The effect of memantine on sleep behaviour in dementia with Lewy bodies and Parkinson's disease dementia.

Objective: Two common and characteristic sleep disturbances have been described in dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD); excessive daytime sleepiness and REM sleep behaviour disorder (RBD). This study is an analysis of a secondary outcome measure of a larger study already reported, aimed to determine whether memantine has an effect on the sleep disturbances in DLB and PDD patients.

Methods: Patients with DLB or PDD were included in a placebo-controlled, randomised controlled study of memantine (20 mg per day) for 24 weeks. The Stavanger Sleep Questionnaire and the Epworth Sleepiness Scale were used to evaluate the effect on sleep disturbances.

Results: Forty two patients started treatment; 20 with memantine and 22 with placebo. The primary analysis was the comparison of change between the two groups during a 24-week period, using the modified ITT population (last observation carried forward). At 24 weeks, patients treated with memantine were less physically active during sleep while patients in the placebo group worsened. Mean difference between the groups (0.5 [0.05-0.90]) was significant (p = 0.006). No significant change was observed in severity of excessive daytime sleepiness.

Conclusions: Memantine decreases probable REM sleep behaviour disorder in patients with DLB and PDD. Both diagnostic groups contributed equally to the outcome.