the box 70 can be fully filled when the rescuer is not fully releasing the amount of fill in the release indication box is decreased such that the box is only partially filled e g as shown in box 72 of fig4 b in some examples the depth and rate of cpr chest compressions can be determined based on information collected from an accelerometer while the release of the cpr chest compressions can be based on information collected from a light or capacitive touch sensor for example as shown in fig5 a cpr monitoring device 86 that includes a light sensor or capacitive touch sensor 88 and an accelerometer can be affixed to a victim 39 s chest at a location corresponding to the location of the rescuer 39 s hands when delivering manual chest compressions prior to the administration of cpr the light sensor measures light impinging on the sensor and provides the information to a computing device in the defibrillator the defibrillator processes the information to determine whether the rescuer 39 s hands are in contact with the light sensor 88 more particularly because the device 86 is affixed to the victim 39 s chest or on top of the cpr sensor at a location corresponding to the location of the rescuer 39 s hands when delivering manual chest compressions the presence or absence of light detection by the.