Descriptive physiological data on a sleep bruxism population.

We studied 24 bruxers (23-67 years old). They often complained of orofacial and bodily pain and presented autonomic symptoms (sweating 23%, palpitations at night 62%, decreased libido 50%); 19% had increased blood pressure requiring treatment, and 65% reported frequent headaches in the morning. Deep sleep and rapid eye movement (REM) were delayed. An average of 167 orofacial episodes developed during the night. The mean number of masseter bursts strictly defined as bruxism was 79, the mean delay for the first occurrence after sleep onset 18 minutes. The majority of bruxism occurred in stage 2 sleep and REM sleep. The mean number of shifts of sleep stages was 70, one-third occurring within the first minute following a bruxing episode, and 15% of bruxing episodes developed after a shift in sleep stage. Electroencephalogram showed alpha-delta pattern in 15% of the subjects. Short-lasting alpha activity was often encountered during the 10 seconds preceding the development of a bruxing episode. Tachycardia developed at its onset, persisting for 10 seconds. We suggest that, as a minor alarm response to endogenous/exogenous stimuli, arousal develops and is often followed by motor activation, such as a burst of bruxing, with, as in any situation when motor activity suddenly increases, a secondary increase of heart activity.