Depressive symptoms are associated with daytime sleepiness and subjective sleep quality in dementia with Lewy bodies.

Greg J Elder,John‐Paul Taylor,John T O'Brien,Ian G Mckeith,Sean J Colloby,David J Burn,Kirstie N Anderson,Debra J Lett

doi:10.1002/gps.4389

Abstract

ObjectiveSleep problems and depression are common symptoms in dementia with Lewy bodies (DLB), where patients typically experience subjectively poor sleep quality, fatigue and excessive daytime sleepiness. However, whilst sleep disturbances have been linked to depression, this relationship has not received much attention in DLB. The present cross‐sectional study addresses this by examining whether depressive symptoms are specifically associated with subjective sleep quality and daytime sleepiness in DLB, and by examining other contributory factors.MethodsDLB patients (n = 32) completed the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS) and the 15‐item Geriatric Depression Scale (GDS‐15). Motor and cognitive functioning was also assessed. Pearson correlations were used to assess the relationship between GDS‐15, ESS and PSQI scores.ResultsGDS‐15 scores were positively associated with both ESS (r = 0.51, p < 0.01) and PSQI (r = 0.59, p < 0.001) scores.ConclusionsSubjective poor sleep and daytime sleepiness were associated with depressive symptoms in DLB. Given the cross‐sectional nature of the present study, the directionality of this relationship cannot be determined, although this association did not appear to be mediated by sleep quality or daytime sleepiness. Nevertheless, these findings have clinical relevance; daytime sleepiness or poor sleep quality might indicate depression in DLB, and subsequent work should examine whether the treatment of depression can reduce excessive daytime sleepiness and improve sleep quality in DLB patients. Alternatively, more rigorous screening for sleep problems in DLB might assist the treatment of depression. © 2015 The Authors. International Journal of Geriatric Psychiatry published by John Wiley & Sons, Ltd.

Highlights

Dementia with Lewy bodies (DLB) is a common cause of dementia and accounts for 15–20% of all dementia cases post-mortem (Holmes et al, 1999)
International Journal of Geriatric Psychiatry published by John Wiley & Sons, Ltd
A separate study did not observe a relationship between objective intra-individual measures of cognitive fluctuation, and intra-individual measures of objective alertness, as determined by a maintenance of wakefulness test (Bliwise et al, 2014), and it may be that cognitive fluctuations are not directly related to sleep or arousal. These results indicate that sleep problems are associated with depression, which is common in DLB (Fritze et al, 2011), suggesting that excessive daytime sleepiness or poor sleep quality may be a sign of depression in DLB

Summary

Introduction

Dementia with Lewy bodies (DLB) is a common cause of dementia and accounts for 15–20% of all dementia cases post-mortem (Holmes et al, 1999). Sleep disturbances are extremely common in individuals with DLB, where the main sleep problem is REM behaviour disorder (RBD), which refers to the inability to maintain muscle atonia during REM sleep. This symptom has been investigated in detail: RBD can predate the occurrence of Lewy body disease, is associated with various DLB clinical and pathological features and may have a prevalence of up to 70% in this condition (Ferman et al, 2004; Dugger et al, 2012; Iranzo et al, 2013; Murray et al, 2013; Ferman et al, 2014).

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