The Pathophysiology of the Rett Syndrome from the Standpoint of Polysomnography

Twelve polysomnographies were performed on eight cases of the Rett syndrome and the results were compared between cases under and over 5 years of age. There observed an increase in the ratio of stage REM (sREM) against slow wave sleep (SWS) with age. The ratio of the number of mentalis twitch movement (ment TM) during sREM against the number of rapid eye movements (REMs) (reflecting dopaminergic activities) was below normal in the younger cases but increased markedly. The ratio of ment TM in the period of REMs burst against the total ment TM during sREM (reflecting the noradrenergic hypofunction) was high in the younger group, while it decreased later. The nocturnal variation became inapparent with age in % SWS and the phasic components of sREM, while that of % sREM exaggerated at later ages. The early hypofunctions of the noradrenergic and dopaminergic neurons later modified by the serotonergic dysfunction and dopaminergic postsynaptic supersensitivity are suggested.