Association Between Sleep Characteristics and Mild Cognitive Impairment in Elderly People

Abstract

We compared the sleep quality indices between patients with mild cognitive impairment (MCI) and normal elderly subjects and analyzed the effects of sleep characteristics on cognitive functions. Cases of MCI patients (320 persons, MCI group) and 630 normal elderly with matched age, gender, and level of education (control group) were enrolled in this study. The Pittsburgh Sleep Quality Index (PSQI) was used to assess the sleep characteristics. The Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) were used to assess cognitive function. There were 110 (34.3%) and 170 (27%) cases with sleep disorders in the MCI and control groups, respectively (P < 0.01). There was a significant difference of total PQSI scores between the two groups, and the scores of sleep duration (factor III) and habitual sleep efficiency (factor IV) in the MCI group were significantly lower than those in the control group. Total PQSI scores negatively correlated with MoCA scores and MMSE scores. MoCA scores negatively correlated with scores of the sleep latency (factor II), sleep duration (factor III), and habitual sleep efficiency (factor IV), while MMSE scores negatively correlated with scores of factor III and factor IV. The scores of attention and calculation, reading and language understanding, and visuospatial function (MMSE), and also of visuospatial/executive function, attention, and clock-drawing test (MoCA) in MCI patients without sleep disorders were significantly higher than those in MCI patients with such disorders. The incidence of sleep disorders is higher in patients with MCI, compared with normal elderly. Effects of sleep disorders on cognitive functions are mainly reflected in the state of attention, and visuospatial/executive function.

Sleep quality features and their association with mood symptoms and cognitive factors in a non‐clinical sample of older Brazilian adults

“…As expected, poor sleep quality was linked with deficits in cognition, which previous studies have likewise found . These deficits are reflected mainly in low reading and language comprehension and an impaired attention span …”

“…22 These deficits are reflected mainly in low reading and language comprehension and an impaired attention span. 23 In this sample, the most common factors in the sleep disturbance component were 'Wake up in the middle of the night or early morning' and 'Have to get up to use the bathroom'. These results are not surprising: older adults may develop an increased risk of insomnia with advancing age, and the presence of nocturia can affect night-time sleep.…”

Prevalence and correlates of sleep problems among elderly Singaporeans

“…4 This effect of sleep on cognition was evident even when comparing individuals with mild cognitive impairment (MCI) with sleep disorders to MCI patients without sleep disorders, whereby the latter had significantly higher scores in domains such as attention, visuo-spatial/executive function compared to the former. 27 One possible reason for the insignificant finding in this study might be due to the limited number of cognitive domains that were examined in relation to sleep problems. Past studies, such as that by Blackwell et al, 28 have found sleep disruptions at different sleep stages to be associated with deficits in various cognitive domains, particularly executive functioning.…”

“…found 24% of good sleepers to have cognitive deficits compared to 52% of poor sleepers on the Mini‐Mental State Examination . This effect of sleep on cognition was evident even when comparing individuals with mild cognitive impairment (MCI) with sleep disorders to MCI patients without sleep disorders, whereby the latter had significantly higher scores in domains such as attention, visuo‐spatial/executive function compared to the former …”

Sleep Disturbance in Older Adults With or Without Mild Cognitive Impairment and Its Associated Factors Residing in Rural Area, China

“…Sample size calculations were performed using PASS 15.0 24 for Testing Two Proportions using the Z-Test. Based on a previous study which reported 34.3% and 27% of cases with sleep disturbance in the MCI and normal cognition groups, 25 the power and type 1 error probability were set at 0.80 and 0.05, respectively. Under these assumptions, a minimum of 1,246 participants were needed to evaluate the prevalence of sleep disturbance among mild cognitively impaired and noncognitively impaired older adults.…”