The respiration rate of a patient may be measured by sensing respiration motion using two MEMS devices, and by processing a respiration signal produced by processing the outputs of the two MEMS devices. Some embodiments dispose two accelerometers around a patients abdomen and determine respiratory motion from the difference between the outputs of the two accelerometers. Other embodiments dispose two non-identical accelerometers at substantially the same location on the patients body, such that each of the accelerometers is exposed to the same respiratory motion, and determine respiratory motion from the difference between the outputs of the two accelerometers.
