The feasibility of sleep assessment by actigraph in patients with tetraplegia

Background: Sleep disturbances are frequent in patients with high spinal cord lesions, and are difficult to diagnose by means of polysomnography (PSG). Design: Retrospective cohort study. Objective: Examine the feasibility of sleep assessment by actigraph in patients with tetraplegia. Setting: A rehabilitation center in Israel. Subjects: Twenty-one patients with tetraplegia and 20 healthy persons. Interventions: Sleep assessment by actigraphs attached to the head and the wrist. Main outcome measures: The actigraphic movement index (MI), total sleep time (TST), sleep efficiency (SE), wake after sleep onset (WASO), sleep latency (SL), and number of awakenings (NOA). Results: In the control group actigraphy showed that during sleep the hand moves more than the head but that the movements were highly correlated. In patients with tetraplegia below C ₅-C₇ the hand also moved more than the head, but in patients with tetraplegia below C₄, the head moved more (P<0.05). No significant differences were found between patients with C₅-C ₇ tetraplegia and healthy controls in the sleep indices obtained by hand movements, or between patients with C₄ tetraplegia and healthy controls in the indices obtained by head movements. Control subjects and patients showed similar subjective assessment of sleep quality. Conclusions: These preliminary findings support the validity of wrist actigraphy for sleep assessment in patients with C₅-C₇ tetraplegia, and suggest that head-mounted actigraphy is a feasible alternative for sleep assessment in patients with tetraplegia below C₄. To establish these findings, further investigations are required, with a larger number of patients and comparison with PSG.