Contingent electrical lip stimulation for sleep bruxism: A pilot study

Statement of problem. No effective method has been found to fully control sleep bruxism, although contingent feedback methods show some promise. Purpose. This demonstration-of-concept study evaluated the effect of contingent electrical lip stimulation on sleep bruxism. Material and methods. Recordings of masseter muscle activity were performed over 5 nights in 7 subjects with acknowledged bruxism and dental attrition (5 men, 2 women). A small electrical switch, activated with light force clenching, was mounted between 2 occlusal orthotics. This switch triggered a stimulator, which delivered slightly noxious electrical pulses to the subject's lip. After a baseline first night recording session, stimulation was delivered in 1-hour blocks for half of each sleep period during nights 2 through 5. Paired t tests (alpha = 0.05) were conducted on 4 recorded bruxism parameters. Results. With stimulation, the number (+/-SD) of events/hour reduced from a baseline level of 3.9 +/- 2.0 to 2.4 +/- 0.8 and the mean amplitude (% maximum voluntary contraction) reduced from 28.7 +/- 20.0 to 17.6 +/- 4.1. There was a mean decrease in the duration (s/event) from 10.6 +/- 1.4 to 9.1 +/- 2.5 and the total event time (s/hour) was reduced from 41.7 +/- 22.4 to 23.2 +/- 11.0. Among these measures, bruxism events with and without stimulation were compared, and only the duration of individual bruxism events (s/event) showed a significant change (P=.038). Finally, no subject reported being awakened from sleep by the stimulation. Conclusion. The reductions in bruxism events were noteworthy, especially considering that stimulation was delivered for only half of the sleeping period.