at the Neurobe havioral Rehabilitation Research Center, a center for scholarship and research at Boston University funded by the American Occupa tional Therapy Foundation and the American Occupational Therapy Association. We planned to conduct a pilot study (the five cases presented here) and then expand the project to involve clinicians collecting data from 15 additional cases. The clear lack of predicted

282


Subject 3 Neither hypothesis was supported by the data from subject 3 (Figure 3). Reassessment of this subject with the BIT showed a slight increase on the conventional test and a slight decrease on the behavioral test (Table 2).

Subjects 4 and 5


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treatment effects has indicated that we must rethink our treatment approaches. We cannot conclude that the theory on which these treatment activities are based is wrong, but we can say that the activities we selected did not have the predicted effect. Several factors should be considered in interpreting the results of this study. Activities were selected on the premise that each activated a certain hemisphere. However, lateralization of stimuli to one hemisphere and selective activation of that hemisphere may be largely a laboratory phenome non. That is not to say that each hemisphere is not specialized and superior to the other in processing certain tasks. Rather, laterality tests using tachistoscopic or dichotic presentation of material were designed to limit interhemispheric communication so that the abili ties of a single hemisphere could be compared to the abilities of the other. This is not the situation in the present study and it is probably not the situation in most complex tasks. Cerebral blood flow studies during different mental activities do show small but significant differences between the hemispheres (Risberg, Halsey, Wills, & Wilson, 1975); however complex tasks have typically involved in creased patterns of activation in many areas of both hemispheres (Lassen, Ingvar, & Skinhoj, 1978). Additionally, hemispheric specialization has been shown to vary with the type of strategy and the mode of response employed.

284

The Occupational T11erapy Journal of Research

Figure 3. Subject 3: Schenkenberg test scores throughout all phases of the study. Two standard deviation bands are extended across both treatment phases.

Experiments with split-brain subjects showed that both hemispheres could match pictures of objects but that the right hemisphere matched pictures by their appearance and the left hemisphere matched by function (Levy & Trevarthen, 1976). Similarly, studies of language processing in normal Japanese subjects found that right or left hemisphere dominance depended on the strategy used by a subject and whether the response was verbal or nonverbal (Sasan uma, !toh, Mori, & Kobayashi, 1977). In consideration of the previ ous points, selective activation of a specific hemisphere may be too complex to manipulate in a clinical setting. In addition, it was assumed that activities typically mediated by a particular hemisphere would facilitate or arouse that hemisphere in subjects whose arousal levels are decreased and that this arousal would be maintained immediately after performing these activities. It may be that facilitation of the targeted hemisphere did not Occur. In severely involved patients such as the subjects in this study, there may be such extensive damage to the right hemisphere that it cannot be activated enough to create the observable shift in attention pre dicted by Kinsbourne (1973, 1975, 1977, 1987). Alternatively, per haps the arousal effects Were not maintained beyond the duration of stimulus application. Another point to consider is applying research results from a normal population to an abnormal population. It was assumed in


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this study that the activities presented would produce the same effects in an abnormal population as they had in normal popula tions. To fully understand the results of this study, further research that looks specifically at the responses of subjects with unilateral neglect to each of the activities used in this study is needed. Specifi cally, regional cerebral blood flow or EEG studies with subjects demonstrating unilateral neglect and using tasks such as those used in this study might answer this question. Beyond these considerations, certain limitations in the design or in carrying out the experimental protocol may have affected internal validity. First, it was difficult to design and maintain a situation that did not potentially activate the left hemisphere. The right-handed motor responses that were necessary because of left hemiparesis may have activated the l~ft hemisphere so that it took conttol of the activities in both phases. Adherence to the "no talking" rule during treatment B was not well controlled in two subjects who tended to be hyperverbal and distractible. Kins bourne (1973) found that concurrent rehearsal of word lists (a left~brain activity) during visual discrimination tasks (a right brain activity) biased attention so that the best performance oc curred in the right visual field rather than the left visual field, which was superior without concurrent rehearsal of word lists. Further, activities were simplified and individualized so each subject could participate without becoming overly frustrated. For example, the protocol for treatment phase B Tequired that the jigsaw puzzle be placed in the left HSF to maximally activate the right hemisphere; however, neither subject 3 nor 4 could attend to the task in this position or in the midline position. Both were able to participate in the task only when it was placed in the right HSF. Such adjustments may have changed the hemisphere-specific nature of the task. It was also necessary to frequently assist subject 4 by applying compensatory strategies to enable him to perform the reading and writing tasks of treatment C. The combination of three activities using tactile, visual, and auditory modalities during a Single treatment was chosen be cause it was expected to be more powerful than anyone activity used alone. It is possible that if the outcome of one task was positive and the next was negative there would be no observable effect. Thus the design of the experiment did not allow for each task's effect to be identified. In addition, treatment may have lasted too long to maintain arousal levels. The combination of three activities in each treatment phase was proposed to continu ally activate the targeted hemisphere; it may be that the duration of the treatment instead resulted in decreased arousal and/ or

