Assessment of sleep parameters during contingent electrical stimulation in subjects with jaw muscle activity during sleep: a polysomnographic study

There is emerging evidence that feedback techniques based on contingent electrical stimulation (CES) have an inhibitory effect on the electromyogram (EMG) activity of jaw-closing muscles and therefore could be useful in the management of sleep bruxism. This polysomnographic (PSG) study was designed to investigate the effect of CES on PSG parameters in subjects with self-reported bruxism. Fourteen subjects underwent a full PSG investigation in the laboratory for three consecutive nights - one night of adaptation, one night without CES, and one night with CES - in a randomized order. During all sessions the EMG activity was recorded by a portable feedback device from the temporalis muscle. An electrical pulse, which was adjusted to a moderate, but non-painful, intensity, was applied to subjects during the session with CES, if jaw-muscle activity was detected. The total sleep time, the number of micro-arousals per hour of sleep, the time spent in sleep stages 3 and 4 and in rapid eye movement (REM) sleep, and the number of periodic limb movements, were not influenced by CES. The number of EMG episodes per hour of sleep during the nights with and without CES was not significantly different. The present study suggests that CES at non-painful intensities does not cause major arousal responses in any of the sleep parameters assessed in this study.