Anomalies paroxystiques nocturnes et troubles de l'apprentissage

This study concerns the analysis of polysomnographic recordings in 33 children suffered from cognitive disorders. In this group, we distinguish nine cases of dysphasia (expressive trouble in four cases and phonological-syntaxic trouble in five cases), twenty-one cases of dyslexia and three cases of developmental dyspraxia. All the children underwent a detailed neuro-psychological evaluation, an examination by NMR, a standard EEG and a polysomnographic recording including symmetrical fronto-rolandic, fronto-temporal, temporo-occipital EEG channels, electro-oculogram, electrocardiogram and electromyogram (chin muscles). The aim of the study, on one hand is to describe paroxysmal activity during sleep, their localisation, density, and distribution in the different sleep stages. On the other hand is to compare the sleep architecture with the results obtained in a control group of 20 normal age-matched children. We observed on the 33 children, paroxystical abnormalities in 19 cases (57.5%). The duration of the abnormalities varied from 4 to 90% of the total sleep time (TST) and was longer than 10% of the TST in 12 cases (36%). The sleep architecture was altered with a significative reduction of the TST and a significative augmentation of the duration of the sleep arousals. Our results are compared to those obtained by the same team (Chéliout-Héraut and al. 1992, 1999, Picard and al. 1998) in children suffering from dysphasia. The existence of paroxystical abnormalities was also described during sleep in children suffering from language disorders or cognitive dysfunctions by other authors (Echenne and al. 1990, 1992, John and Nasr 2001). The presence of such anomalies is discussed in the pathophysiology of these large cognitive disorders.