increased fatigue. The fatigue effect in neglect has been discussed by Fleet and Heilman (1986) who found in their study of five patients with neglect exacerbation of neglect in letter cancellation tasks after repeated administration of the tasks. It was also noted that repetitive trials reduced arousal and activation in normals (Fleet & Heilman). In looking at the present study, it may be that by performing the same tasks during each treatment phase the level of arousal was reduced and thus the likelihood of achieving the predicted treatment results also was reduced. It would be interesting to look at the subjects' responses to different tasks, or a different order of presentation of the same tasks. No other studies have looked at immediate results after a hemispheric-based treatment lasting 20 minutes, nor have any studies looked at sustained arousal levels after repetitive treat ments in patients with unilateral neglect. Results from studies of this kind could help explain the present findings. Because it was not clear why subjects 2 and 4 showed signifi cant changes, alternate explanations were considered. Neither sex, age, nor time post stroke appeared to be the explanatory variables. Data Were graphed sequentially to examine order and recovery effects; no consistent pattern was noted across subjects. However, the data for subject 2 suggest that recovery, rather than these particular treatments, explained the results. Kinsella and Ford (1985) found unilateral neglect present in 26% of stroke patients examined 1 month post stroke whereas only 13% of these same patients demonstrated neglect 1 month later. Similarly, Campbell and Oxbury (1976) found that of six patients de monstrating neglect when tested within 1 month post stroke, only two demonstrated neglect when tested at 6 months post stroke. Subject 4, who showed a significant deterioration in perform ance in both phases Band C, was the oldest subject and had the most severe neglect in this study. This subject generally had a decreased level of arousal and marked perseveration. In summary, neither right nor left hemisphere-specific tasks were clearly related to an immediate, significant change in the subjects' performance on the Schenkenberg test. These results do not support the use of lateralized tasks to activate the right hemisphere for the purpose of imprOVing UN, nor do they sup port the idea that left hemisphere-lateralized tasks worsen UN. However, many factors, such as lack of expected response to the individual activities or lack of sustained arousal, recovery, or fatigue may have affected the outcome of this study. When a new treatment fails to work, both the treatment itself and the theory or theories that support the approach must be analyzed. Occupa

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tional therapy for patients with unilateral left neglect will benefit from continued research in this complex and interesting area. References Anderson, E. K., & Choy, E. (1970). Parietal lobe syndromes in hemiplegia. American Journal of Occupational Therapy, 24, 13-18. Ayres, A J. (1989). TIle Sensory Integration and Praxis Tests. Los Angeles: Western Psychological Services. Barton, M. L., Goodglass, H., & Shai, A (1965). Differential recogni tion of tachistoscopically presented English and Hebrew words in right and left visual fields. Perceptual and Motor Skills, 21, 431-437. Campbell, D. C, & Oxbury. J. M. (1976). Recovery from unilateral visuo-spatial neglect? Cortex, 12, 303-312. Cermak,S., & Hausser, J. (1989). The Behavioral Inattention Test: A critical review. Physical and Occupational, Therapy in Geriatrics, 7, 43-53. Denes, G., Semenza, c. Stoppa, E., & Lis, A (1982). Unilateral spatial neglect and recovery from hemiplegia: A follow-up study. Brain, 105, 543-552.

