Deficits in temporal sequencing of verbal material: The effect of laterality of lesion

Temporal sequencing of verbal materials (digits, words, and geometric forms) presented in two sensory modalities (auditory and visual) to three groups of subjects (Broca's with left anterior lesions, patients with right hemisphere lesions, and normals) was examined. Each subject was asked to point to a set of stimuli in the same sequence as presented by the examiner. Results indicated that patients with left hemisphere lesions were more impaired on all tasks than the right hemisphere lesioned patients who, in turn, were impaired compared to normal controls. Response to auditory presentation was superior to response to visual presentation. Also, digits were the easiest for all groups, and words were easier than geometric forms. Of special interest was the finding which suggested that right hemisphere lesions are associated with impairment of verbal temporal sequencing under either auditory or visual presentation.     

Bilateral capacity for speech sound processing in auditory comprehension: evidence from Wada procedures

Data from lesion studies suggest that the ability to perceive speech sounds, as measured by auditory comprehension tasks, is supported by temporal lobe systems in both the left and right hemisphere. For example, patients with left temporal lobe damage and auditory comprehension deficits (i.e., Wernicke's aphasics), nonetheless comprehend isolated words better than one would expect if their speech perception system had been largely destroyed (70-80% accuracy). Further, when comprehension fails in such patients their errors are more often semantically-based, than-phonemically based. The question addressed by the present study is whether this ability of the right hemisphere to process speech sounds is a result of plastic reorganization following chronic left hemisphere damage, or whether the ability exists in undamaged language systems. We sought to test these possibilities by studying auditory comprehension in acute left versus right hemisphere deactivation during Wada procedures. A series of 20 patients undergoing clinically indicated Wada procedures were asked to listen to an auditorily presented stimulus word, and then point to its matching picture on a card that contained the target picture, a semantic foil, a phonemic foil, and an unrelated foil. This task was performed under three conditions, baseline, during left carotid injection of sodium amytal, and during right carotid injection of sodium amytal. Overall, left hemisphere injection led to a significantly higher error rate than right hemisphere injection. However, consistent with lesion work, the majority (75%) of these errors were semantic in nature. These findings suggest that auditory comprehension deficits are predominantly semantic in nature, even following acute left hemisphere disruption. This, in turn, supports the hypothesis that the right hemisphere is capable of speech sound processing in the intact brain.     

自我概念一致性与幸福感间的关系：文化的调节作用

自我概念一致性已经被证明对于享乐的和自我实现的幸福感具有促进作用。然而文化可以影响它们之间的关系。西方人崇尚个人主义, 具有独立型自我构念和低水平的辩证思维, 因此他们的自我概念一致性较高, 且对幸福感具有强烈的促进作用。而东方人崇尚集体主义, 具有互依型自我构念和高水平的辩证思维, 因此他们的自我概念一致性较低, 且对幸福感的促进作用微弱。未来的研究需要在特质以外的人格水平上, 检验不同分类标准下的自我概念一致性与文化和多种类型的幸福感间的关系。并且探索文化发挥作用的其他机制, 解析文化与自我概念相互作用, 共同影响幸福感的深层机制。     

Spoken syntax in children with acquired unilateral hemisphere lesions

The spoken syntax of eight left hemisphere lesioned and eight right hemisphere lesioned children were compared to matched controls. The children's lesions were acquired between 0.08 and 6.17 years of age (mean = 1.33 years), and at the time of testing they were between 1.67 and 8.15 years of age (mean = 4.19). Based on analyses of spontaneous language samples, left hemisphere lesioned subjects performed more poorly than did their controls on most measures of simple and complex sentence structure. In contrast right lesioned subjects performed similarly to their controls on these measures, except for a tendency to make more errors in simple sentence structures. These findings provide further evidence that the left and right hemispheres are not comparable in supporting syntactic abilities.     

A Search for the Optimal Stimulus

How do stimulus size and item number relate to the magnitude and direction of error on center estimation and line cancellation tests? How might this relationship inform theories concerning spatial neglect? These questions were addressed by testing twenty patients with right hemisphere lesions, eleven with left hemisphere lesions and eleven normal control subjects on multiple versions of center estimation and line cancellation tests. Patients who made large errors on these tests also demonstrated an optimal or pivotal stimulus value, i.e., a particular size center estimation test or number of lines on cancellation that either minimized error magnitude relative to other size stimuli (optimal) or marked the boundary between normal and abnormal performance (pivotal). Patients with right hemisphere lesions made increasingly greater errors on the center estimation test as stimuli were both larger and smaller than the optimal value, whereas those with left hemisphere lesions made greater errors as stimuli were smaller than a pivotal value. In normal subjects, the direction of errors on center estimation stimuli shifted from the right of true center to the left as stimuli decreased in size (i.e., the crossover effect). Right hemisphere lesions exaggerated this effect, whereas left hemisphere lesions diminished and possibly reversed the direction of crossover. Error direction did not change as a function of stimulus value on cancellation tests. The demonstration of optimal and pivotal stimulus values indicates that performances on center estimation and cancellation tests in neglect are only relative to the stimuli used. In light of other studies, our findings indicate that patients with spatial neglect grossly overestimate the size of small stimuli and underestimate the size of large stimuli, that crossover represents an “apparent” shift in error direction that actually results from normally occurring errors in size perception, and that the left hemisphere is specialized for one aspect of size estimation, whereas the right performs dual roles.     

