Different psychological effects of lateralized brain damage

Laterality of Cognitive Functions in Achieving Hemiplegic Children

7 left and 7 right children with infantile hemiplegia were compared with 7 physically normal children on the Wechsler Intelligence Scale for Children and Reitan-Indiana Neurological Tests. Although the brain-injured children are achieving satisfactorily in school and no differences were found among the three groups on the Wide Range Achievement Test, the left hemiplegics were poorer than the normals in visuo-perceptual performance and the right hemiplegics poorer than the normals in verbal intelligence. The results suggest that even in educationally advanced children, compensation for early, asymmetrical brain damage is not complete. Recommendations were made for early assessment of asymmetrical cognitive abilities and differential instructional procedures.

WISC-R and K-ABC Performances of Hemiplegic Children

Three groups of 12 right hemiplegic, 12 left hemiplegic, and 12 control children 6 to 12 years in age were administered the Wechsler Intelligence Scale for Children-Revised (WISC-R), the Kaufman Assessment Battery for Children (K-ABC), and the Finger Tapping Test (FTT). Children with left hemiplegia performed significantly below control children on both IQ measures. Children with right hemiplegia differed significantly from controls in Performance IQ test performance. Neither test completely reflected lateralized cognitive deficits in the hemiplegic children. Only the left hemiplegic group demonstrated a significant scale score difference with Simultaneous < Sequential. The groups did not differ in the number of children with scale score differences > 15. These findings suggest that congenital hemiplegia in children is not predictive of large intraindividual IQ scale differences, nor does it result in patterns of cognitive deficits found in adults with unilateral brain damage.

Cognitive processing and self-report of lateral preference

Our knowledge of the human brain has increased more during the past 40 years than at any other time in history. Of particular interest have been the findings of a correspondence between cognitive functions and individual structures of the brain. Similar from a gross anatomical point of view, the hemispheres of the brain have been shown to serve specialized cognitive functions. This work offers an overview of the cognitive aspects of cerebral lateralization as a context for considering this issue, followed by a review of specific self-report techniques in the appraisal of lateral preference.

How useful is the WAIS-R in closed head injury assessment?

The present study examined whether head-injury assessment findings based on the WAIS could be generalized to the WAIS-R. It also investigated whether WAIS-R findings from individuals with focal mass lesions could be generalized to closed-head-injured patients with mass lesions. Subjects were 71 CHI patients assessed with the WAIS-R an average of 1.38 years post-injury. Results were not always consistent with previous research. Patients with left or right mass lesion loci did not exhibit previously reported Verbal IQ-Performance IQ discrepancies.

Lateral preference and neuropsychological correlates of schizotypy

A battery of 11 schizotypy questionnaires was administered to 316 male undergraduates. The scores of the 266 white subjects were subjected to a principal components analysis, and 73 subjects scoring at the upper and lower ends of the factor score distribution based on the first unrotated component were recalled for neuropsychological testing. The battery of neuropsychological tests consisted of four tests of motoric performance, four subtests from the Wechsler Adult Intelligence Scale-Revised, the conjugate lateral eye movement test, and a lateral preference questionnaire. Subjects high on schizotypy did not differ from low scorers on overall neuropsychological performance or performance asymmetries. High scorers did show a sinistral shift in hand and foot preference and more crossed dominance compared with controls. Asians scored significantly higher than whites on several schizotypy scales, raising the question of a possible ethnic bias in these measures.