fleet, W. S., & Heilman, K. M. (1986). The fatigue effect in hemispa tial neglect. Neurology, 36(Suppl. 1), 258. Fox, J. v. D. (1983). Unilateral neglect: Evaluation and treatment. Physical and Occupational TIlerapy in Geriatrics, 2(4), 5-15. Geffen, G., Bradshaw, J. L., & Wallace, G. (1971). Interhemispheric effects on reaction time to verbal and nonverbal visual stimuli. Journal of Experimental Psychology, 87, 415-422. Gordon, W. A, Hibbard, M. R, Egelko, 5., Diller, L., Shaver, M. S., Lieberman, A, & Ragnarrson, K. (1985). Perceptual remediation in patients with right brain damage: A comprehensive program. Archives of Physical Medicine and Rehabilitation, 66, 353-359. Heilman, K. M. (1979). Neglect and related disorders. In K. M. Heilman & E. Valenstein (Eds.), Clinical neuropsychology (pp. 268 307). New York: Oxford University Press. Heilman, K. M., Bowers, D., Valenstein, E., & Watson, R T. (1987). In M. Jeannerod (Ed.), Advances in psychology 45: Neurological and neuropsychological aspects of spatial neglect (pp. 115-150). North Holland: Elsevier Science Publishers B.V. Heilman, K. M., & Watson, R 1: (1977). The neglect syndrome-a unilateral defect of the orienting response. In S. Harnard (Ed.), Lateralization in the nervous system (pp. 285-302). New York: Aca

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Kinsbourne, M. (1987). Mechanisms of unilateral neglect. In M. Jeannerod (Ed.), Advances in psychology 45: Neurological and neu ropsychologiC41 aspects of spatial neglect (pp. 69-86). North Holland: Elsevier Science Publishers B. V. Kinsella, G., & Ford, B. (1980). Acute recovery patterns in stroke patients. The Medical Journal of Australia, 2, 663-666. Kinsella, G., & Ford, B. (1985). Hemi-inattention and the recovery patterns of stroke patients. International Rehabilitation Medicine, 7, 102-106. Kotila, M., Niemi, M. L., & Laaksonen, R (1986). Four-year progno sis of stroke patients with visuospatial inattention. Scandinavian Journal of Rehabilitation Medicine, 18,177-179. Lassen, M. A, Ingvar, D. H., & Skinhoj, E. (1978). Brain function and

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tion to visuospatial neglect. In M. Jeannerod (Ed.), Advances in psychology 45: Neurophysiological and neuropsychological aspects of spatial neglect (pp. 215-233). North Holland: Elsevier Science Pub lishers B. V. Ottenbacher, K. J. (1986). Evaluating clinical change. Baltimore, MD: Williams & Wilkins. Pelland, M. (1986). Unilateral neglect: Visual field defect, oculomo tor dysfunction, or body scheme disorder? Sensory Integration Special Interest Section Newsletter, 9(4), 1,5. Risberg, J., Halsey, J. H., Wills, E. L., & Wilson, E. M. (1975). Hemispheric specialization in normal man studied by bilateral measurements of the regional cerebral blood flow: A study with the 133 Xe inhalation technique. Brain, .98, 511-524. Sasanuma, 5., Hoh, M., Mori, K., & Kobayashi, Y. (1977). Tachis toscopic recognition of Kana and Kanji words. Neuropsychologia, 15,547-553.

therapy. Appreciation is extended to the New England Rehabilitation Hospital in Woburn, Mass., the SpaUlding Rehabilitation Hospital in Bos ton, and Braintree Hospital in Braintree, Mass., for their support and assis tance with this research, and to Marcel Kinsbourne, MD, for his thoughtful insights on interpreting the results of this study.

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Acknowledgment This study was supported in part by the American Occupational Therapy Foundation and the American Occupational Therapy Association through their funding of the Neurobehavioral Rehabilitation Research Center at Boston University, a center for scholarship and research in occupational

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