The development of spatial and class relations in four young children with right-cerebral-hemisphere damage: Evidence for an early spatial constructive deficit

This study followed the development of four children with right-hemisphere injury on a series of manipulative classification tasks to determine whether and how early brain injury affects the development of spatial and class relations. The children were first tested at about 2 years of age. Their data were compared with previously collected data from 18- to 42-month-old normal children, and with data from four young children with left-hemisphere injury. The results showed the children with right-hemisphere injury do not generate a particular spatial relation (next to) in their spatial groupings with the same frequency as normal or left-hemisphere damaged children, although they do generate in and on relations with normal frequency. An apparent deficit in the development of class relations is shown to be secondary to the spatial deficit, in that it is evident only in tasks that require spatial grouping.     

Early lexical development in children with focal brain injury

Early lexical development in 27 children with focal brain injury was studied cross-sectionally and longitudinally. Data were obtained from children between 12 and 35 months of age who acquired their lesion prenatally or within the first 6 months of life. Results for the group as a whole provide clear evidence for delays in lexical comprehension and production, and for a larger number of comprehension/production dissociations than would be expected by chance. In addition, a significant number of children were observed having unusual difficulty mastering predication and/or using an atypically high proportion of closed class words (suggesting reliance on holistic/formulaic speech). Analyses by lesion type revealed no effect of lesion size. Analyses according to side of lesion revealed that children with right-hemisphere damage produced a higher proportion of closed class words, suggesting heavy reliance on well-practiced but under-analyzed speech formulae. Children with left-hemisphere damage were slightly better in comprehension than children with right-hemisphere damage. In addition, left posterior lesions were associated with greater delays in expressive language, and delays were more protracted in children with left posterior damage. No differential effects of left posterior damage were found for lexical comprehension.     

Differential effects of unilateral lesions on language production in children and adults.

We present the first direct comparison of language production in brain-injured children and adults, using age-corrected z scores for multiple lexical and grammatical measures. Spontaneous speech samples were elicited in a structured biographical interview from 38 children (5-8 years of age), 24 with congenital left-hemisphere damage (LHD) and 14 with congenital right-hemisphere damage (RHD), compared with 38 age- and gender-matched controls, 21 adults with unilateral injuries (14 LHD and 7 RHD), and 12 adult controls. Adults with LHD showed severe and contrasting profiles of impairment across all measures (including classic differences between fluent and nonfluent aphasia). Adults with RHD (and three nonaphasic adults with LHD) showed fluent but disinhibited and sometimes empty speech. None of these qualitative or quantitative deviations were observed in children with unilateral brain injury, who were in the normal range for their age on all measures. There were no significant differences between children with LHD and RHD on any measure. When LHD children were compared directly with LHD adults using age-corrected z scores, the children scored far better than their adult counterparts on structural measures. These results provide the first systematic confirmation of differential free-speech outcomes in children and adults and offer strong evidence for neural and behavioral plasticity following early brain damage.     

Cerebral asymmetry in the perception of American sign language.

American Sign Language (ASL) offers a valuable opportunity for the study of cerebral asymmetries, since it incorporates both language structure and complex spatial relations: processing the former has generally been considered a left-hemisphere function, the latter, a right-hemisphere one. To study such asymmetries, congenitally deaf, native ASL users and normally-hearing English speakers unfamiliar with ASL were asked to identify four kinds of stimuli: signs from ASL, handshapes never used in ASL, Arabic digits, and random geometric forms. Stimuli were presented tachistoscopically to a visual hemifield and subjects manually responded as rapidly as possible to specified targets. Both deaf and hearing subjects showed left-visual-field (hence, presumably right-hemisphere) advantages to the signs and to the non-ASL hands. The hearing subjects, further, showed a left-hemisphere advantage to the Arabic numbers, while the deaf subjects showed no reliable visual-field differences to this material. We infer that the spatial processing required of the signs predominated over their language processing in determining the cerebral asymmetry of the deaf for these stimuli.     

Effects of left-hand preference on postinjury measures of distal motor ability

The relationship of preinjury left-hand dominance for motor performance to postinjury distal motor skills following penetrating brain wounds in patients without overt hemiplegia was examined. We studied 13 controls, 13 right-hemisphere brain-damaged patients, and 11 left-hemisphere brain-damaged patients on motor tasks measuring reaction time, strength, and coordination. Our results indicated that no persistent deficits were seen on distal motor tasks in left-handed adults who suffered a penetrating brain wound. These findings are compatible with the relative sparing of persistent neuropsychological deficits in left-handers following brain damage.     

