Mentally retarded children present a reduction in percentage of REM sleep and of oculomotor frequencies. These sleep patterns are probably relevant for their cognitive activities. The effects of butoctamide hydrogen succinate and intensive learning sessions on the night sleep of five Down's syndrome patients was studied by the authors. They found an increase in percentage of REM sleep after pharmacological treatment and an increase in oculomotor frequencies after learning sessions. The authors' hypotheses of REM sleep as a neurophysiological indicator of cerebral "plasticity" and of oculomotor frequencies as an indicator of "organization" abilities are discussed in this article. Pedagogical implications and therapeutical perspectives are also outlined.
