A comparison of Holter and polysomnogram-based detection of bed and wake times

To determine if bed and wake times can be determined from continuous ECG recordings in the elderly, PSG (polysomnogram), ECG channels were extracted and scanned on a Holter analyzer for N=56 participants (age 76plusmn3) in the Sleep Heart Health Study who had 2 PSGs 5 years apart. Bed and wake times were determined from a combination of 5-min averaged HR and HRV patterns and from HR tachograms of normal-to-normal intervals. Bed and wake times were also extracted from the PSGs. PSG- and HRV bed and wake times were compared via paired t-tests and correlation analysis. Correlations between PSG- and HRV-determined bed and wake times were les0.95. HRV-derived bed and wake times were slightly (4plusmn7 min) earlier for and 5plusmn11 min earlier the 2 PSGs, ples0.001. Mean PSG and ECG-based wake times were closer (12plusmn20s earlier, p=0.069 and 2plusmn8 min later, p=0.049 for the 2 PSGs). Therefore, determination of bedtime and wake time patterns in large Holter cohorts without activity diaries is feasible.