EEG and ECG Characteristics of Human Sleep Composition Types

Unsupervised clustering of staged human polysomnographic recordings reveals a hierarchy of sleep composition types described primarily by sleep efficiency and slow wave sleep content. Associations are found between these sleep clusters and health-related variables including BMI, smoking habits, and heart disease, showing that sleep types correspond to objective and medically relevant groupings. The present work describes the sleep type hierarchy, and studies the EEG and ECG correlates of sleep composition type. It is found that measures of EEG variation such as δ, θ, and α spectral content, as well as average heart rate, and measures of heart rate variability, including the standard deviation of the sequence of RR intervals, and Hjörth activity and mobility of the ECG signal, differ significantly among sleep composition type clusters. EEG analysis is shown to allow approximate reconstruction of sleep type without the need for ECG data, while ECG alone is found to be insufficient for accurate sleep type classification.