Sleep disturbance and cognitive disorder: epidemiological analysis in a cohort of 263 patients.

The aim of this study was to investigate and describe frequency and characteristics of sleep disorders in a large cohort of community dwelling persons with several degrees and typologies of cognitive disorders. 236 patients (78 men and 158 women) were enrolled with different subtypes of dementia: Alzheimer's disease (AD), vascular dementia (VaD), mixed dementia, mild cognitive impairment (MCI), dementia with Lewy bodies (DLB), parkinson's disease dementia (PDD), and frontotemporal lobar degeneration (FTLD), respectively. The sleep disturbances evaluated were: insomnia, excessive daytime sleepiness (EDS), REM behavior disorder (RBD), restless legs syndrome (RLS), and nightmares. Every type of sleep disorder was present in each type of dementia but with significant differences. Insomnia is found to be more present and specific for AD; EDS was associated with the presence of dementia in the elderly with LBD or PDD; RLS and nightmares that were recognized mainly in FTD, LBD, and PDD patients scores; patients with MCI had a frequency of sleep disturbances of any type equal to that of patients with AD presenting mostly insomnia, nightmares or RLS more frequently; nightmares were more frequent among LBD and PDD patients. Frequency of RDB was more frequent in FTD, AD, and VaD. Our findings demonstrate that sleep disturbance was related to dementia. A careful clinical evaluation of sleep disorders should be performed routinely in the clinical setting of persons with cognitive decline.