Actigraphic, but not subjective, sleep measures are associated with cognitive impairment in memory clinic patients

Abstract

Aim Sleep disturbances are prevalent in various dementia subtypes but rarely investigated in early clinical stages. Although memory clinics have become an established institution for the early diagnosis of dementia, sleep assessment is not part of their routine diagnostics. This study aimed to examine whether subjective and objective sleep variables are related to cognitive impairment in patients referred to a memory clinic. Methods On two consecutive days, patients underwent routine diagnostic procedures, including a neuropsychological examination (consortium to establish a registry for alzheimer's disease), and had their sleep quality evaluated by the Pittsburgh Sleep Quality Index and overnight hand‐wrist actigraphy. Results Data of 31 patients (age, M ± SEM: 74.1 ± 1.5; 18 women, 13 men; Clinical Dementia Rating: 0–1) were analysed. One had been diagnosed with subjective cognitive impairment, 13 with mild cognitive impairment with or without depression, and 17 with dementia syndrome due to Alzheimer's and/or cerebrovascular disease. Compared to patients with subjective or mild cognitive impairment, dementia patients showed a significantly increased nocturnal acceleration magnitude; other differences in subjective and objective sleep measures were not significant. Comparing patients with subjectively poor (Pittsburgh Sleep Quality Index > 5: n = 9) and good sleep (Pittsburgh Sleep Quality Index ≤ 5: n = 22) yielded no differences in any neuropsychological and clinical variables. In contrast, patients with low actigraphically recorded sleep efficiency (<85%: n = 11) exhibited a significantly more impaired cognitive performance than those in the high sleep efficiency group (≥85%: n = 20). Correlation analyses demonstrated that actigraphically assessed disturbed sleep continuity accompanied by increased night‐time motor activity was substantially associated with cognitive impairment. Conclusion This study highlights that objectively assessed, but not self‐reported, parameters of disturbed sleep are closely related to cognitive dysfunction in the early stages of dementia of different aetiologies. Possible diagnostic and treatment implications are discussed.

Sleep actigraphic patterns and cognitive status

“…Actigraphy seems to be a promising diagnostic approach for a fast, sim-ple and widely available possibility to investigate and objectively detect sleep disorders, especially in the early stage of cognitive impairment. In agreement with our findings, the results of a recent survey of patients referred to a memory clinic showed that objective data supported by actigraphy are more reliable than self-reported information for assessing correlations between sleep disturbances and cognitive dysfunction [37]. Polysomnography remains the gold standard approach for definitive and accurate characterization of the sleep profile.…”

Objective and subjective sleep measures are associated with neurocognition in aging adults with and without HIV

“…The association between sleep and learning is consistent with the Mahmood et al ( 2018) study, which found poor subjective sleep quality was associated with learning in a somewhat younger group of PWH. Additionally, studies in older adult samples have found that objectively-measured efficiency and fragmentation, but not the subjective PSQI score, are associated with worse learning and memory (Cabanel et al, 2020;Cavuoto et al, 2016). The aging literature also suggests that long total sleep time may be worse for cognition than short total sleep time (Devore et al, 2016); however, our study had only one person with longer sleep time (i.e., >9 h), so long versus short sleep time could not be evaluated.…”

Sensory-Evoked 40-Hz Gamma Oscillation Improves Sleep and Daily Living Activities in Alzheimer’s Disease Patients

“…Although actigraphy can detect rest and active periods, cross-validation with polysomnography sleep studies has led to the generally accepted interpretation that periods of nighttime restfulness are considered a reasonable measure of sleep (Tachikawa et al, 2017;Smith et al, 2018). Furthermore, previous studies have demonstrated that for AD patients, assessment of sleep by actigraphy is more accurate and reliable than a subjective report of sleep quality due to the ease of use, passive effort, and continuous measurement (Canazei et al, 2019) and has been more directly linked to cognitive impairment (Cabanel et al, 2020). In line with these observations, recent experimental and epidemiological findings demonstrate that sleep disorders represent a risk for developing AD, and a close correlation exists between sleep abnormalities and decline in activities of daily living of AD patients (Macedo et al, 2017;Hennawy et al, 2019;Bubu et al, 2020).…”