线方向判断测验在神经内,外科临床的应用与评价

对200名正常人及168例脑损害病人分别进行了线方向判断测验的测查。发现在对照组中,年龄、性别、文化水平对测验成绩均有一定的影响,尤以文化水平的影响最为显著。各病种组与对照组比较,发现脑梗塞组与脑肿瘤组成绩比外伤组和血管畸形组为差。同时还发现所有病种组右脑损害患者分数均低于左脑损害患者。     

空间书写障碍的个案研究

根据书写加工理论,从异形字水平、图解动作模式水平和神经动作执行水平三个方面,综合考察一例空间书写障碍儿童的认知加工特点。结果表明：（1）个案QY的异形字水平出现选择性损伤,在视觉整体特征的知觉加工上存在困难,导致自发书写的汉字难以辨识,存在严重的间架结构问题。（2）个案QY在图解动作模式水平以及神经动作执行水平上表现正常     

Brain Organization of Language after Early Unilateral Lesion: A PET Study

Neuropsychological studies suggest that good long-term language outcome is possible following extensive early left-hemisphere damage. We explored the brain organization for language in children with early unilateral lesion, using [¹⁵O]-water PET. In 12 patients with left lesion (LL) and 9 patients with right lesion (RL), cerebral blood flow changes during listening to sentences and repetition were studied. A rightward shift of language activations in the LL group was found in perisylvian areas and multiple other, mostly temporo-parietal, regions. The hypothesis of intrahemispheric reorganization in the LL group found only limited support. The number of activated regions was overall greater in the RL group. Unexpected findings included a stronger subcortical and cerebellar language involvement in the RL group. We suggest that (a) early left lesion is associated with enhanced language participation of the right hemisphere in and beyond the classical language areas, and (b) postlesional effects are in part additive (recruitment of noncanonical areas), in part subtractive (functional depression in areas normally involved in language).     

Linguistic recovery after closed head injury

Recovery from acute aphasia after closed head injury was studied in 21 young adults at least 6 months after injury. Three profiles of scores were found using standardized language tests. Persistent expressive and receptive impairment was present in 6 patients who sustained severe diffuse brain injury resulting in global cognitive deficit. Residual expressive impairment, primarily of naming, was associated with mild diffuse brain injury though focal left-hemisphere injury was present in 3 of 6 cases. Patients who recovered to normal levels on all language tests generally had acute neurologic findings consistent with mild diffuse brain injury. Cranial computed tomography at the time of followup frequently disclosed ventricular enlargement.     

HEMISPHERE FUNCTION AND SPATIAL ABILITY: AN EXPLORATORY STUDY OF SEX AND CULTURAL DIFFERENCES

Three experiments investigated performance as a function of the visual hemifield to which verbal and spatial stimuli were presented tachistoscopically. The aim was to relate laterality effects to individual, sex and cultural differences in spatial ability within the framework of a model of hemispheric specialisation. A left-hemisphere advantage for verbal materials was obtained but no advantage for right-hemisphere presentation of visuospatial information occurred in the following samples: British and Ghanaian (experiment 1), high and low spatial ability groups (experiment 2) and males and females (experiment 3). Traditional spatial ability tests had no predictive value for performance on the tachistocopic tasks and an interaction between presentation field and responding hand was interpreted as implying equivalent processing of spatial information in either hemisphere.     

Language localization in cases of left temporal lobe arachnoid cyst: evidence against interhemispheric reorganization

We investigated whether left-hemisphere arachnoid cysts lead to reorganization of the language function using PET. A group analysis demonstrated that patients showed no more right-hemisphere activation than a matched control group. Several patients had clear language localizations in the left hemisphere during language comprehension; none of the patients showed right-hemisphere activation. We conclude that left-hemisphere tissue must suffer considerable compromise before reorganization of language into the right hemisphere becomes necessary. Language activations within the left hemisphere are clearly displaced. This is consistent with mere physical displacement in some patients rather than reorganization within the left hemisphere; in others intrahemispheric reorganization cannot be excluded.     

