Patients with severe obstructive sleep apnea polygraphically documented underwent electrical stimulation treatment trials. Submental and intraoral stimulations were applied during waking and during nocturnal sleep. The stimulation was applied using a custom-designed neuromuscular electrical stimulator (EdenTec Corp) providing symmetric biphasic constant voltage pulses. Pulse duration of each phase was set to 80 microseconds based on a subjective evaluation of pulse durations from 80 to 300 microseconds to minimize sensation while generating equivalent motor responses. Pulse repetition rate was set to 50 pulses per second. Cephalometric radiographs and endoscopies were obtained with and without stimulations during waking. Most commonly, stimulations induced alpha EEG arousals. Submental subcutaneous stimulation induced good contractions of platysmal muscles but had no impact on the upper airway. Intraoral stimulation induced clear tongue muscle movements but with change of shape of the upper airway and posterior movements of the tongue. Each time a breakage of apnea was noted, it was associated with a time-linked alpha EEG arousal. The results obtained by us and others do not, at this time, give convincing support for the use of electrical stimulation using submental surface or intraoral electrodes as a viable approach for effective control of obstructive sleep apnea syndrome symptoms.