Perceptual biases in processing facial identity and emotion

Normal observers demonstrate a bias to process the left sides of faces during perceptual judgments about identity or emotion. This effect suggests a right cerebral hemisphere processing bias. To test the role of the right hemisphere and the involvement of configural processing underlying this effect, young and older control observers and patients with right hemisphere damage completed two chimeric faces tasks (emotion judgment and face identity matching) with both upright and inverted faces. For control observers, the emotion judgment task elicited a strong left-sided perceptual bias that was reduced in young controls and eliminated in older controls by face inversion. Right hemisphere damage reversed the bias, suggesting the right hemisphere was dominant for this task, but that the left hemisphere could be flexibly recruited when right hemisphere mechanisms are not available or dominant. In contrast, face identity judgments were associated most clearly with a vertical bias favouring the uppermost stimuli that was eliminated by face inversion and right hemisphere lesions. The results suggest these tasks involve different neurocognitive mechanisms. The role of the right hemisphere and ventral cortical stream involvement with configural processes in face processing is discussed.     

Aspects of self-concept and their relationship to language performance and verbal reasoning ability

It has been claimed that self-concept is multidimensional, with dimensions such as mathematical self-concept and self-concept in language. The present study investigated the relationship of academic self-concept in language with performance on school-related language tasks and verbal reasoning ability. A total of 512 students in grades 7, 9, and 11 rated four aspects of their academic self-concept in language: self-perception, self-efficacy, self-esteem, and others' perception of their abilities. Verbal reasoning ability and performance on language tasks were assessed. Path analysis showed that performance on language tasks was influenced strongly by verbal reasoning abilities. Self-esteem and others' perception of one's abilities were affected directly by language performance. No direct relationship was found between academic self-concept in language and verbal reasoning ability. The results suggest that adolescents do not construe their academic self-concept according to their abilities but according to their performance in school and others' response to it.     

Evidence for differentiation of right hemisphere visual-perceptual functions

Performance on tasks sensitive to right hemisphere dysfunction (facial discrimination and perceptual closure) are reported in eight patients with right hemisphere lesions. Patients demonstrated an apparent double dissociation of performance on the two measures. Site-by-task specificity for the closure task was strongly suggested. Implications for right hemisphere organization and underlying psychological processes are considered.     

Semantic disorders of auditory language comprehension in right brain-damaged patients

A test of auditory language comprehension was given to 110 right brain-damaged patients and to 94 normal controls in order to check if patients with lesions of the right (nondominant) hemisphere make a significantly higher number of semantic errors than normals. Confirmation of the hypothesis was obtained, but the relationship between semantic errors and lesion of the right hemisphere did not seem a simple and direct one. In fact, most of the lexical-semantic errors were due to associated variables (such as unilateral spatial agnosia and general mental deterioration) and not to the lesion of the right hemisphere per se. These data do not suggest a specific semantic capacity of the nondominant hemisphere but rather stress the fragility of the lexical-semantic organization at the cortical level.This work was assisted by a grant from C.N.R. (Consiglio Nazionale delle Ricerche).     

Sex differences in spatial task performance of patients with and without unilateral cerebral lesions

Two visuospatial tasks, the WAIS Block Design and the Street Gestalt Completion Test, were administered to men and women with and without unilateral cerebral lesions. These two tasks represent different categories of visuospatial functions. The Street test is a visual-perceptual gestalt task, requiring the closure of fragmented pictures, whereas Block Design is an analytical, manipulospatial task requiring rotation of spatial coordinates. For the non-brain-damaged group, the men showed a nonsignificant trend toward better Block Design performance relative to the women, whereas there was no sex-related difference in Street performance. For the brain-damaged groups, patients with right hemisphere lesions performed significantly worse than patients with left hemisphere lesions on both the Street test and Block Design, indicating that both tasks were more sensitive to right hemisphere functioning. There was, however, a significant sex X side of lesion interaction on Block Design only, with the men showing a more asymmetrical pattern of scores. These results suggest that sex differences in functional lateralization may underlie sex differences in visuospatial ability, and that sex differences in functional lateralization may be present for only certain visuospatial processes.     

