Facial affect recognition in children: a comparison of the performance of children with right and left hemisphere lesions

This study tests the hypothesis that the right hemisphere is specialized for the processing of emotional information in children, as it is in adults. We compared the performance of eight children with right-hemisphere lesions and eight with left-hemisphere lesions on a test of facial affect recognition. The mean score of the right-hemisphere group fell significantly below that of the left-hemisphere group and normal controls, suggesting that the specialization of the right hemisphere occurs early in development. This finding is consistent with clinical observations that children with right-hemisphere dysfunction manifest a high incidence of difficulty in social interactions.     

Dichotic Listening in Children With Focal Epilepsy: Effects of Structural Brain Abnormality and Seizure Characteristics

The study examined performance on a dichotic listening test in children with focal epilepsy. The aim of the study was to explore how factors related to brain pathology would affect ear advantage. The effects of lateralization of epileptogenic area, size and localization of structural abnormality on MRI findings, and seizure characteristics were studied. Children treated for focal epileptic seizures took part in the study (N = 35). The dichotic test consisted of pairs of words, nonwords, syllables and vowels. Results demonstrated that large congenital structural abnormality in the left hemisphere altered ear advantage whereas smaller abnormality and right-hemisphere abnormality did not. Further, epileptic seizures of left-hemisphere origin that had started at an early age affected ear advantage whereas seizure frequency at the time of the assessment did not. Children with early onset of seizures of right-hemisphere origin had a strong right-ear advantage. The total score did not differ between the groups. There was a strong negative correlation between the scores for the right-ear and the left-ear. The findings were interpreted to indicate altered functional dominance for perception of auditory, lingustic stimuli following early left-hemisphere pathology rather than unilateral functional suppression.     

Dichotic listening in children with focal epilepsy: effects of structural brain abnormality and seizure characteristics

The study examined performance on a dichotic listening test in children with focal epilepsy. The aim of the study was to explore how factors related to brain pathology would affect ear advantage. The effects of lateralization of epileptogenic area, size and localization of structural abnormality on MRI findings, and seizure characteristics were studied. Children treated for focal epileptic seizures took part in the study (N = 35). The dichotic test consisted of pairs of words, nonwords, syllables and vowels. Results demonstrated that large congenital structural abnormality in the left hemisphere altered ear advantage whereas smaller abnormality and right-hemisphere abnormality did not. Further, epileptic seizures of left-hemisphere origin that had started at an early age affected ear advantage whereas seizure frequency at the time of the assessment did not. Children with early onset of seizures of right-hemisphere origin had a strong right-ear advantage. The total score did not differ between the groups. There was a strong negative correlation between the scores for the right-ear and the left-ear. The findings were interpreted to indicate altered functional dominance for perception of auditory, linguistic stimuli following early left-hemisphere pathology rather than unilateral functional suppression.     

Early cognitive and communication development in children with focal brain lesions

Early cognitive and language development of children with congenital focal brain lesions, documented by magnetic resonance imaging, was studied in 18 cases, 9 with left-hemisphere damage and 9 with right-hemisphere damage, at about 2 (Time 1) and 4 years of age (Time 2). All of the children showed normal cognitive development, but their global Griffiths Developmental Scales scores were lower at Time 2, and developmental profiles across individual subscales revealed side-specific effects, resembling the adult left/right cerebral hemisphere lesion model. Expressive lexicon and grammar were delayed, more often in left-hemisphere-damaged than in right-hemisphere-damaged children, at Time 1 and Time 2. Functional findings were not related to the size and location of the brain lesion, whereas the presence of epilepsy was a highly significant predictor of cognitive and language outcome, irrespective of the side of the lesion. The stable disadvantage in the verbal domain shown by left-hemisphere-damaged children within the age range of this study might suggest that the left hemisphere has some initial bias for language learning. The effects of right-hemisphere damage were more variable and emerged at a later stage of language development.     

Differential effects of congenital versus acquired unilateral brain injury on dichotic listening performance: evidence for sparing and asymmetric crowding.