Spoken language correlates of reading impairments acquired in childhood

This study reports the reading difficulties of five children following unilateral left hemisphere stroke sustained either before or during the early stages of literacy acquisition. Although each of the children experienced a period of disturbed language processing in the initial stages postonset, at the time of testing none of the children were considered to be clinically aphasic. Yet, on a standardized test of oral reading each of the children achieved a reading age that lagged behind chronological age and marked reading impairments were disclosed in four of the five children. A set of standardized and nonstandardized tests, aimed at measuring aspects of cognitive and spoken language processing that are considered to be important for normal reading acquisition, was administered. Where nonstandardized tests were used, performance of each of the stroke children was compared to that of groups of normally developing control children, closely matched for chronological age. A range of residual deficits in cognitive and spoken language processing was disclosed among the five brain-damaged children that appeared to be associated with their reading impairments. Two children had expectedly poor reading due to a selective impairment in verbal IQ; a specific phonological reading disorder was revealed in two children, each of which had a residual impairment to phonological awareness; and delayed reading acquisition was observed in one child with a general language deficit. It is suggested that when a child suffers damage to the left hemisphere in the early stages of reading acquisition, difficulties with learning to read are likely to ensue and may arise as a consequence of an underlying cognitive or linguistic deficit.     

Right-hemisphere speech representation and comprehension of syntax after left cerebral injury

Comprehension of language and visuo-spatial abilities were studied in 12 surgical patients with left cerebral lesions and right-hemisphere speech representation verified by sodium amobarbital tests. When left-hemisphere symptoms preceded the acquisition of speech, impaired understanding of syntactically complex sentences was associated with an early, but not late, onset of convulsive seizures. Other behavioral measures did not show a similar effect of age at seizure onset. Sparing or loss of comprehension could not be related to any aspects of the neurological histories in cases with right-hemisphere speech acquired before the onset of left-hemisphere symptoms. Factors which may have influenced the development of right-hemisphere language comprehension are discussed.     

Ipsilesional Arm Motor Sequence Performance After Right and Left Hemisphere Damage

Aiming movements are part of daily activities but the brain hemispheres’ role in targeted aiming sequential movements is not fully clear. Start and execution of discrete and sequential tasks toward targets were analyzed in 10 individuals with left-hemisphere damage, 10 right-hemisphere–damaged, and 10 healthy ones. Arm movements were performed over a digitizing tablet, following stimuli on a monitor, from initial position toward right and left-positioned targets. Poststroke individuals used their ipsilesional arm and healthy individuals, both arms. Right-hemisphere–damaged individuals showed higher reaction time and left-hemisphere–damaged individuals, lower smoothness. Due to spatial demand of tasks, the right hemisphere played a major role in movement planning, while the left, in movement execution.     

Cerebral mechanisms for understanding emotional prosody in speech

Hemispheric contributions to the processing of emotional speech prosody were investigated by comparing adults with a focal lesion involving the right (n = 9) or left (n = 11) hemisphere and adults without brain damage (n = 12). Participants listened to semantically anomalous utterances in three conditions (discrimination, identification, and rating) which assessed their recognition of five prosodic emotions under the influence of different task- and response-selection demands. Findings revealed that right- and left-hemispheric lesions were associated with impaired comprehension of prosody, although possibly for distinct reasons: right-hemisphere compromise produced a more pervasive insensitivity to emotive features of prosodic stimuli, whereas left-hemisphere damage yielded greater difficulties interpreting prosodic representations as a code embedded with language content.     

Online measures of basic language skills in children with early focal brain lesions

Twenty children with early focal lesions were compared with 150 age-matched control subjects on 11 online measures of the basic skills underlying language processing, a digit span task, and 6 standardized measures. Although most of the children with brain injury scored within the normal range on the majority of the tasks, they also had a disproportionately high number of outlier scores on the reaction time tests. This evidence for a moderate impairment of the basic skills underlying language processing contrasts with other evidence suggesting that these children acquire normal control of the functional use of language. Furthermore, these children scored within the normal range on a measure of general cognitive ability, suggesting that there is no particular sparing of linguistic functions at the expense of general cognitive functions. Using the MPD procedure (Valdés-Pérez & Pericliev, 1997), we found that the controls and the five clinical groups could be best distinguished with two measures of online processing (word repetition and visual number naming) and one standardized test subcomponent (the CELF Oral Directions subtest). The 12 children with left hemisphere lesions scored significantly lower than the 8 other children on the CELF-RS measure. Within the group of children with cerebral infarct, the nature of the processing disability could be linked fairly well to site of lesion. Otherwise, there was little relation between site or size of lesion and the pattern of deficit. These results support a model in which damage to the complex functional circuits subserving language leads to only minor deficits in process efficiency, because of the plasticity of developmental processes.     

