MOTOR-ACTIVITY IN SLEEP BRUXISM WITH CONCOMITANT JAW MUSCLE PAIN - A RETROSPECTIVE PILOT-STUDY

In a controlled polysomnographic (PSG) study that we recently performe d in our laboratory, we noticed that some patients with a chief compla int of sleep bruxism reported concomitant non-myofascial pain in their masticatory muscles. To study the influence of such pain on the patte rn of bruxism motor activity, we re-assessed the 2nd out of 2 consecut ive PSG and masseter electromyographic (EMG) recordings of 7 bruxers w ithout pain and 6 bruxers with concomitant jaw muscle pain. Among othe rs, the selection of these patients was based on reports of current ja w muscle pain intensity, using 100-mm visual analogue scales. In our s ample of bruxism patients with pain, levels of pain intensity did not differ significantly between bedtime and awakening in the morning. Alt hough there were no significant differences between both subgroups of bruxers in the number of bruxism bursts per episode and the root-mean- squared EMG level per bruxism burst, bruxers with pain had 40% less br uxism episodes per hour of sleep. This suggests that non-myofascial ja w muscle pain decreases the number of initiations of bruxism episodes, but leaves their contents unaffected.