An example of a system for assisting a rescuer in providing CPR includes a motion sensor configured to generate signals indicative of chest motion during CPR chest compressions, and a defibrillator including a display screen configured to provide CPR feedback and defibrillation information and a processor configured to receive the signals, generate a compression waveform based on the signals, detect, in the compression waveform, features characteristic of chest compressions, compare the detected features to a predetermined criterion that distinguishes between manually delivered and compressions delivered by an automated compression device, and selectively provide the CPR feedback based on whether the compressions are the manually delivered or the automated compressions, where the selective provision of the CPR feedback includes displaying CPR parameters for the manually delivered compressions, and a removing from the display screen at least one CPR parameter of the CPR parameters for the automated compressions.