TOOTHBRUSH MOTION ANALYSIS

A method of identifying a toothbrush user from among a plurality of different toothbrush users comprises obtaining data indicative of toothbrush motion relative to at least two axes of the toothbrush and filtering the motion data to extract motion data over a predetermined frequency range, such as within a predetermined frequency passband. A motion component distribution of the filtered motion data is determined, and the motion component distribution is compared with a plurality of user-specific motion component distributions to establish the data as indicative of one of said plurality of users. Toothbrushing data captured by a multi-user toothbrush motion tracking system can thereby be ascribed to a correct user within a cohort of users of the system.