SLEEP STAGING USING AN IN-EAR PHOTOPLETHYSMOGRAPHY (PPG)

Aspects of the present disclosure provide methods and apparatuses for determining a subject's sleep stage based on a PPG signal measured using an in-ear earpiece, In aspects, one or more physiological signals are estimated based on the PPG. Based, at least in part, on the determined sleep stage, one or more outputs are provided. In an example, the outputs are provided to the subject, the subject's physician, the subject's clinician, the cloud, and/or a device external to the apparatus. The methods and apparatus of determining the subject's sleep state described herein are continuous and non-invasive and eliminate the need for a clinical setting.