Association of Self-Perceived Fatigue, Muscle Fatigue, and Sleep Disorders with Cognitive Function in Older Adults: A...

Fatigue and sleep disorders are common geriatric conditions and are associated with an increased risk of cognitive decline. This study aimed to examine the relationships among self-perceived fatigue, objective muscle fatigue, sleep apnea risk, insomnia, and cognitive function, focusing on their associations with mild cognitive impairment (MCI).

Cross-sectional study.

The study involved 217 older adults (median age: 80 years, 65.6% women) from 2 residential care facilities in Vienna, Austria.

Cognitive function was assessed with the Mini-Mental State Examination. Sleep quality and disturbances were evaluated using the Athens Insomnia Scale (AIS) and STOP-BANG questionnaire. Subjective fatigue was measured with the Multidimensional Fatigue Inventory, and objective muscle fatigue through 2 rounds of 10 maximal handgrip strength tests, separated by a 1-hour rest. Multivariable regression models adjusted for age, sex, comorbidities, sleep medication, and total number of medications were used to analyze associations among fatigue, sleep disturbance, and MCI.

Participants with MCI (n = 72) had significantly lower handgrip strength (median Fmax1: 18.75 kg vs 23.44 kg), higher muscle fatigue ratios (median: 1.40 vs 1.19), and poorer recovery ratios (median: 0.85 vs 1.01) compared with those without MCI (n = 145). Sleep disorders and fatigue measures were more common in those with MCI, with 80.6% reporting insomnia (AIS ≥6) compared with 21.4% in the cognitively intact group. Logistic regression showed that muscle fatigue combined with sleep apnea risk was associated with the highest odds of cognitive impairment [odds ratio (OR), 6.12; 95% CI, 2.77-13.51; adjusted OR, 3.02; 95% CI, 1.15-7.92]. Recovery capacity showed a positive association with cognitive function (β = 0.150, P < .05).

Sleep apnea, muscle fatigue, and reduced recovery capacity are significantly associated with cognitive decline in older adults. Assessing these factors may help in identifying individuals at risk of cognitive impairment.