Seventy-two hour polygraphic and behavioral recordings of wakefulness and sleep in a hospital geriatric unit: comparison between demented and nondemented patients.

Continuous 72-h polygraphic recordings were carried out in 30 hospitalized, mostly severely demented patients and 14 nondemented control patients. Mean age was greater than 80 years in both groups. In the dementia group, the diagnoses were senile dementia Alzheimer type (n = 16), multi-infarct dementia (n = 8), and mixed or undefined dementia (MIX) (n = 6). The nondemented controls suffered from various medical or psychiatric disorders or were recovering from previous accidents. Dementia patients had less stage 2 and REM sleep and thus less total sleep time than did control subjects. No statistically significant differences were noted between dementia subgroups. There were no differences between controls and demented patients in terms of NREM-REM cycle, and there was no association between the severity of the clinical condition and any of the sleep parameters in the demented patients. In contrast to healthy elderly and old persons, women and men patients with dementia showed no differences in their sleep patterns. In both patient groups, most sleep occurred at night, and wakefulness was predominant during the day. Only three of the dementia patients displayed somewhat more daytime than nighttime sleep. The main conclusions were that polygraphic sleep recordings did not contribute to a better differential diagnosis in patients with advanced dementia and that inversion of the sleep/wakefulness rhythm was uncommon in these separately roomed demented patients.