Georgia Andreou

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.

Cerebellum and Reading

Background: Traditionally, the cerebellum has been considered to control coordinated movement. However, in recent years it has been argued that it contributes to higher cognitive functions. Objectives: This review aims to present recent evidence concerning the role of the cerebellum and discusses how it can contribute to reading. Method: The procedure used involves findings coming from three quite different areas, lesion, anatomic and functional imaging studies. Results: These studies indicate a link between cerebellum and reading and its relationship with specific reading difficulties. Conclusions: Our review provides evidence which is in accordance with the recently established role of the cerebellum as a regulator of mental functions and supports theoretical models suggesting that cerebellar deficits might be a cause of developmental dyslexia.

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.

Effects of chronic obstructive pulmonary disease and obstructive sleep apnea on cognitive functions: evidence for a common nature.

Patients with chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea syndrome (OSAS) show similar neurocognitive impairments. Effects are more apparent in severe cases, whereas in moderate and mild cases the effects are equivocal. The exact mechanism that causes cognitive dysfunctions in both diseases is still unknown and only suggestions have been made for each disease separately. The primary objective of this review is to present COPD and OSAS impact on cognitive functions. Secondly, it aims to examine the potential mechanisms by which COPD and OSAS can be linked and provide evidence for a common nature that affects cognitive functions in both diseases. Patients with COPD and OSAS compared to normal distribution show significant deficits in the cognitive abilities of attention, psychomotor speed, memory and learning, visuospatial and constructional abilities, executive skills, and language. The severity of these deficits in OSAS seems to correlate with the physiological events such as sleep defragmentation, apnea/hypopnea index, and hypoxemia, whereas cognitive impairments in COPD are associated with hypoventilation, hypoxemia, and hypercapnia. These factors as well as vascocerebral diseases and changes in systemic hemodynamic seem to act in an intermingling and synergistic way on the cause of cognitive dysfunctions in both diseases. However, low blood oxygen pressure seems to be the dominant factor that contributes to the presence of cognitive deficits in both COPD and OSAS.

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.

Verbal fluency in adults diagnosed with attention-deficit hyperactivity disorder (ADHD) in childhood.

It has been increasingly believed that attention-deficit hyperactivity disorder (ADHD) is a disorder with lifelong course associated with cognitive difficulties including among others, language production, verbal learning, and verbal fluency. However, research is limited to children and adolescents, and very few researchers have examined the impact of ADHD in adulthood on the cognitive domain. The aim of the present study is to examine the performance of adults, diagnosed with ADHD in childhood, on semantic and phonemic verbal fluency tasks. It is hypothesized that adults with ADHD will perform worse on both tasks than matched controls. Sixty university students (30 diagnosed with ADHD in childhood and 30 matched controls) of mean age 20.5 participated in the study. They all completed two verbal fluency tasks. The ADHD group had statistically significant lower scores than the non-ADHD group on the phonemic, but not the semantic task. The study provides some evidence that ADHD in childhood has a negative impact on adults’ phonemic verbal fluency. This finding could be probably explained by the fact that phonemic fluency is considered more cognitively demanding and impacting more on the frontal lobe functions, known to be impaired in ADHD, than semantic fluency.

Left-handedness in asthmatic children

Left‐handedness has been associated with asthma and allergic disorders. The Geschwind–Behan–Galaburda (GBG) hypothesis could explain this association. In view of previous findings, we investigated the distribution of laterality scores among asthmatic children and controls aged 4–8 years old. Seventy families with asthmatic children were administered the International Study of Asthma and Allergy in Childhood (ISAAC) questionnaire and the Edinburgh Left‐handedness Inventory. A sample of 70 families with non‐asthmatic, healthy children was used as controls. The majority of children had mild asthma. Ambidexterity was the main feature in the asthmatic children. A statistically significant difference in the laterality quotient (LQ) distribution was found in the group of asthmatic children with allergic rhinitis (LQ mean value in the asthmatic children with allergic rhinitis: 42.85 vs. 79.50 in the rest of the asthmatic children). These results suggest that there is a tendency towards left‐handedness in asthmatic children and lend support to the GBG hypothesis.

Biological and environmental influences in visuospatial abilities.

Abstract Sex differences in cognition have been the focus of intense debate for years. In this study, we examined the hypothesis that the pattern of sex differences in a visuospatial task may be differential due to environmental factors such as the participation of females in technical and scientific courses. A total of 452 undergraduate students (146 males and 306 females) participated in this study. Results showed a significant effect of academic discipline on both Rey–Osterrieth Complex Figure (ROCF) copy and recall scores. Significant effects of gender were found only on the recall condition. This pattern of results indicates that both gender and academic discipline may influence the performance on a visuospatial task such as ROCF.

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.