Cognition in eating disorders

Cognitive functions were investigated in four groups of women: 30 underweight anorexics, 38 normal-weight bulimics, 20 long-term weight-restored anorexics, and 39 normal controls. A MANOVA was used to examine performance on five neuropsychological domains derived from prior principal components analyses of a comprehensive neuropsychological battery. Underweight anorexics performed more poorly than normal controls in four of five neuropsychological domains (focusing/execution, verbal, memory, and visuospatial), while normal-weight bulimics showed poorer performances only in focusing/execution. The absolute differences in scores between eating disorder groups and normal controls were for the most part small, suggesting subtle rather than frank cognitive difficulties. Poorer neuropsychological test performance was associated with anxiety but not depression as measured by the Tryon, Stein, and Chu Tension scale and scale 2 of the MMPI respectively. The findings support previous reports of attentional difficulties in eating disorders but do not support the hypothesis of differential right-hemisphere dysfunction in eating disorders.

Neuropsychological assessment of brain damage: discriminative validity of the McCarron-Dial System

The purpose of this study was to investigate the discriminative validity of the McCarron-Dial System (MDS) in neuropsychological assessment. Multiple discriminant analysis results indicate that 92.6% of the brain-damaged and non-brain-damaged groups, and 69.6% of the right, left and diffused brain-damaged subgroups were correctly classified using the abbreviated version of the MDS. The results tentatively support the discriminative ability of the MDS for neurobehavioural diagnosis. Since the MDS has a long tradition in vocational rehabilitation and established strengths in predicting vocational and community adjustment outcomes, it may be potentially useful for both vocational and clinical neuropsychological assessment.

IQ patterns in affective disorder, lateralized and diffuse brain damage

Meta-analysis of 38 studies compared Wechsler IQ scores in affective disorder (A), lateralized right (RH), left (LH) and bilateral/diffuse (BI) brain damage. A, RH, and BI had lower PIQ than VIQ. In A and BI groups the PIQ/VIQ ratio was identical, whereas each differed significantly from the RH group which revealed a much lower PIQ/VIQ ratio. Similarity of neuropsychological profiles of A and RH patients is often interpreted as indicating predominant right-hemisphere involvement in affective disorder. The present findings suggest an alternative interpretation is possible: i.e., the presence of bilateral/diffuse CNS involvement in affective disorder. We do not believe that our findings strongly support one interpretation over the other. In future research, both possibilities should be considered.

Another look at VIQ-PIQ scores and unilateral brain damage

The relationship of WAIS, VIQ, PIQ and Aphasia Screening scores to unilateral brain damage was investigated using 18 subjects with left hemisphere damage (LHD) and 19 subjects with right hemisphere damage (RHD). Expected VIQ-PIQ difference scores were demonstrated only for the RHD subjects. Aphasia was significantly associated with PIQ in the LHD group. ANCOVAR using Aphasia Screening as a covariate produced significant LHD versus RHD differences on PIQ. These data question the utility of VIQ-PIQ difference scores in the diagnosis of unilateral brain damage. Second, the data suggest that LHD "non-verbal" deficits are the result of underlying language disturbance and not the consequence of impaired visuoperceptive or visuospatial processes.

Language and visuospatial abilities in learning-disabled, brain-damaged, and nondisabled young adults

This study confirmed the construct validity of dysphasic errors but not of Block Design or dyscopia for 88 male and 22 female young adults, aged 17 to 29 yr. Right-hand sensorimotor deficits correlated with dysphasic errors but not with Block Design. Brain-damaged and learning-disabled with Halstead Impairment Index (HII) greater than or equal to 0.4 differed from nondisabled on both dysphasic errors and Block Design. Learning-disabled with HII less than 0.4 differed from nondisabled only for dysphasic errors. As a group, young learning-disabled adults had impaired language abilities. Learning-disabled with HII greater than or equal to 0.4 and brain-damaged had generalized neuropsychological deficits characterized by less adequate language and visuospatial abilities.

