The invention provides a system suitable for monitoring the usage of a toothbrush, the system comprising: (a) a toothbrush； (b) a sound sensor which is located in or on the toothbrush； (c) a programmable data logger which is located in or on the toothbrush, the data logger incorporating a motion sensor and a data store for the logging of data； (d) switching means for triggering the operation of the sound sensor in response to initial signals of toothbrush motion generated by the motion sensor, and (e) a data analysis device which is adapted to analyse data transmitted or acquired from the system to provide information about tooth brushing behaviour； in which the duration of data logging is controllable in response to the combined signals received from the sound sensor and the motion sensor respectively.
