Relationships between self-reported sleep quality components and cognitive functioning in breast cancer survivors up to 10 years following chemotherapy.

OBJECTIVE: Links have been made between aspects of sleep quality and cognitive function in breast cancer survivors (BCS), but findings are heterogeneous. The objective of this study is to examine relationships between specific sleep quality components (latency, duration, efficiency, daytime sleepiness, sleep disturbance, use of sleep aids) and cognitive impairment (performance and perceived), and determine which sleep quality components are the most significant contributors to cognitive impairments in BCS 6 months to 10 years post chemotherapy.

METHODS: Women 21 to 65 years old with a history of non-metastatic breast cancer following chemotherapy completion were recruited. Data collection included surveys to evaluate sleep quality and perceived cognitive impairments, and neuropsychological testing to evaluate verbal fluency and memory. Descriptive statistics, bivariate correlations, and hierarchical multiple regression were calculated.

RESULTS: Ninety women (mean age 49) completed data collection. Moderate significant correlations were found between daytime dysfunction, sleep efficiency, sleep latency, and sleep disturbance and perceived cognitive impairment (Rs = -0.37 to -0.49, Ps < .00049), but not objective cognitive performance of verbal fluency, memory, or attention. After accounting for individual and clinical characteristics, the strongest predictors of perceived cognitive impairments were daytime dysfunction, sleep efficiency, and sleep disturbance.

CONCLUSIONS: Findings support links between sleep quality and perceived cognitive impairments in BCS and suggest specific components of sleep quality (daytime dysfunction, sleep efficiency, and sleep disturbance) are associated with perceived cognitive functioning in this population. Findings can assist clinicians in guiding survivors to manage sleep and cognitive problems and aid in the design of interventional research.