Upper limb motor function in young adults with spina bifida and hydrocephalus.

OBJECTIVE: The objective of the study was to measure upper limb motor function in young adults with spina bifida meningomyelocele (SBM) and typically developing age peers. METHOD: Participants were 26 young adults with SBM, with a Verbal or Performance IQ score of at least 70 on the Wechsler scales, and 27 age- and gender-matched controls. Four upper limb motor function tasks were performed under four different visual and cognitive challenge conditions. Motor independence was assessed by questionnaire. RESULTS: Fewer SBM than control participants obtained perfect posture and rebound scores. The SBM group performed less accurately and was more disrupted by cognitive challenge than controls on limb dysmetria tasks. The SBM group was slower than controls on the diadochokinesis task. Adaptive motor independence was related to one upper limb motor task, arm posture, and upper rather than lower spinal lesions were associated with less motor independence. CONCLUSIONS: Young adults with SBM have significant limitations in upper limb function and are more disrupted by some challenges while performing upper limb motor tasks. Within the group of young adults with SBM, upper spinal lesions compromise motor independence more than lower spinal lesions.

Neuropsychological sequelae of the treatment of children with medulloblastoma.

When a malignant tumor invades the child's cerebellum, the cost of successful treatment is often significant cognitive morbidity. A review of neuropsychological outcome revealed that survivors of childhood medulloblastoma (MB) have long-term deficits in intelligence, memory, language, attention, academic skills, psychosocial function, and a compromised quality of life. These deficits varied with chronological age at tumor diagnosis and/or adjuvant treatment, type and duration of presenting symptoms, tumor extension beyond the cerebellum, a history of adjuvant radiation treatment, and time since treatment. The effects on neuropsychological outcome of other factors, such as post-surgical hydrocephalus, were less clear. To understand the interaction between two factors predictive of outcome, age at diagnosis and time since treatment, we analyzed IQ results for a new sample of 25 surgically-treated and radiated MB survivors, and found that age at diagnosis and time since treatment made separable contributions to intellectual morbidity. PIQ appeared to measure some general effects of diffuse cerebral insult because it varied with chronological age of the child at tumor diagnosis but was relatively constant in magnitude, once established. VIQ, in contrast, was somewhat less sensitive to age at diagnosis in treated MB survivors, but declined with time since treatment. These results are important for understanding the academic attainments and continuing rehabilitation needs of childhood MB survivors, because they suggest that these children progressively fail to assimilate new verbally-based knowledge at a developmentally-appropriate rate.

Brain tumors in children and adolescents--III. Effects of radiation and hormone status on intelligence and on working, associative and serial-order memory.

The effects on intelligence and memory of two post-surgical conditions (radiation treatment, hormone deficiency and supplementation) were explored in 46 children and adolescents with tumors in a variety of brain sites. Verbal intelligence, but not non-verbal intelligence, varied positively with age at radiation treatment. Memory for word meanings was unrelated to either radiation history or to hormone status. Severe deficits in serial position memory occurred with impaired hormone function and an older age at tumor onset. Severe deficits in working memory were associated with a history of radiation and a principal tumor site that involved thalamic/epithalamic brain regions. Radiation treatment and hormone status affect later cognitive function in children and adolescents with brain tumors. Although the greater vulnerability of the verbal intelligence of the younger radiated child and the serial order memory of the child with later tumor onset and hormone disturbances remain to be explained, and although the form of the relationship between radiation and tumor site is not fully understood, the data highlight the need to consider the cognitive consequences of pediatric brain tumors according to a set of markers that include maturational rate, hormone status, radiation history, and principal site of the tumor.

Brain tumors in children and adolescents--I. Effects on working, associative and serial-order memory of IQ, age at tumor onset and age of tumor.

Memory impairment was demonstrated in a sample of 46 children and adolescents with brain tumors. The overall distribution of memory scores was skewed positively; over half of the total number of test measures were in the lowest quarter of the score distribution; and more than three-quarters of the individual subjects had at least one memory score in the impaired range. Verbal intelligence accounted for less than one-quarter of the variance in memory scores. The type of memory impairment was analyzed in relation to various demographic and medical variables: age at onset of tumor symptoms, age or duration of tumor, sex, pre-tumor developmental disturbances, pre-tumor closed head injury, post-tumor anticonvulsant treatment and post-tumor epileptic seizures. The working memory task, in which each in a succession of heard words is stored in temporary memory long enough to be compared to or contrasted with incoming words, was unaffected by these variables, as was memory for semantically-based word-picture associations. Memory for the serial order of pictures that corresponded to heard words varied inversely with the age at tumor onset such that the later the onset, the lower the memory test performance.

Brain tumors in children and adolescents--II. The neuroanatomy of deficits in working, associative and serial-order memory.

The neuroanatomy of memory deficits was studied in 46 children and adolescents with brain tumors. CT-scan reconstructions of 88 brain regions were coded with respect to tumor and related damage, and multiple regression procedures established patterns of brain damage predictive of memory deficits. Two forms of memory revealed non-overlapping focal neuroanatomical substrates: memory for the serial order of pictures that corresponded to heard words involved structures in the limbic system and hypothalamic-pituitary axis; whereas working memory, in which each of a succession of heard words is stored in temporary memory long enough to be compared to or contrasted with incoming words, involved the pineal-habenular region and the anterior and medial thalamic nuclei. Memory for semantically-based word-picture associations, in contrast, was unaffected by tumors in several subcortical brain regions. These data bear on current analyses of the neural substrates of associative and representational memory.

Incidence of left-handed writing in a college population with reference to family patterns of hand preference.

Hand preference data were obtained for 1816 university students, 4793 siblings and 3632 parents. Results support the following conclusions. (1) There is currently a 13.8% incidence of left handedness among young adults, representing a dramatic increase over past generations. (2) Left and right-handed respondents do not differ in terms of familial sinistrality. (3) Mother's left-handedness is associated with an increase in the incidence of sinistrality for sons and daughters, while father's left handedness is related only to sons.

Evidence for the sequential participation of inferior temporal cortex and amygdala in the acquisition of stimulus-reward associations.

On a test of one-trial learning of object-reward associations, monkeys showed marked impairment after lesions of either the anterior part of inferior temporal cortex (area TE) or the amygdala (A). By contrast, little or no loss followed lesions of either the posterior part of inferior temporal cortex (area TEO) or the fusiform-hippocampal gyrus and hippocampus (FHH). The finding of impairment after either the area TE or A lesions fits the view [11] that stimulus-reward learning in vision is mediated by a functional chain connecting the visual system to the limbic system through relays in the inferior temporal cortex and the amygdala. Area TE is considered to be the last purely visual link in this pathway. A previous study [19] showed that damage to area TE, but not to other temporal lobe structures (TEO, A or FHH), severely impairs performance on a one-trial-learning test of object recognition as distinguished from object-reward association. Presumably, the impairment after TE lesions in the present study was due to this same basic recognition disorder. The impairment after amygdalectomy, however, not being attributable to a recognition disorder, appears to reflect instead a disorder in object-reward association learning. Together, these results provide evidence that the formation of object-reward associations in vision involves the sequential participation of a recognition mechanism dependent on the inferior temporal cortex and an associative process dependent on the amygdala.