title: Effect of contingent electrical stimulation on jaw muscle activity during sleep: a pilot study with a randomized controlled trial design.
abstract: OBJECTIVE
  To determine the effect of contingent electrical stimulation (CES) on jaw muscle activity during sleep in a double-blinded randomized controlled trial (RCT).
  
  
  METHODS
  Eleven patients with myofascial TMD (mean age 37 years) and with a clinical diagnosis of bruxism were included. EMG activity (Grindcare®) was recorded from the anterior temporalis muscle during sleep and analyzed online. Jaw muscle activity related to clenching or grinding triggered an electrical square-wave pulse train (450 ms) adjusted to a clear, but non-painful intensity. TMD patients were randomized into two groups: active treatment with CES or no CES (placebo). Number of EMG episodes/hour sleep was the primary outcome parameter. The following variables were assessed as secondary outcome parameters; number of painful muscles, maximum pain-free jaw opening, characteristic pain intensity, depression scores and Oral Health Impact Profile scores. Numerical Rating Scale scores for self-reported pain and muscle tension were registered for at least 4 nights per week during the experiment.
  
  
  RESULTS
  The number of EMG episodes/hour sleep was significantly reduced (52 ± 12%) in the CES group during the sessions with CES (ANOVA: p = 0.021) compared to baseline. There were no significant differences in the secondary outcome parameters (ANOVA: p > 0.513) or pain or muscle tension scores between groups (p = 0.645). The average duration of sleep hours during the nights with and without CES was not significantly different (p = 0.646).
  
  
  CONCLUSIONS
  These results demonstrate a significant inhibitory effect of CES on jaw muscle EMG activity during sleep in a RCT, but with no effects on self-reported pain.
authors.affiliation: Section of Clinical Oral Physiology, Department of Dentistry, HEALTH, Aarhus University, Denmark.
authors.forename: Faramarz
authors.initials: F
authors.lastname: Jadidi
authors.forename: Eduardo E
authors.initials: EE
authors.lastname: Castrillon
authors.forename: Patricia
authors.initials: P
authors.lastname: Nielsen
authors.forename: Lene
authors.initials: L
authors.lastname: Baad-Hansen
authors.forename: Peter
authors.initials: P
authors.lastname: Svensson
mesh_terms: D000328:Adult; D004558:Electric Stimulation; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008406:Masseter Muscle / Q000502:physiology*; D010865:Pilot Projects; D012890:Sleep / Q000502:physiology*