Described herein are methods of detecting the presence or progression of neuromuscular disorders (including ALS) based at least in part on diaphragm EMG signals taken at different points in time from the same implanted electrode(s). Signals may be used to diagnose or to monitor progression of a disorder or to track a treatment. Thus, diaphragm EMG signal may be used as a marker (e.g., a 'biomarker') for the detection or progression of a neurological disorder such as ALS. The characteristics or parameters of diaphragm EMG signals may be used to create an activity index, which may be output or compared and further analyzed. These signals may also be analyzed to show a difference between the left and right sides of the diaphragm.
DEVICES AND METHODS FOR ASSESSING MOTOR POINT ELECTROMYOGRAM AS A BIOMARKER