EEG REACTIVITY CORRELATES WITH NEUROPSYCHOLOGICAL TEST-SCORES IN DOWNS-SYNDROME

Introduction - Down's syndrome patients express a neurodegenerative di sorder and mental retardation. We studied the reactivity of EEG and it s correlation with neuropsychological test score in Down's syndrome. M aterial and methods - We studied 32 patients with Down's syndrome and 31 controls for blocking of occipital EEC activity. The temporo-occipi tal EEG with eyes open (EOI was compared with resting EEG with eyes cl osed (EC), (EC/EO, ratio), Results - Both Down patients and controls s howed significant diminution of alpha, beta and theta activity and dec rease of EEG frequency with EO. However, there was a significant impai rment in Down patients in the EC/EO ratio in alpha band, compared to c ontrols. The controls had no correlation of the alpha EC/EO ratio with age or gender. The Down patients showed a significant correlation of Ibis variable with age which is in accordance with a gradually progres sing disease. They bad also significant correlations of the alpha EC/E O ratio and neuropsychological test scores which indicates that this r atio may be a more general measure of cerebral or hemispherical dysfun ction than a mere impairment of visual activation, Down patients also showed significant differences in resting EEG variables, compared to t he controls, even if the conventional EEG showed normal or mildly slow ed dominant occipital rhythm in most of the patients. The correlation analysis between resting EEG and EC/EO ratio variables pointed out tha t they are relatively independent, representing different factors in t he regulation of EEG, Conclusions - We believe that the alpha EC/EO ra tio of EEG add a new domain in the assessment of cerebral dysfunction in Down's syndrome.