Dichotic listening tests in studying brain-behavior relationships

The magnitude of perceptual asymmetry (PA) on a CVC fused dichotic words test and on VCV and CV fused nonsense syllables tests were compared. In each test the set of distinguishing phonemic cues was the same; the six English stop consonants, b,p,d,t,g,k. Although test-retest reliability was very high on all three tests there was no correlation across individuals between the degrees of PA on different tests. Moreover, the magnitude of PA on the VCV nonsense test increased as field dependence (FD) increased on the field dependence index (FDI) of the WAIS while there was no relationship between FD and the magnitude of PA on the CVC words test. In addition, concurrent visual tasks increased PA on the VCV nonsense test and decreased it on the words test. In order to facilitate the use of such data, Kimura's classical model of the physiological basis of PA is modified by including components of primary receptive and secondary and tertiary associative function. Comparison of highly similar PA measures, that differ in specific ways, is discussed as a means of collecting data for mapping cerebral functional space and exploring brain-behavior relationships.

Cognitive profile of children referred to a clinic for reading disabilities

Cognitive performance asymmetries in favor of functions attributed to the right cerebral hemisphere are reported for 105 out of 108 subjects referred to a clinic for reading difficulties. Children were referred by their parents, teachers, psychologists or doctors for diagnosis and treatment of reading difficulties in school. Virtually all subjects who were behind in reading—not explained by intelligence or opportunity factors—performed, on the average, better than the norm by about 0.50 S.D. on tests usually attributed to the right cerebral hemisphere and poorer than the norm by the same amount on tests attributed to the left cerebral hemisphere. The sample had four times as many males as females and reading retardation in females was only slightly greater Both overall performance as well as degree of asymmetry increased with parent education.

These results suggest that reading disabled children are homogeneous with at least the right/left asymmetry aspect of their cognitive profile. The consistent asymmetry further suggests that the concept of cognitive laterality, as well as the test instrument used here to measure it, may be of diagnostic value and be useful in the establishment of risk factors in a nonidentified population

Wechsler VIQ versus PIQ differences in cerebral dysfunction: a literature review with emphasis on sex differences

For the past three decades neuropsychologists have published results which indicated that left-sided cerebral dysfunction affected the Wechsler Verbal Scale whereas right-sided dysfunction affected the Performance Scale. Recent investigations have indicated that the effects of cerebral dysfunction on performance of the Wechsler Scales may be different for males and females. In view of these reports, the present review considered 24 studies (28 samples) which have reported Wechsler IQ scores in patients with unilateral or bilateral cerebral dysfunction. Eight studies (10 samples) used the Wechsler-Bellevue I, whereas 16 studies (18 samples) employed the WAIS. In these 28 published samples, there were four exceptions to the hypothesis of lower mean VIQ in patients with left-hemisphere lesions, and lower mean PIQ in patients with right-hemisphere dysfunction. Of the four exceptions to this "rule", two samples contained only women, while a third contained only patients with missile wounds of the frontal lobe. One sample appeared to be a true exception, and could not be accounted for by lesion location or sexual composition of the sample. The studies reviewed appear to add additional support to the hypothesis of sex differences in the effects of unilateral lesions. Therefore, insofar as published mean values for the Wechsler Scales are concerned, the specific effects on Verbal versus Performance IQ appear more prominently in males.

Hemispheric asymmetries and early infantile autism

The observation that language disorders constitute a major symptom of early infantile autism has led some researchers to speculate that the autistic syndrome may be a result of brain damage to the left hemisphere. Such speculation has fostered a number of studies in which attempts have been made to link autism with ostensibly positive signs of left hemisphere damage, such as left-handedness and preferences for "right hemisphere" functional and cognitive activities. In the present review, contributions to this area are systematically reviewed. Studies attempting to demonstrate that an unusually high incidence of left-handedness occurs in autistic samples are examined. Functional and morphological studies examining patterns of asymmetry in autistic samples are reviewed. It is shown that most studies on handedness fail to account adequately for the role that age of subjects may play in the manifestation of left-handedness. A simple cause-and-effect model of abnormal cerebral asymmetry and autism is rejected in favor of a more integrative yet parsimonious model that specifically attempts to explain the language disorder common to autism.

