Hemispheric specialization in children as reflected in the longitudinal development of ear asymmetry.

The longitudinal development of ear asymmetry has been investigated in two samples of kindergarten and primary school children over an age range of six years. Ear preference in a dichotic digit test, administered four times, did not appear to be affected by age and sex: right ear advantage was predominant at all times. Individual comparison showed the development of ear advantage to depend on initial preference. Initially left eared subjects when changing ear advantage do so from left to right at early and from right to left at later school ages. The left-right shift may be due to the school teaching of linguistic skills which could selectively activate the left cerebral hemisphere. This explanation is supported by the finding that initially right eared subjects tended to conserve that preference at early school ages. Acknowledgements. We would like to thank Mr. P. Borgman and his staff of the Johannesschool in Amsterdam as well as their pupils who did not protest despite being examined year after year. The cooperation of the Free University Audio-Visual Center (Mr. Fred Van Hilst) is kindly acknowledged. Finally we would like to thank Dr. Paul Harris who was willing to read the English text critically and all others who assisted in the completion of this research.

Memory Complaints in Medically Refractory Epilepsy: Relationship to Epilepsy-Related Factors.

This study reports the results of a multicenter study on memory complaints in 252 patients with epilepsy who presented with subjective complaints about memory problems in daily life. Memory complaints were measured with a standardized memory questionnaire (GKLE). The main purpose was to analyze the type of memory complaints and to examine the relationship between subjective complaints and several epilepsy-related factors. These include seizure type, lateralization and location of the focus, etiology, duration, age at onset, and antiepileptic medication. As expected patients experienced significantly more memory complaints. In particular, patients of older age and higher intelligence level complained more about their memory functioning. Although the clinical significance is marginal, neuroticism showed a significant relationship to the total complaint score. The total amount of subjective complaints is not related to the localization or lateralization of the epileptic disturbances. Patients with a longer duration of epilepsy complained significantly more about memory problems, especially about retrieving information from memory. All other epilepsy-related factors showed no relationship to memory complaints.

Dichotic listening ear asymmetry: patterns of longitudinal development.

Dichotic listening research with children has continued to be prevalent although numerous authors have described both theoretical and methodological limitations with traditional dichotic listening free-recall paradigms. The present research adds to this growing skepticism by reanalyzing two major longitudinal studies of children's ear asymmetries. These two studies, based in different countries (United States, Holland), utilized highly similar paradigms (free-recall digits), subjects (males), and age levels (kindergarten and second and fifth grade). The questions of ear advantage development, patterns of ear advantages, and the relationship between dichotic listening performance and reading skills are addressed from the multiple statistical methodologies represented in the literature. From these analyses, support for all of the major hypotheses regarding the developmental patterns of dichotic listening performances could be obtained from the same data samples. The use of traditional free-recall dichotic listening paradigms are not recommended for use with children. The implications for future research are discussed.

Stimulus-governance and the hyperkinetic syndrome.

The hypothesis that hyperkinetic children are stimulus-governed was tested. In a sample of 39 nonmedicated hyperkinetic boys 26 were found to be stimulus-governed. In a control sample of 20 nonmedicated boys 6 were found to be stimulus-governed. An association was found between the hyperkinetic syndrome and stimulus-governance. The hypothesis is raised that response to methylphenidate is related to stimulus-governance. Several issues raised by the research are discussed.

Processing of sentences in aphasia as assessed by eye-movement recordings.

The eye-movements of nine aphasic and nine nonaphasic control patients were recorded while they were looking at slides, containing eight words, selected from four different linguistic categories (nouns, verbs, adjectives, and adverbs). The task was to construct a 4-word sentence. The aphasic patients produced fewer syntactically and semantically correct sentences. Both aphasics and controls used more nouns than adverbs in their sentences. The eye-movement patterns revealed no statistically significant differences between the two groups in terms of fixation time per word category or in terms of fixation time per visual hemispace. Implications for a linguistic theory of sentence processing are discussed.

Eye-movement patterns in disabled readers at two age levels: a test of Bakker's balance model.

The eye-movement patterns of good and poor readers at two age levels during slide-presented reading, arithmetic and perceptual-closure tasks were compared. Older dyslexics were deficient in reading and arithmetic, but performed well on perceptual-closure tasks. Younger dyslexics were deficient on all tasks. Both younger good readers and older poor readers appeared to use a right-hemispheric reading strategy, while older dyslexics appeared to show a left-hemispheric approach. Younger dyslexics did not exhibit any strategy at all. Implications for Bakker's balance model of dyslexia and for subtypes research in dyslexia are discussed.

Relationships between epilepsy-related factors and memory impairment.

OBJECTIVES: In this study, we will explore the effect of epilepsy-related factors such as: 'type of epilepsy, 'site and side of focus localisation' and 'age at onset', as well as four seizure-related factors: 'years with continuing seizures', 'seizure type' and 'seizure frequency', and the treatment factor 'adverse effects of the medication', on memory impairment. Additionally, we explored whether these epilepsy factors are related to different aspects of memory, i.e. short-term recall vs long-term recall, learning, and verbal memory vs non-verbal memory. MATERIAL AND METHODS: A total of 252 patients with epilepsy and subjective memory complaints were consecutively included from the three epilepsy centres in the Netherlands. To assess memory functions the Wechsler Memory Scale-Revised (WMS-r), and the Dutch version of the California Verbal Learning Test for verbal list learning, was administered. RESULTS: A multivariate analysis of variance (MANOVA) did not show statistically significant effects of the epilepsy factors on memory for the total study sample. For the patients with a unilateral epileptogenic focus in the temporal lobes, MANOVA showed statistically significant effects of lateralisation, with most impairment for patients with left temporal lobe epilepsy and, independently, seizure frequency and 'years with seizures'. CONCLUSION: We may conclude that epilepsy-related dysfunctions in the temporal lobe are the dominant risk factor for developing memory problems, specifically verbal memory problems (verbal learning and problems consolidating verbal information), with more severe impairments with continuing seizures and when seizure frequency is high.