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Understanding the effect of fatigue on the association between sleep disturbances and cognitive function ability among cognitively impaired older adults
Author(s) -
Kerner Nancy,
Cohen Hannah,
Scodes Jennifer,
Bell Sophie,
Goldberg Terry E.,
Westwood Andrew,
Devanand Davangere P.
Publication year - 2020
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1002/alz.040590
Subject(s) - cognition , depression (economics) , sleep (system call) , pittsburgh sleep quality index , geriatric depression scale , sleep disorder , medicine , psychology , clinical psychology , psychiatry , sleep quality , depressive symptoms , macroeconomics , computer science , economics , operating system
Background Fatigue is associated with neuroinflammation of the brain, one of the signatures of neurodegenerative disorders across preclinical and clinical stages. Substantial research evidence demonstrates a bidirectional link between Alzheimer’s neuropathology and poor sleep. Whether neuroinflammation mediates the association between sleep disturbances and cognitive decline remains to be determined. In this pilot study, we examined whether fatigue impacts the relationship between sleep quality and cognitive function ability. Method We prospectively recruited adults aged 55‐90 years with mild cognitive impairment to evaluate their symptoms of Fatigue, Sleep, and Cognitive Function Abilities (CFA), using the NIH PROMIS Fatigue short form (v1.0), Sleep Disturbances (SD, v2.0) and Sleep‐related Impairment short form (SRI v2.0), as well as the NIH Neuro‐QOL Cognitive Function Abilities short form (v1.0). The Poor‐sleep group was defined as a T‐score of >50 on either SD or SRI scale. Depression was defined as a Geriatric Depression Scale score of 5 or greater and was a study exclusion criterion. Result Twenty‐seven patients enrolled in the study, including 14 women and 13 men. The mean age was 67.37+/‐ 9.00 years. The Poor‐sleep group had significantly lower CFA compared to the Good‐sleep group (b=‐6.28, p=0.019). Greater Fatigue scores were significantly associated with lower Cognitive Function Abilities scores (r=.49, p=0.010). These results remained significant after controlling for age. Further, total scale SRI score was significantly associated with total scale Fatigue score (r=.72, p<0.001). Conclusion Both fatigue and sleep disturbances were significantly associated with low CFA independently, along with a significant correlation between fatigue and poor sleep. The mechanisms by which fatigue and sleep disturbances contribute to cognitive test performance need to be elucidated in future research.