Down Syndrome Research and Practice 1998 Abstracts

Down Syndrome Research and Practice 5 (1): 1-15 (1998)

Cases of exceptional language in mental retardation and Down syndrome: Explanatory perspectives

Jean A. Rondal, Ph.D., Dr. Ling.
From a keynote presentation to the 2nd International Conference on Language and Cognitive Development in Down syndrome, Portsmouth, UK, April 8-10, 1997.

Recent studies of exceptional language development and functioning in mentally retarded people raise questions regarding basic issues in language disorders. These studies are summarised and their implications discussed. Possible reasons for the existence of such cases are examined including language training, general cognitive functioning, working memory, cerebral dominance, and deep-seated variation at brain level.

Down Syndrome Research and Practice 5 (3): 105-110 (1998)

Sleep Neurophysiopathology in Down Syndrome

Raffaele Ferri^{a, b}, Lilia Curzi-Dascalova^d, Stefano Del Gracco^b, Maurizio Ella^b, Salvatore Pettinato^c, Sebastiano A. Musumeci^b
^a Sleep Research Center, ^b Department of Neurology, ^c Department of Neurophysics, Oasi Institute for Research on Mental Retardation and Brain Aging, Via Conte Ruggero 73, 94018 Troina Italy. (Tel: +39-935-936111, Fax: +39-935-653327), ^d INSERM, Laboratoire de Physiologie-EF, Hôpital Robert Debré, Paris

In this paper, research on sleep characteristics of subjects with Down syndrome is briefly reviewed and some new data on autonomic function during sleep are reported. Subjects with Down syndrome show a significant reduction in percentage of REM sleep (probably more evident in the most severely retarded subjects), a marked delay in first REM latency and a statistically significant decrease in high-frequency rapid eye movements during REM sleep. The percentage of REM sleep in humans can be considered as an index of brain "plasticity" and the high-frequency REMs can represent an index of the brain ability to organize information; thus, these studies have provided a neurophysiological basis to a psychopedagogical approach for the treatment of learning and memory disabilities in Down syndrome. Moreover, children with Down syndrome show a clearly decreased peak amplitude of growth hormone during sleep; this causes the poor physical development in these subjects and might be related to the occurrence of sleep apnea. Obstructive sleep apnea has also been repeatedly reported in these children; however, if obvious risk factors are absent, children with Down syndrome tend to show the presence of central sleep apnea which is caused by a probable dysfunction of autonomic control at a brainstem level.