Actigraphy combined with EEG compared to polysomnography in sleep apnea patients

An actigraph extended with electroencephalography (EEG), electroocculography (EOG) and electromyography (EMG) was compared to polysomnography in two studies on patients suffering from sleep disordered breathing. Study A with 30 subjects used a single lead EEG, and study B with 20 subjects used EOG and EMG in addition. Sleep was scored according to Rechtschaffen and Kales rules. Total sleep time (TST), sleep period time (SPT), sleep efficiency (SE), sustained sleep efficiency (SSE), sleep-onset latency (SL), and sleep stages were compared. For study A an epoch-by-epoch comparison of sleep stages revealed an overall agreement of 74.2%. Correlations were high for SE (0.98, p < 0.001), SSE (0.98, p < 0.001), TST (0.99, p < 0.001), SPT (0.99, p < 0.001), and SL (0.98, p < 0.001). Regarding the sleep stages, correlations were high for rapid eye movement (REM) (0.83, p < 0.001), light-sleep (0.78, p < 0.001), and deep sleep (0.73, p < 0.001). For study B, results of an epoch-by-epoch comparison of sleep stages showed an overall agreement of 75.5%. Correlations were high for SE (0.98, p < 0.001), SSE (0.98, p < 0.001), TST (0.87, p < 0.001), SL (0.98, p < 0.001), SPT (0.94, p < 0.001), and for rapid eye movement (REM) (0.91, p < 0.001), light-sleep (0.74, p < 0.001), and deep sleep (0.89, p < 0.001). In summary the study revealed high agreement between polysomnography and single lead EEG in sleep apnea patients. Deviations for REM were slightly higher for the single lead EEG compared to single lead EEG plus EOG/EMG. Both simplified systems proved to be reliable for comfortable out-patient sleep recording.