 In several studies either direct or indirect stimulation of the musculus genioglossus and its supplying nerves were deployed. Yet, the results were inconsistent. The direct muscle stimulation using intramuscular electrodes, although efficient, was no longer pursued due to technical reasons. Although the results of an external stimulation showed improvements regarding apneas and snoring, the findings were usually weakly pronounced. In a study ascertaining muscle training with transcutaneous electrical stimulation a significant improvement regarding snoring was achieved when compared to placebo. In general, no influence on sleep apnea syndrome could be accomplished, although there were individual cases showing a clinically relevant amelioration. 