A. Karapetsas

Cognitive status in Down syndrome individuals with sleep disordered breathing deficits (SDB)

Twelve subjects with Down syndrome underwent polysomnographic studies during night sleep and performed the Mini-Mental state test and the Raven Progressive Matrices (RPM), sets A, B, and B(1). Sleep-disordered breathing (SDB) deficits were observed in Down syndrome individuals and their Mini-Mental and RPM scores were extremely low. Regression analysis of the results revealed that the number of apneas per hour was related with the results of the RPM, set A, which were also related with the orientation of Mini-Mental test, indicating that the more apneas an individual has the more difficulties he has in the kind of visuoperceptual skills, including orientation, associated with normal right hemisphere functioning, which are tested by set A of the RPM.

Verbal skills in children with ADHD

The present study examined whether ADHD children exhibit low verbal IQ (VIQ) and distinguishable test profile on the Verbal comprehension (VC) and Freedom from distractibility (FFD) factors, and whether gender influences their verbal abilities. At the Laboratory of Neuropsychology of the Department of Special Education, University of Thessaly, WISC‐III verbal scales were administered to 69 ADHD children (50 boys and 19 girls) and controls who were matched for age and sex. Mean scores for all WISC‐III verbal scales, VIQ, VC and FFD of ADHD children were significantly lower than controls. FFD was found lower than VC and it correlated statistically significantly with VC in ADHD children. No gender differences were found among ADHD children.

Sex and handedness in development of visuomotor skills

Development of visuomotor skills in 420 left-handed and 420 right-handed school children were investigated using the Rey-Osterrieth Complex Figure. Analysis indicate that the visuomotor skills involved in copying a complex figure improve with age until the mean age of 10.5 yr., in both sex and handedness groups. Further analysis showed that girls performed significantly better than boys at certain developmental stages and right-handers performed better than left-handers in various age groups. Some possible differences in performance could be attributed to different rates of maturation of the cerebral hemispheres, to different neuropsychological strategies, or to functional differences between the sex groups and between right- and left-handed children.

Visuomotor organization in the child: a neuropsychological approach.

The ability of children to copy a complex figure was investigated by means of the Rey-Osterrieth complex figure and the corresponding methodology. The sample consisted of 420 children (boys and girls) aged 5½ to 12½ years. Responses indicate that the visuomotor ability involved in copying a complex figure increases with increasing age and that girls show significantly better performance than boys during the ages 8½ to 12½ years. The differences in performance can be attributed to differential neuropsychological strategies or functional differences that require further investigation.

Verbal Abilities in Low and Highly Proficient Bilinguals

The study investigated native language verbal skills among low and highly proficient bilinguals, using the WISC III verbal subtests. Highly proficient bilinguals showed a superiority for almost all verbal subtests. This finding lends support to Threshold Theory which maintains that bilinguals need to achieve high levels of linguistic proficiency before bilingualism can promote cognitive development. Our study also shows that verbal ability underlying proficiency in the native language can be generalized to a foreign language, revealing a causal connection between native and foreign language learning.

A DEVELOPMENTAL STUDY OF HANDEDNESS IN DOWN SYNDROME PUPILS

Assessed hand preference in 7- to 9-yr.-old and 13- to 15-yr.-old pupils with Down syndrome (n = 41) was compared with control schoolchildren (n = 50) of the same ages. A significant increase in left-handedness and mixed-handedness was noted in Down syndrome groups compared with the normal population. Younger Down syndrome pupils were less consistent in their hand preference than the older pupils and the normal controls.

Hemispheric asymmetries of visual ERPs in left-handed bilinguals

ERPs (N1, P1, N2, P2) obtained from left and right occipital and temporal lobes were elicited in 30 left-handed highly proficient bilingual males in response to visually presented linguistic stimuli. The absence of statistically significant(P = < or =0.05) differences between left and right occipital and temporal lobes in all the components of the waveforms obtained, indicates a bilateral pattern of lateralization in left-handed males for both their native and foreign language.

LEFT-HANDEDNESS AND INHERITANCE OF BRONCHIAL ASTHMA

A statistically significant difference in mean laterality quotients of 15 asthmatic and 106 nonasthmatic children showed a coexistence of left-handedness and asthma early in life. It is suggested that this phenomenon is not only a fetal event as the Geschwind-Galaburda hypothesis claims but it is mainly based on maternal line inheritance.

VISUOMOTOR ORGANIZATION IN THE LEFT-HANDED CHILD-A NEUROPSYCHOLOGICAL APPROACH

In this study we used the Rey-Osterrieth complex figure to examine the visuomotor organization of 514 boys and girls, aged 5.5 to 20.5 yr. All were left-handed as judged by the Edinburgh Handedness Inventory. Statistical evaluation showed significant differences in the visuomotor organization for boys and girls across the various age groups. Statistically significant differences also appeared between the two sexes at the age groups 7.5 to 8.5 and 8.5 to 9.5, with girls showing better organization than boys.

Cognitive Development of Fluent and Nonfluent Bilingual Speakers Assessed with Tachistoscopic Techniques

A tachistoscopic study investigated verbal skills among bilingual speakers, 10 fluent and 15 nonfluent, on rhyming and semantic tasks in both their native (Greek) and second (English) languages. Fluent bilinguals scored higher on all tasks, especially on the English rhyming and the Greek semantic tasks. They also responded faster, especially on the English semantic task. Fluent bilingual speakers scored higher on the Uses of Objects Test, an index of creativity. Nonfluent bilinguals had higher grades in geometry and arithmetic at school while fluent bilinguals had higher grades in Greek composition.