In a personal emergency response system (PERS), a personal help button (PHB) (10) includes a call button (12), a motion sensor (22), and a transmitter or transceiver (24) for transmitting a wireless call signal responsive to pressing the call button. An electronic processor (28) performs a compliance monitoring process (42) at successive compliance check times, each including: acquiring motion sensor data over a compliance data acquisition time interval; determining whether the PHB has moved since the last compliance check time; and assessing compliance based at least in part on the determination of whether the PHB has moved. The determining may include determining an orientation change of the PHB since the last check time. Alternatively, compliance may be monitored by detecting and logging wake-up interrupt events that cause the motion sensor to switch from a low-power mode to an operational mode.