an apparatus is provided for treating obstructive sleep apnea . the apparatus has an external device containing a breathing sensor to sense activity associated with breathing of a subject , and also containing a control unit , coupled to the breathing sensor , for generating a signal in response to anatomical activity associated with breathing . the apparatus also has a sublingual implant , containing a receiver , electrodes and circuitry , which wirelessly receives a signal from the external device and applies current to a sublingual muscle site in response to the signal , in a plurality of successive periods of inspiration , even in the absence of a detection of apnea by the external device .