Ecological momentary assessment of sleep, symptoms, and mood during chemotherapy for breast cancer.

OBJECTIVE: This study examined the association of sleep before and during a chemotherapy (CT) cycle for breast cancer with symptoms and mood during a CT cycle.
METHODS: Twenty women undergoing CT for breast cancer completed the Pittsburgh Sleep Quality Index (PSQI) 1 h prior to a CT infusion. For 3 weeks following infusion, participants estimated sleep efficiency, minutes to sleep (sleep latency), number of nocturnal awakenings (sleep fragmentation (SF)), and sleep quality (SQ) each morning and rated symptoms (nausea, fatigue, numbness, and difficulty thinking) and mood three times daily (morning, afternoon, and evening) via ecological momentary assessments using automated handheld computers.
RESULTS: The results showed that disturbed sleep (PSQI score > 5) prior to CT infusion was associated with greater fatigue, and more negative and anxious mood throughout the 3-week CT cycle, and good pre-CT infusion sleep (PSQI score < 5) buffered anxious mood in the first days following infusion. Time-lagged analyses controlling for mood/symptom ratings reported the previous evening revealed that longer sleep latency and greater SF were associated with greater daytime fatigue; poorer SQ and greater SF were antecedents of worse morning negative mood, and greater SF was associated with feeling more passive and drowsy. No evening symptom or mood ratings were related to subsequent SQ.
CONCLUSIONS: These findings suggest that disturbed sleep before and after a CT infusion exacerbates fatigue, and negative, anxious, and drowsy mood during a CT cycle. Reducing sleep disturbance may be an important way to improve quality of life during CT.