自我概念威胁以及与重要他人的比较共同削弱自我面孔优势效应

内隐积极联想理论(implicit positive association, IPA)认为自我面孔识别以及与之伴随的自我意识激发了自我概念的积极属性, 促进了对自我面孔的识别优势, 因此通过自我概念威胁可以削弱自我面孔识别的优势效应。本研究旨在探讨自我概念威胁以及与重要他人的比较对自我面孔优势效应的共同影响。实验一为自我-朋友对比实验, 10对同性好友(20名被试)在接受完自我概念威胁启动或者非威胁性启动后对自我面孔和朋友面孔进行朝向的判断, 结果发现非威胁性启动后, 自我面孔的优势效应依然存在, 而在自我概念威胁启动后, 自我面孔优势效应消失。实验二为自我-陌生人对比实验, 另外20名被试在接受完自我概念威胁启动或者非威胁性启动后, 对自我面孔和陌生人面孔进行朝向的判断, 结果发现, 无论是自我概念威胁启动还是非威胁性启动后, 自我面孔识别优势效应都依然存在。两个实验的结果均主要体现在用左手进行反应的时候。结果表明：自我概念威胁以及与重要他人的比较共同削弱自我面孔优势效应; 而左手效应的发生似乎表明了大脑右半球对自我面孔识别的主导和调节作用。     

Impairment of auditory perception and language comprehension in dysphasia

Men with chronic focal brain wounds were examined for their ability to discriminate complex tones, synthesized steady-state vowels, and synthesized consonant—vowel syllables. Subjects with left hemisphere damage, but not right hemisphere damage, were impaired in their ability to respond correctly to rapidly changing acoustic stimuli, regardless of whether stimuli were verbal or nonverbal. The degree of impairment in auditory processing correlated highly with the degree of language comprehension impairment. The pattern of impairment of the group with left hemisphere damage on these perceptual tests was similar to that found in children with developmental language disorders.     

Unilateral brain lesions in childhood: performance on the Revised Token Test

Comprehension of connected language as assessed by the Revised Token Test (RTT) was studied in 17 children with left hemisphere lesions (LL) and 11 with right hemisphere lesions (RL). LL children's significantly lower performance on several subtests than left controls (LC) matched by age, sex, race, and social class appeared to be related to the memory demands of these subtests rather than the limited syntactic elements assessed by the RTT. LL subjects requested significantly more command repetitions than control or RL subjects and when a repetition was not requested LL subjects often responded with immediacy. Although RL children tended to perform lower than right matched controls (RC), these differences were not significant nor readily related to either the memory or specific linguistic structures assessed. RL subjects required fewer command repetitions than LL subjects and exhibited a significantly greater frequency of immediate responses than controls or LL subjects. While based on few children, a trend for LL children with retrorolandic lesions to perform more poorly than those with left prerolandic lesions was suggested. No systematic difference in performance was apparent for children with left cortical vs. left subcortical lesions or among discrete sites of lesions within the right hemisphere. Children with left lesions prior to 1 year of age performed no better and, in several instances, significantly poorer than LL patients sustaining lesions after 1 year of age. Among RL subjects, those sustaining lesions after 1 year of age had greater difficulty than those with lesion onset before 1 year of age, especially on linguistic elements which seemed to be dependent upon visual spatial properties. Further studies are needed to evaluate the comprehension of more complex linguistic structures among children with unilateral brain lesions as well as to study the role of more basic factors such as memory and attention in explaining the present findings.     

Recognition of Facial Expression in Diverging Socioeconomic Levels

Cerebral organization has been seen to vary in different social or ethnic groups; also, sociocultural retardation is a serious obstacle to development in poorer countries. The ability of the right hemisphere to recognize facial emotions in a tachistoscopic task was tested in university and low-socioeconomic-level subjects. All were male and right-handed. The university students recognized facial emotions projected to their left field-right hemisphere significantly better than with their right field-left hemisphere; the low-socioeconomic-level subjects showed no differences in hemispheric performance. The explanation of laterality as a function of social class may be of importance in dealing with sociocultural retardation.     

Selective loss of complex-pitch or speech discrimination after unilateral lesion

Twenty-eight right-handed patients who suffered a single cerebrovascular accident in the distribution of either the left or right middle cerebral artery were tested on their ability to discriminate complex-pitch and speech stimuli presented dichotically. Whereas the left hemisphere lesion group was impaired in dichotic speech but not in dichotic complex-pitch discrimination, the right hemisphere lesion group was impaired in dichotic complex pitch but not in dichotic speech discrimination. Complex-pitch phenomena may provide a useful model for the study of auditory function in the nondominant hemisphere.     

Hemihypokinesia after right hemisphere stroke

We tested the hypothesis that the right hemisphere is dominant for motor activation of "intention." If the right hemisphere is dominant for intention and if intention is a prerequisite for movement, motor impairment should be worse after an infarct in the right hemisphere than in the left. We asked nine subjects with right and nine with left hemisphere infarcts to elevate each shoulder independently. Subjects with right hemisphere lesions had more trouble moving the contralateral shoulder. The data are consistent with the hypothesis that the right hemisphere is dominant for motor activation or intention.