Assessment and Management of "Sundowning" Phenomena.

Approximately one quarter of patients with AD-type dementia reportedly exhibit disruptive, restless, and/or confused behavior that tends to be more apparent in late afternoon or early evening. Research has yet to document the phenomenon in a definitive manner to facilitate standardized assessment and clinical trials. Recent work attempting to define precisely the prevalence of abnormal behaviors during different periods of time of day in AD patients is reviewed. Caregiver reports of confusion and aggressive, disruptive behavior have been associated with going to bed early, increased use of sedative-hypnotics, and more severe cognitive impairment. Because there is evidence that the sleep of many AD patients is of poor quality, one might try to treat such patients with behavioral approaches useful in insomnia in other populations. Futhermore, as psychotropic medications can adversely affect sleep and/or have "hangover" effects on daytime cognition, one should carefully manage these medications to optimize care. Advances in assessment of sundowning, combined with longitudinal studies of sleep and circadian rhythm changes associated with dementia progression, should enhance efforts to treat behavioral and sleep disturbances.