Sleep Symptoms Differentially Predict Cognition in Younger and Older-Onset Parkinson's Disease

Maria Pushpanathan, Andrea Loftus, Natalie Gasson, Meghan Thomas, Romola Bucks

Research output: Contribution to journalArticle


Background: Both disrupted sleep and cognitive impairment are frequent in Parkinson’s disease (PD), but the evidence for a relationship between self-reported sleep disturbance and cognitive symptoms has been equivocal. If sleep symptoms differentially predict cognition in different subtypes, effects may be obscured in a general PD sample.

Objective: First, to determine whether the associations between participant and disease variables, sleep symptoms and cognitive performance vary by subtype (younger and older-onset); then to establish whether these effects remain when the sample is reanalysed as a whole.

Methods: Multi-group path analyses were used to model the relationships between participant and PD variables; factor scores derived from our bifactor analysis of the Parkinson's Disease Sleep Scale-Revised; and, measures of memory and executive function. Path analyses were replicated as single group analyses.

Results: Increased general sleep disturbance predicted better verbal recall in younger-onset PD and poorer visual episodic memory in older-onset PD. Increased insomnia scores predicted better verbal recognition memory in younger-onset PD, better verbal fluency in both groups and poorer spatial working memory (SWM) in older-onset PD. Higher OSA and RBD scores predicted poorer spatial recognition memory and spatial working memory in younger-onset PD, but did not predict cognition in older-onset PD. Many regression coefficients were weakened or reduced to non-significance in the single-sample models.

Conclusions: The relationships between participant variables, sleep, and cognition were markedly different in younger and older-onset PD. The influence of sex and premorbid IQ as moderating variables warrant further investigation.
Original languageEnglish
JournalOBM Geriatrics
Issue number3
Publication statusPublished - 23 Sep 2019

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