Rapid eye movement (REM) sleep measures distinguish elderly patients
with depression from those with dementia. The authors used a 2-night REM
sleep deprivation (RSD) protocol to characterize patients with mixed
symptoms of depression and dementia in comparison with patients with "pure"
depression or dementia and healthy controls. Mixed-symptom patients
resembled dementia patients in baseline sleep measures, but their large
change in phasic REM activity following RSD suggests neurobiological
similarities to depression. Mixed-symptom patients with stable cognitive
impairment had greater REM sleep rebound than those with a more progressive
dementing course. These results are consistent with previous
neuropathological and neurochemical data.Abstract Teaser