The Impact of Missing Data and Imputation Methods on the Analysis of 24-Hour Activity Patterns.

The purpose of this study is to characterize the impact of the timing and duration of missing actigraphy data on interdaily stability (IS) and intradaily variability (IV) calculation. The performance of three missing data imputation methods (linear interpolation, mean time of day (ToD), and median ToD imputation) for estimating IV and IS was also tested. Week-long actigraphy records with no non-wear or missing timeseries data were masked with zeros or 'Not a Number' (NaN) across a range of timings and durations for single and multiple missing data bouts.

Objective underpinnings of self-reported sleep quality in middle-aged and older adults: The importance of N2 and wakefulness.

Study Objectives: The measurable aspects of brain function (polysomnography, PSG) that are correlated with sleep satisfaction are poorly understood. Using recent developments in automated sleep scoring, which remove the within- and between-rater error associated with human scoring, we examine whether PSG measures are associated with sleep satisfaction.

Design And Setting: A single night of PSG data was compared to contemporaneously collected measures of sleep satisfaction with Random Forest regressions.