A medical device is configured to produce an accelerometer signal and detect a patient fall from the accelerometer signal. The device generates a body posture signal and a body acceleration signal from the accelerometer signal and detects a patient fall in response to determining that the body posture signal and the body acceleration signal meet fall detection criteria. The medical device is configured to receive a truth signal from another device that is not the medical device. The truth signal may indicate that the detected patient fall is a falsely detected patient fall and, responsive to receiving the truth signal, the medical device adjusts at least one fall detection control parameter.