Abstract: Apparatus for detecting breathing disorders in a person, comprising a sensor constructed to be located on, in, or under a mattress to sense mechanical vibrations of a body part of the person while lying on the mattress, and a control system designed to receive the output of the sensor, and to perform the following operations: filter out the breath components of the sensor output; sample the breath components during predetermined short time durations (NS); determine the average energy ES in the samples; sample breath components during long time durations (NL); determine the average energy (EL) in the latter samples; calculate a breath quality factor (BQF) by dividing ES by EL (ES/EL); and actuating a display, alarm, and/or control when the BQF is a predetermined value less than 1.0.