Differing lateralized perceptual-motor patterns in schizophrenic and non-psychotic children

A neuropsychological assessment stressing lateralized perceptual-motor and cognitive abilities was administered to two groups of hospitalized child and adolescent psychiatric patients, 25 schizophrenics and 25 non-psychotics. The findings included an increased incidence of crossed eye-hand dominance in schizophrenics, poorer tactile sensory function in the right hands of schizophrenics than in the left hands, and lower Vocabulary and Similarities WISC subtest scores than Block Design and Object Assembly scores for schizophrenics. Right-left confusion was associated with finger agnosia for schizophrenics. The results supported the hypothesis that there may be left-hemisphere dysfunction in schizophrenia; however, no single pattern of dysfunction was apparent.

Lateralized psychological impairment associated with CT lesions in head injured patients

Twenty-six adult patients with CT scans were given the Wechsler Adult Intelligence Scale (WAIS) during recovery from an acute head injury. Focal lesions were observed on the initial CT scans of 24 patients. These included 13 in the right hemisphere, 8 in the left hemisphere and 3 in both hemispheres. Diffuse cerebral swelling was observed in the remaining 2 patients. Both the standard WAIS examination (11 subtests) and a shorter version described by McFie (7 subtests) were used to assess psychological impairment associated with CT documented lesions. The McFie method involved a special scoring procedure that utilized reference subtests as an index of premorbid functioning. When mean algebraic differences between Verbal and Performance subtests were used, both methods differentiated left and right-sided lesions to a highly significant degree (p less than .001). Lateralized lesions yielded significant differences on 3 individual subtests (1 Verbal and 2 Performance) with the McFie method and on 6 individual subtests (all Verbal) with the standard WAIS procedure. Wechsler's Deterioration Quotient did not discriminate between groups. It was concluded that the traditional distinction between Verbal and Performance subtests on the WAIS was valid for CT documented lesions, and the shorter McFie version was as effective as the standard WAIS in lateralizing psychological dysfunction. Acknowledgements. This research was supported by Contract NS 5-2316 and Grant NS 08803 from the National Institutes of Health. We are grateful to Drs. Thomas A. Gennarelli and Howard I. Hurtig for patient referrals and neurological evaluations.

Three patterns of brain damage of the WAIS

Compared four groups of matched Ss (40 each) in order to examine different subtest patterns of brain damage on the WAIS, using F-tests and age mean profiles. The groups were: Normals, diffuse cortical degeneration, right and left hemisphere damage. The results indicated three patterns: (1) a normal pattern; (2) a diffuse degenerative and right hemisphere pattern; and (3) a left hemisphere pattern. The diffuse degenerative results were not significantly different from the right hemisphere results. The left hemisphere pattern had no large verbal vs. performance differences. These patterns appear to be produced by the interaction of three brain damage effects: (1) a general effect; (2) a right hemisphere effect; and (3) a left hemisphere effect. Verbal tests are both "hold" and left hemisphere tests, while three Performance Tests are "don't hold" and right hemisphere tests. The WAIS requires other specific tests of brain damage for an adequate assessment of brain damage.

Patterns of cognitive impairment in children with suspected and documented neurological dysfunction

WISC Verbal-Performance discrepancy, Vocabulary-Block Design discrepancy, and Similarities-Object Assembly discrepancy were investigated in matched samples of 25 normal, suspected neurological dysfunction, and documented neurological dysfunction children. The results suggest a continuum of deficit in these samples ranging from normal performance by normal controls to moderate impairment in Ss with documented neurological dysfunction. The suspected neurological dysfunction sample occupied a median position in the continuum as predicted. An analysis of WISC IQ and subtest scores in the three samples also supported the predicted continuum of deficit. Specific WISC subtest comparisons may be of some research and clinical utility in the prediction of neurological dysfunction in pediatric patients.