We assessed dichotic speech and complex-pitch discrimination in nine young patients with unilateral left-hemisphere injury and eight young patients with unilateral right-hemisphere injury incurred in the pre-perinatal (congenital) period. As in adults with acquired unilateral lesions, both congenital lesion groups demonstrated poor performance on stimuli presented to the ear contralateral to the lesion. In overall performance on speech discrimination, however, the left-hemisphere congenital lesion group performed significantly better than the acquired-lesion group did. On complex-pitch discrimination, the right-hemisphere congenital lesion group performed significantly better than did the acquired-lesion group, but both left- and right-hemisphere congenital lesion groups were significantly worse at complex-pitch discrimination than were their age- and gender-matched normal controls. These results indicate that although congenital damage produces a "lesion effect" in dichotic listening similar to that after damage acquired in adulthood, overall function is relatively spared. To the extent that complex-pitch discrimination is affected by congenital damage to either hemisphere but speech discrimination is not, the present results are consistent with an asymmetric form of crowding during reorganization after congenital unilateral brain damage.     

Mania after brain injury. A controlled study of causative factors

Eleven patients who developed manic syndromes after brain injury (secondary mania) were studied. Six patients had depressive episodes before mania and five had a definite or possible family history of affective disorder. Eight had lesions involving limbic areas, and nine had right hemisphere involvement. In addition to focal brain injury, mean values for bifrontal and third ventricle/brain ratios of manic patients were significantly increased when compared with non-manic patients who had lesions matched for cause, location, volume, and time since injury. Results indicate that the confluence of either anterior subcortical atrophy and a focal lesion of a limbic or limbic-connected region of the right hemisphere, or genetic loading and a limbic-connected right hemisphere lesion may account for the rare occurrence and specific factors necessary to produce secondary mania.     

Atypical language representation in patients with chronic seizure disorder and achievement deficits with magnetoencephalography

PURPOSE: To characterize the relation between hemispheric asymmetries in language-specific brain activity and reading/spelling achievement by using magnetoencephalography (MEG). METHODS: Patients (n = 83) with medically intractable complex partial seizures of either left- or right-hemisphere origin were classified as having reading and/or spelling deficits (RS) or as not impaired (NI) by using standard achievement tests. All patients had undergone noninvasive functional mapping of receptive language cortex by using MEG as part of a preoperative seizure surgery evaluation. RESULTS: RS patients with left-hemisphere seizure onset exhibited relatively greater activation and earlier onset of late, language-specific MEG activity in posterior temporal and inferior parietal areas of the right as compared with the left hemisphere than did NI patients. These findings also were evident on an individual basis and were independent of global intellectual abilities. CONCLUSIONS: Reading and spelling achievement deficits in patients with complex partial seizures of left-hemisphere origin are associated with atypical language organization, possibly secondary to reorganization of language function to right-hemisphere areas that are not as efficient as homotopic areas in the left hemisphere in supporting reading and spelling functions.     

Long-term effects of focal, cortical injuries upon articulation and discrimination performance

Residual, long-term effects of cortical injuries upon speech production are rarely examined. In this study, we examined the articulation and discrimination abilities in twelve subjects who received focal, cortical injuries in Vietnam during 1968-1971. The subjects were divided into two groups based upon the hemisphere (right or left) of lesion. Data revealed the left-hemisphere injured group produced a greater number of articulation and discrimination errors than the right-hemisphere injured group. Articulation errors occurred more often than discrimination errors in both groups. However, a feature analysis revealed the left-hemisphere injured group made predominantly combination errors and the right-hemisphere injured group made predominantly place errors. Taken overall, the data suggest the left-hemisphere injured group may experience residual difficulties with the encoding of phonological units while the right-hemisphere injured group appears to have residual problems that may be related to the spatial correlates of speech.     

Memory functions in aphasic and non-aphasic stroke patients

Abstract

We studied selected memory functions in 15 left-hemisphere stroke patients with aphasia, five non-aphasic left-hemisphere stroke patients, 16 right-hemisphere stroke patients and 10 normal controls. Memory was tested systematically for immediate recall of digits and letters, short-term (15 s) recognition of auditory and visual words and of non-verbal designs, and long-term (15 s) recognition of auditory and visual words. CT scan lesion localizations were recorded for all stroke patients. The aphasic group was deficient on immediate and short-term auditory and visual verbal memory tasks, while the right hemisphere group was inferior on both visual non-verbal patterns. Of non-aphasic left-hemisphere stroke patients, only a single patient with a left temporo-occipital lesion showed immediate and short-term verbal memory deficits. Right and left hemisphere aphasic stroke patients with isolated subcortical lesions demonstrated memory impairment, though to a lesser extent than patients with cortical lesions. All groups of stroke patients were deficient on long-term auditory and visual verbal memory. The results are discussed in terms of cerebral localization of memory functions and of the relationships of aphasia to memory dysfunction.     

