This invention is a fully implanted functional electrical stimulator (20) apparatus, a method for treatment of obstructive sleep apnea that provides for both reliable detection/prediction or airway occlusion that relieves, and/or prevents same by selective, direct electrical stimulation of the hypoglossal nerve (HG). The method, and apparatus sense hypoglossal nerve electro-neurogram activity for purposes of detecting or predicting obstructive sleep apnea. The sensed hypoglossal nerve activity, itself, is used to trigger functional electrical stimulation of the hypoglossal nerve in order to improve upper airway patency. Further, an improved hypoglossal nerve stimulation electrode (10) interface (IC) is provided that allows for simultaneous hypoglossal nerve activity sensing, and stimulation by eliminating stimulation artifacts that would otherwise trigger further erroneous stimulation.