Methods and systems for evaluating a pathological condition include acquiring movement information, such as electromyogram (EMG) information, and sleep disordered breathing (SDB) information, and detecting the presence of a pathological condition using both movement and SDB information. Methods may involve sensing physiological signals including at least muscle movement signals. Sleep-related disorders are detected using the sensed physiological signals, the sleep-related disorders including at least an involuntary muscle movement disorder and sleep-disordered breathing. Methods and systems also provide for detecting and treating a sleep-related disorder using movement and SDB information. Cardiac, respiratory, nerve stimulation, drug, or a combination of such therapies may be delivered to treat a detected or diagnosed pathological condition.