Utility of the Seashore Tonal Memory Test in neuropsychological assessment

This study assessed the diagnostic utility of the Seashore Tonal Memory Test in detecting and localizing cerebral lesions. A group of 238 subjects with focal or diffuse cerebral lesions and a group of 112 normal comparison subjects were administered the Seashore Tonal Memory Test and the Halstead-Reitan Battery. All brain-damaged subgroups did significantly worse than the normal group on the Tonal Memory Test. Patients with right-hemisphere lesions were more impaired on this test than were those with left-hemisphere lesions. In contrast, Seashore Rhythm Test scores were not significantly different for groups with right- versus left-hemisphere lesions. Tonal Memory performance was not found to be related to more precise location of structural lesions within the right hemisphere. Step-wise discriminate function analyses indicated that the Tonal Memory Test adds to the Halstead-Reitan Battery in discriminating left-hemisphere from right-hemisphere lesions and that, for this purpose, it was a better discriminator than all but one of the individual tests currently in the battery.     

Serum S-100B protein levels in left- and right-hemisphere strokes.

S-100B is a calcium-binding protein that is expressed in astrocytes. We compared the kinetics of serum S-100B in left- and right-hemisphere strokes. Data from 38 acute ischaemic stroke patients who had serial serum S-100B measurements during the first 8 days were analyzed. Stroke severity at baseline, as assessed by the National Institutes of Health Stroke Scale (NIHSS), was similar in the two groups. Mean S-100B values were greater in the right-hemisphere stroke group at all time points. Maximum S-100B levels were low in all patients with lower baseline NIHSS scores, and began to rise at a baseline NIHSS score of 16 for right-hemisphere stroke and 20 for left-hemisphere stroke. S-100B levels were significantly correlated with language in left-hemisphere stroke and with neglect in right-hemisphere stroke. These results are consistent with previous clinical/radiological findings, suggesting that serum S-100B is brain-specific and reflects the extent of brain injury in acute ischaemic stroke.     

Plasticity and reorganization during language development in children with early brain injury

Although some studies have reported subtle language deficits following early focal brain lesions (EFBL), most studies find no evidence for differential language outcomes as a function of lesion side or lesion type in children with congenital injuries to one side of the brain. However, recent prospective studies of the first stages of language development in English-speaking children with EFBL have reported greater delays in expressive vocabulary in children with left-hemisphere damage, particularly if the lesion involves left temporal cortex. In the present study, first stages in the development of word production were studied in 43 Italian children with congenital EFBL, between 13 and 46 months of age. As a group, the EFBL children were markedly delayed in expressive vocabulary. Among children who were in the first stage of language learning, delays were significantly greater with left-hemisphere injury. However, this left-right difference was not evident in children who had moved on to the next stage of language development, producing at least some sentences. Discussion centers on the role of developmental plasticity in determining the outcomes of early focal brain injury, suggesting that recovery from initial delays may take place in the early stages of language development, at least for some children.     

Minor depression after stroke: an initial validation of the DSM-IV construct.

Using 141 patients with a single left- or right-hemisphere stroke, the authors investigated the distinction between major and minor depression after stroke. Major- and minor-depression patients and nondepressed control patients were compared, and a logistic-regression model suggested that major and minor depressions may be cross-sectionally distinguishable disorders. Minor depression was associated with younger age, left-hemisphere lesion location, and more caudal hemisphere lesions. There was an association between minor depression and pathoanatomical variables, with results generally consistent with the categorical vs. the continuum hypothesis of mood disorders in stroke victims. Authors discuss the significance of damage in left-hemisphere posterior portions of the brain for the development of minor depression after stroke.     

Cerebral lateralization of language in normal left-handed people studied by functional MRI

OBJECTIVE: To use functional MRI (fMRI) to further define the occurrence of left-hemisphere, bilateral, and right-hemisphere language in a normal left-handed population. METHODS: A total of 100 healthy volunteers, consisting of 50 left-handed subjects and a reference group of 50 right-handed subjects, were studied by fMRI of the frontal cortex during silent word generation. RESULTS: Ninety-six percent of right-handed subjects showed fMRI changes lateralized to the left hemisphere, whereas 4% showed a bilateral activation pattern. In contrast, left-hemisphere lateralization occurred in 76% of left-handers, bilateral activation in 14%, and right-hemisphere lateralization in the remaining 10%. The predominance of right-hemisphere activation, however, was weak in these cases; only a single left-handed subject (2%) showed complete right-hemisphere lateralization. CONCLUSIONS: Silent word generation lateralizes to the left cerebral hemisphere in both handedness groups, but right-hemisphere participation is frequent in normal left-handed subjects. Exclusive right-hemisphere activation rarely occurred in the frontal lobe region studied.     

