Apnea is defined as a cessation of air flow at the level of the nostrils and mouth lasting at least ten seconds. Hypersomnia Sleep Apnea (HSA) is diagnosed if during a seven hour period of sleep 30 or more such episodes occur predominantly in Non-Rapid Eye Movement (NREM) sleep. In obstructive sleep apnea, respiratory effort continues but there is no air exchange for ten or more seconds. Such patients are frequently obese, complain of excessive daytime sleepiness, snore excessively, suffer from hypertension, morning headache and confusion. If untreated the chronic aleveolar hypoventilation may be followed by symptoms of right heart overload or failure and secondary polycythemia. Treatment has focused around weight loss, drug trials and surgery, most often tracheostomy. Of these, only surgery has given immediate relief and has become the standard treatment. It is the aim of their study to test the effectiveness of a mechanical device which captures the tongue and holds it forward by suction, thus opening the upper airway in reducing the number of apneic episodes during sleep and in improving alertness during waking in patients diagnosed as having primarily obstructive sleep apnea. The results of wearing the Tongue Retaining Device on the Apnea Index (number of apneas per hour of sleep) will be compared for ten severe cases to the results for ten persons following tracheostomy reported by Weitzman. The results for ten mild HSA patients using the TRD will be compared to those of ten patients treated by methods other than surgery. Physiological, psychological and social criteria will be employed as dependent measures.