title: Down's syndrome: a study of sleep patterns related to level of mental retardation.
mesh_terms: D000293:Adolescent; D002648:Child; D004314:Down Syndrome; D004325:Dreams; D004569:Electroencephalography; D004576:Electromyography; D004585:Electrooculography; D006801:Humans; D008607:Intellectual Disability / Q000209:etiology*; D008297:Male; D011574:Psychoanalytic Theory; D012701:Serotonin / Q000097:blood*; D012894:Sleep Stages; D012895:Sleep, REM
chemical_list: D012701:Serotonin