Cognitive effects of unilateral brain lesions secondary to penetrating missile wounds

The WAIS verbal and nonverbal subtest performance of Ss with unilateral brain lesions secondary to penetrating missile wounds was examined and compared with that of normal controls. The performance of matched right- and left-hemisphere lesion Ss differed significantly on only two verbal and one nonverbal measures, however, all performance differences were in the direction hypothesized. The performance of right-hemisphere lesioned and control Ss differed significantly on all measures, with consistently lower scores by brain-injured Ss, while the performance of left-hemisphere and control Ss differed significantly on the three verbal measures and WAIS Full Scale IQ. These results are in general agreement with previous reports using a similar research design and tend to support the hypothesis of differential impairment of verbal and nonverbal test performance in Ss with unilateral brain lesions.

Verbal problem solving as related to cerebral damage

An instrument, called the Word Finding Test, was devised to evaluate ability in discerning the meaning of a nonsense word through appreciation of its verbal context. This test consisted of 20 items and each item was made up of five sentences. In each sentence a nonsense word was used in place of an actual word which fit the context of all sentences for that item. S's task was to guess the meaning of the nonsense word, if possible, in each item. The test was administered to groups (males and females) of control Ss as well as to a group of normally functioning control Ss. Ss with cerebral lesions, who had also taken the test, were matched individually with Ss in each of the control groups on the basis of age, sex, and education. The results indicated that groups with cerebral damage consistently performed worse than their matched control groups. In total, 66 (94%) of the 70 brain-damaged Ss earned lower scores than did their matched controls. These findings indicated that the Word Finding Test appears to be especially sensitive to cerebral damage in adult Ss and suggest that problem-solving abilities, even in a verbal context, may be seriously deficient in persons with cerebral lesions.

Halstead's Category Test and lateralized brain damage

Left-hemisphere-damaged (with Verbal IQ deficits) and right-hemisphere-damaged (with Performance IQ deficits) male, adult patients were compared on Halstead Category Test Performance. Deficits of approximately the same magnitude were found. These results and other evidence question the importance of language mediation on nonverbal, visual-spatial abstracting tests.

Lateralized brain damage and differential psychological effects: Parsons, et al., re-examined

Parsons, et al. stated that left-hemisphere damage was associated with a Block Design score significantly higher than the Vocabulary score while the converse was true when the right hemisphere was damaged. Parsons, et al.'s use of age-corrected scaled scores to compensate for chronological age differences among Ss seriously compromised findings since age-corrected scores, so used, cause the criteria of measurement to vary from S to S. Re-analysis of published data, with averaged standard scaled scores substituted, failed to confirm reported findings. A further analysis, based on 21 right-hemisphere-damaged and 15 left-hemisphere-damaged head-injured veterans selected on the basis of equivalent chronological ages, similarly failed to confirm reported differences.

Location of injury and Wechsler indices of mental deterioration

Application of four Wechsler indices of mental deterioration to 95 cases of known head-injured Ss indicates that there are between index differences but that except for the Wechsler Revised index, locus of injury does not affect the efficiency of the indices. The findings were explained on the basis that trauma to the head results in two broad and measurable psychological effects: (1) generalized impairment of concentration and attention and (2), depending upon locus of injury, additional impairments of selective coping skills. In this study, a mixed parietal injury appears associated with deficient conceptualization skills either verbal or motor.

Relation of extent of temporal removals to closure and visuomotor factors

Factor analysis of scores for 159 Ss on the Wechsler-Bellevue Scale of Intelligence, Mooney's Closure Faces test, and a visuomotor task (in which 4 blocks were assembled 10 times alternately into square and triangular frames) yielded 3 similar factors for each sex: Verbal Comprehension, Visual Construction and Closure. Mean factor score estimates showed the expected verbal deficit in 7 patients with left temporal removals and closure deficit in 14 patients with right temporal removals, but no asymmetry for the visuomotor factor. The negative correlation of the latter scores with extent of surgery in the right temporal area was different from the positive one found for the left temporal group.