Abstract: A fall detector unit is worn by a patient and performs a wakeup when an acceleration signal exceeds a predetermined threshold. A barometer provides a series of pressure readings over a pressure examination period to provide a first pressure difference value. The pressure signals are further monitored over a compensation period after the examination period to obtain a second pressure difference value representing background environmental changes. The first pressure difference value is compensated by the second pressure difference value to obtain a total pressure difference value and thus derive a total height difference value. The fall detector unit determines a fall event using the total height difference value.