Language and verbal memory after right hemispheric stroke: a clinical-CT scan study.

The performances on language and verbal memory tests of 26 right-hemisphere damaged subjects (RHD) have been compared with normal controls and 11 non-aphasic left-hemisphere damaged subjects. While phonological and syntactic performance was unimpaired, a small subgroup of RHD patients, with CT scan evidence of subcortical lesion, was mildly impaired in naming tasks. The performance of RHD patients on free recall was characterized by a reduced recency effect. The implications of these findings for theories about the participation of the right hemisphere in linguistic functions are discussed.     

Neuropsychological dimensions of autism in children: A test of the hemispheric dysfunction hypothesis

Abstract

A neuropsychological study of 10 high functioning autistic children was carried out using a test battery that included tasks purporting to require either left-hemisphere or right-hemisphere strategies and abilities. When compared with mental-aged and-chronological-aged matched control children, the autistic group was found to be significantly poorer on the “left-hemisphere” tests, but to be performing at chronological age level on the “right-hemisphere” tests. Quantitative and qualitative analyses of performance suggested that autistic children are handicapped on tasks that require left-hemisphere mediated approaches and that there is evidence for impairment in performances which are traditionally considered to reflect frontal lobe involvement.     

Lateralized brain dysfunction in schizophrenia: a comparison with patients with lateralized structural lesions

A comparison was made among participants with schizophrenia and those with structural lateralized or diffuse brain damage in order to determine the extent to which the cognitive profile of the schizophrenia sample resembled the profiles obtained from patients with left-hemisphere, right-hemisphere, and diffuse brain damage. The Halstead–Reitan Neuropsychological Battery was used as the testing procedure. The data were subjected to discriminant analysis in order to obtain frequencies of predicted classification of the participants with schizophrenia into schizophrenia, left-hemisphere, right-hemisphere, and diffuse groups. Half of the participants with schizophrenia were classified into the schizophrenia group. The other half was evenly distributed across the left-hemisphere, right-hemisphere, and diffuse brain damage groups. There was not a disproportionately large number of participants classified into the left-hemisphere group. Comparisons among these four predicted groups were accomplished for each of the Halstead–Reitan Battery measures using one-way analysis of variance. The comparison of the subtest scores among the predicted groups indicated that the patients classified into the left-hemisphere group were characterized by a pattern of language dysfunction thought to be developmental in nature, and an abnormal lack of asymmetry in tapping speed favoring the right hand.     

Hemispheric asymmetries and individual differences in visual concept learning as measured by functional MRI

Dynamic changes in brain regions active while learning novel visual concepts were examined in humans using functional magnetic resonance imaging. Participants learned to distinguish between exemplars of two categories, formed as distortions of different unseen prototype stimuli. Regions of the right hemisphere (dorsolateral prefrontal and inferior parietal areas) were active early in learning and throughout task performance, whereas homologous portions of the left hemisphere were active only in later stages of learning. Left dorsolateral prefrontal activation was found only in participants who showed superior conceptual learning. Such a progression from initial right-hemisphere processing of specific instances to bilateral activity as left-hemisphere conceptual processes are recruited may underlie the development of many forms of visual knowledge.     

Sex differences in functional brain asymmetry

Adult male right-handers showed the expected pattern of verbal intellectual decline following left-hemisphere lesions, and depressed nonverbal intelligence following right-hemisphere lesions. In contrast, right-handed women did not show selective verbal or performance intellectual deficits after unilateral brain injury. These findings suggest a greater degree of functional brain asymmetry in right-handed men than women.     

PET imaging of cortical S2 serotonin receptors after stroke: lateralized changes and relationship to depression

Patients with right-hemisphere strokes (N = 9) more than 1 year after injury had greater cortical binding of (3-N-[11C]methyl)spiperone than a similar group of patients with left-hemisphere strokes (N = 8) or normal control subjects (N = 17). The higher S2 serotonin receptor binding occurred in uninjured regions of the right parietal and temporal cortex. The ratio of binding in the ipsilateral to contralateral cortex showed a significant negative correlation with severity of depression scores in the left temporal cortex. These findings suggest that the biochemical response of the brain may be different depending on which hemisphere is injured and that some depressions may be a consequence of the failure to upregulate serotonin receptors after stroke.