This document discusses, among other things, a system and method for optimizing a sleep therapy using a closed loop neuromodulator. A first sleep disorder event can be detected using first activity information, and a first stimulus can be provided, in response to the first sleep disorder event, using a set of stimulus parameters. Termination of the first sleep disorder event can be detected using second activity information, and at least one therapy parameter can be adjusted to decrease an energy level of a subsequent stimulus.