Sleep Disturbance in Mild Cognitive Impairment and Association With Cognitive Functioning. A Case-Control Study.

Katie Palmer,Francesca Burgio,Annalena Venneri,Micaela Mitolo,Francesca Meneghello

doi:10.3389/fnagi.2018.00360

Abstract

Objectives: The aims of the current study are to (1) report the frequency of specific sleep disturbance symptoms in Mild Cognitive Impairment (MCI) and cognitive healthy older persons; (2) examine whether overall poor sleep and specific sleep disturbance symptoms are more common in persons with MCI compared to cognitive healthy older controls and; (3) examine the association between sleep disturbances and performance in general and specific cognitive domains in persons with MCI and separately in cognitive healthy older persons.Methods: Data were collected at the Fondazione Ospedale San Camillo Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Venice, Italy as part of the European VPH-DARE@IT project. We included 69 persons with MCI (mean age 75.7; SD = 7.7) and 72 sex-matched cognitively healthy controls (mean age 71.8; SD = 7.0). Participants underwent extensive neuropsychological assessment and evaluation of subjective sleep performance with the Sleep Continuity in Alzheimer’s Disease Scale(SCADS).Results: A fifth of MCI patients (21.7%, n = 15) had poor sleep compared to 15.3% (n = 11) of cognitively healthy controls. MCI patients had a 3.2 higher odds of having poor sleep compared to cognitively healthy controls after adjustment for age, education, sex, and general cognitive functioning (Odds Ratio (OR) = 3.2; 95% Confidence Interval (CI) = 1.1–9.2). Persons who reported waking up twice or more during the night had higher odds of being MCI compared to those who never wake or wake only once (OR = 2.6; 95% CI = 1.1–6.1). In MCI patients, poor sleep was associated with better general cognitive functioning and short-term working memory, whereas in cognitive healthy older persons poor sleep was associated with impairment in episodic memory performance and executive functioning.Discussion: Our results confirm previous studies showing that sleep disturbances are common in MCI, and this may be due to an ongoing neurodegenerative process rather than a symptom of cognitive impairment. Future research with objective sleep measurements are needed in MCI as well as interventions to improve sleep with the aim of preventing cognitive decline.

Highlights

Sleep health covers a variety of dimensions, with many different definitions in the literature that generally cover a range of aspects including sleep satisfaction, timing, efficiency, and duration (Buysse, 2014)
The characteristics of the study population are shown in Table 1; results are shown for the whole population, and stratified according to Mild Cognitive Impairment (MCI)/control status
A fifth of MCI patients (21.7%, n = 15) had poor sleep compared to 15.3% (n = 11) of cognitively healthy controls

Summary

Introduction

Sleep health covers a variety of dimensions, with many different definitions in the literature that generally cover a range of aspects including sleep satisfaction, timing, efficiency, and duration (Buysse, 2014). Research has shown that poor sleep is related to poorer general cognitive functioning as well as impairment in specific cognitive domains (Gadie et al, 2017). A meta-analysis concluded that persons with symptoms of insomnia show impairment in cognitive functioning in episodic memory, working memory and executive functioning (FortierBrochu et al, 2012). Research suggests that a cumulative index of sleep problems, rather than specific symptoms of poor sleep, is the biggest risk factor for poorer cognitive performance (Gadie et al, 2017). Evidence is conflicting, with some studies reporting no association between sleep disturbance and cognition (Mecca et al, 2018), and some even reporting slightly better cognitive functioning in those with sleep problems (Kyle et al, 2017)

Objectives

Methods

Results

Conclusion