REM-Sleep in patients with dementia of Alzheimer and frontotemporal type under long term treatment with cholinesterase inhibitors

Besides cognitive impairment, patients with dementia commonly present with a sleep disturbance. The most robust polysomnographic finding in Alzheimer’s dementia (DAT) is reduction of REM-sleep. Cholinsterase inhibitors (Che-I) are able to increase REM-sleep in volunteers. The objective of this study was to evaluate the effects of Che-I on REM-sleep in DAT and frontotemporal dementia (FTD) during long-term treatment. So far, 13 patients with low to moderate dementia could be examined. 7 patients were classified as having DAT and 6 patients as having FTD. A polysomnography was performed in all patients who were free of psychotropic medication before therapy with a Che-I and after 5–10 months, while patients were on monotherapy with a Che-I. In all patients sleep continuity disruption was observed. In DAT a more accentuated REM sleep reduction in comparison to FTD was found. Treatment with Che-I did not improve sleep continuity. However, REM-sleep increased in patients with DAT, but not in patients with FTD. Furthermore, REM-latency was reduced in DAT after treatment with Che-I. The observed REM-sleep reduction in patients with DAT compared to FTD may suggest that cholinergic neurotransmission is more impaired in DAT than in FTD. However, it remains unclear whether the increase of REM-sleep after long-term treatment with Che-I in DAT may only reflect a mere pharmacological effect or whether this increase may be related to the efficacy of anti-dementia treatment