Harry van der Vlugt

The reliability of dichotic ear asymmetry in normal children

Abstract Two, three and four pair dichotic digit tests were presented twice to 250 normal kindergarten and primary school children. Test-retest as well as inter-test reliability and consistency coefficients were calculated. Their values were shown to match similar indices found in normal adults.

Pathological left-handedness: cross-cultural tests of a model.

Abstract The present paper presents a test of a model which attempts to account for the raised incidence of manifest left-handedness (MLH) in epileptic and mentally retarded populations. The results, based on four cross-cultural studies, provides additional support for the model which predicts that this raised incidence of MLH is due largely to unilateral (left) rather than bilateral hemispheric dysfunction.

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.

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 childrens 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.

Learning Disability Subtypes and the Role of Attention During the Naming of Pictures and Words: An Event-Related Potential Analysis

The role of attention in the processing of pictures and words was investigated for a group of normally achieving children and for groups of learning disability subtypes that were defined by deficient performance on tests of reading and spelling (Group RS) and of arithmetic (Group A). An event-related potential (ERP) recording paradigm was employed in which the children were required to attend to and name either pictures or words that were presented individually or in superimposed picture-word arrays that varied in degree of semantic relation. For Group RS, the ERP waves to words, both presented individually or attended in the superimposed array, exhibited reduced N450 amplitude relative to controls, whereas their ERP waves to pictures were normal. This suggests that the word-naming deficiency for Group RS is not a selective attention deficit but rather a specific linguistic deficit that develops at a later stage of processing. In contrast to Group RS and controls, Group A did not exhibit reliable early frontal negative waves (N280) to the superimposed pictures and words, an effect that may reflect a selective attention deficit for these children that develops at an early stage of visuo-spatial processing. These early processing differences were also evident in smaller amplitude N450 waves for Group A when naming either pictures or words in the superimposed arrays.

White matter changes on ct brain scan are associated with neurobehavioral dysfunction in children with symptomatic HIV disease

Abstract The effect of white matter abnormalities on neurobehavioral dysfunction was investigated in 58 children with symptomatic HIV-1 disease, 28 with CT white matter abnormalities and 30 matched (for age, gender, route of infection, and stage of disease) control patients with comparable levels of cortical atrophy, but no white matter abnormalities. Children with white matter abnormalities were more impaired on measures of general level of mental functioning (standard scores of 70.3 vs. 86.1; p < .05). They also scored lower than the group without white matter abnormalities on activities of daily living (76.9 vs. 87.4; p < .05), particularly those requiring self-help skills, and in socialization (79.5 vs. 89.3; p < .05). Furthermore, patients with white matter abnormalities exhibited higher levels of attention deficit/hyperactive behaviors (p < .05) and more severe autistic symptoms (p < .05). White matter abnormalities by themselves were, thus, associated with deficits in cognitive function and socio-e...

Aspects of Normal and Abnormal Neuropsychological Development

Research in developmental neuropsychology has emphasized empirical methods and differences in methodology have probably restricted broader conceptual understanding. Moreover, attention has too often been focused on isolated tests purporting to measure left-right discrimination, form perception, writing, and calculation. This state of affairs has generated a plethora of studies into specific developmental disorders, but these are often based on unrepresentative cases, inadequate design, and isolated behaviors. Theory development has been slow, thus preventing the conceptual integration of findings which appear unrelated or discrepant with specific hypotheses.

Intelligence, learning disabilities, and event‐related potentials

The current status of research on learning disabilities (LD) and intelligence in children using event‐related potential (ERP) methods is outlined. Consistent with behavioral and psychophysical assessments of sensory capabilities, exogenous sensory ERPs do not show compelling evidence of a relation to measures of either intelligence or LD. With normal adult samples, there is some evidence that higher mental ability is associated with shorter ERP latency on sensory and elementary cognitive discrimination tasks that elicit an endogenous, late positive (P3) ERP wave. Children with reading disabilities (RD) exhibit longer P3 latency and smaller P3 amplitude than normal controls to linguistic target stimuli, but individuals with RD are not differentiated from normal controls on simple sensory discrimination ERP paradigms. The importance of classifying subtypes of LD was evident in several studies. In particular, a fronto‐central negative wave at 450 ms was successful in distinguishing LD subtypes in several par...

Analysis of eye-movement recordings

Abstract This report describes a technique for the analysis of eye-movement recordings. The recordings themselves are described first; this is followed by a description of our methods of analysis. Throughout, an attempt is made to focus on the features of this technique and the analytic methods that can be used with it, as these relate to studies of a clinical neuropsychological nature that can be carried out with adults as well as with children.

Recognition memory of serially or simultaneously presented words or figures, of epilepsy patients with or without mesial temporal sclerosis.

Previous studies, examining short-term recognition memory in patients with partial seizures as a consequence of mesial temporal sclerosis (MTS) have reported inconsistent findings. Dependent on the paradigms used for measuring recognition memory, some studies have demonstrated that the mesial temporal structures are not critically involved in short-term recognition memory. In addition, other studies found a lateralization effect that is consistent with the generally accepted association between left temporal lobe lesions and verbal memory deficits, and right temporal lobe lesions and non-verbal memory impairments. In the present study verbal and non-verbal recognition memory was tested in 41 patients with left or right temporal lobe epilepsy with MTS (22 left; 19 right) versus 44 patients with left or right temporal lobe epilepsy but without MTS (28 left; 16 right). Verbal and non-verbal recognition tasks were presented in both a serial and simultaneous condition to test a hypothesized local/global paradigm. Multiple analyses of variance (MANOVA) showed that unilateral MTS has no marked effects on verbal or non-verbal recognition memory of patients with seizures. An interaction effect between MTS and the lateralization of epileptic activity was found on memory performance: MTS only leads to deficits in recognition memory in patients with right-sided epileptiform activity. As hypothesized, patients with left temporal lobe abnormalities, have specific deficits with recognizing serially presented information.