Memory for words and drawings in children with hemiplegic cerebral palsy

A list-learning paradigm was used to study learning and memory of verbal and figurative material in children with right versus left-sided hemiplegic cerebral palsy. Thirty-one children with right (n=18), or left (n=13) congenital hemiplegia were compared with normal controls (n=19). All children had normal intelligence (IQ>80), and were attending standard schools. The inclusion criteria for the two hemiplegic groups were; no epilepsy, no hearing or visual impairments, and a mild to moderate hemiparesis. The aim of this study was to explore material-specific (words and drawings) differences in the acquisition, recall and serial position effects in children with an early unilateral brain lesion. The left-hemisphere impaired (i.e. right hemiplegia) group showed impaired acquisition for drawings, as compared with the normal controls. There was also a material-specific difference in the serial position effect for all three groups. Learning of words followed the primacy principle, whereas the learning of drawings followed the recency principle. There were no group-differences in delayed-recall (i.e. long-term memory) for either words or drawings. The results are discussed in terms of acquisition and retention of verbal and figurative materials in relation to lesion side and size.     

Neurocognitive outcomes in children with unilateral basal ganglia arterial ischemic stroke and secondary hemidystonia

Dystonia is a movement disorder that involves excessive, involuntary muscle contractions resulting in repetitive movements and/or abnormal posturing. One common cause of unilateral dystonia in childhood is ischemic stroke involving the basal ganglia and/or thalamus. Virtually nothing is known about neuropsychological outcomes in children who have dystonia following basal ganglia stroke. The present study explored whether or not children with secondary dystonia experience additional cognitive challenges when compared to children with similar patterns of brain injury, but no dystonia. We examined intellectual function, academics, and several aspects of executive function in children with unilateral basal ganglia stroke during childhood, comparing those with dystonia and those without. Although groups did not differ in terms of lesion size, we found significantly lower performance on measures of verbal and nonverbal reasoning, inhibitory control, and academic ability in children with secondary dystonia compared to those without. In contrast, there were no significant group differences on parent ratings of their child’s executive function in daily life. These findings suggest that maladaptive reorganization following basal ganglia stroke may contribute to the development of secondary dystonia and also to poor intellectual and academic outcomes in this group.     

Pitch and timing abilities in adult left-hemisphere-dysphasic and right-hemisphere-damaged subjects

The production and perception of pitch and rhythm were tested in patients with acquired unilateral left-hemisphere (LH) lesions (and subsequent motor dysphasia, n = 13), patients with unilateral right-hemisphere (RH) lesions (n = 14), and normal age-matched controls. While the LH dysphasic subjects were not generally impaired on the production or perception of pitch, they were grossly impaired on the production and perception of rhythm. The RH subjects, in contrast, were impaired on measures of pitch perception and production, including the discrimination and production of single notes and of melodies. It is concluded that the two hemispheres differ in their specialization for the perception and production of pitch and rhythm.     

Hemispheric differences for semantically and phonologically primed nouns: A tachistoscopic study in normals

Normal individuals performed two matching tasks. In one task, semantic processing, synonyms had to be recognized. Half the stimuli were picturable and half were nonpicturable nouns. In this task, recognition of picturable synonyms was found to have hemifield symmetry, whereas recognition of nonpicturable synonyms yielded a left-hemisphere superiority, indicating that semantic matching itself did not reveal equal performance of both hemispheres. It is concluded that picturable synonyms might be recognized either by processes of visual imagery, which pertain to right-hemisphere function, or by their phonological or phonic features, which are processed by the left hemisphere. The other task, shown in previous research to exhibit a left-hemisphere superiority, was to decide if two nouns (homophones) were equally pronounced. Here a distinct left-hemisphere advantage was revealed.