Females with sleep bruxism show lower theta and alpha electroencephalographic activity irrespective of transient morning masticatory muscle pain

J Orofac Pain. Spring 2013;27(2):123-34. doi: 10.11607/jop.999.


Aims: To investigate the hypothesis that the presence of transient morning masticatory muscle pain in young, healthy sleep bruxers (SBr) is associated with sex-related differences in sleep electroencephalographic (EEG) activity.

Methods: Data on morning masticatory muscle pain and sleep variables were obtained from visual analog scales and a second night of polysomnographic recordings. Nineteen normal control (CTRL) subjects were age- and sex-matched to 62 tooth-grinding SBr. Differences in sleep macrostructure (stage distribution and duration, number of sleep-stage shifts), number of rhythmic masticatory muscle activity (RMMA) events÷ hour, and EEG activity were analyzed blind to subject status. The influence of pain and gender in SBr and CTRL subjects was assessed with the Fisher's exact test, Mann-Whitney U test, two-sample t test, and analysis of variance (ANOVA).

Results: Low-intensity morning transient orofacial pain was reported by 71% of SBr, with no sex difference. RMMA event frequency was higher in SB than CTRL subjects (4.5÷hour vs 1.3÷hour; P < .001). SBr had fewer sleep-stage shifts, irrespective of sex or pain status. Female SBr had significantly lower theta and alpha EEG activity compared to female CTRL subjects (P = .03), irrespective of pain.

Conclusion: Female SBr had lower theta and alpha EEG activity irrespective of transient morning pain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Analysis of Variance
  • Arousal
  • Case-Control Studies
  • Chi-Square Distribution
  • Circadian Rhythm
  • Electroencephalography
  • Facial Pain / etiology*
  • Female
  • Humans
  • Male
  • Masticatory Muscles / physiopathology*
  • Pain Measurement
  • Polysomnography
  • Sex Factors
  • Sleep Bruxism / complications*
  • Sleep Bruxism / physiopathology*
  • Sleep Stages
  • Statistics, Nonparametric
  • Young Adult