title: Association of Masseter Muscle Activities during Awake and Sleep Periods with Self-Reported Anxiety, Depression, and Somatic Symptoms.
abstract: OBJECTIVE
  The objective of this study was to determine if duty factors (DF) of low-magnitude MMA during awake and sleep periods were associated with self-reports of anxiety, depression, and somatic symptoms, and if so, whether or not any associations were modified by gender or the presence of pain. Limited information is currently available in the literature regarding the association of low-magnitude masseter muscle activities (MMA) in habitual environmental settings and the presence of psychological symptoms.
  
  
  METHODS
  Sixty-eight consenting participants were classified using the Diagnostic Criteria for Temporomandibular Disorders examination and validated self-reporting psychological symptom evaluation questionnaires. Each subject also had masseter electromyography recordings during standardized biting tasks in 2 laboratory sessions to calibrate the in-field MMA collected during 3 awake and 3 sleep periods.
  
  
  RESULTS
  During awake periods, subjects with self-reported depression and somatic symptoms had statistically high odds of having higher DF of low-magnitude MMA (defined by ≥ 75th percentile of sample). The association between high DF of low-magnitude MMA and self-reported depression symptoms was significantly augmented among male participants, whereas, the association between high DF of low-magnitude MMA and self-reported somatic symptoms was significantly increased among female participants without pain.
  
  
  CONCLUSIONS
  These pilot data support associations of low-magnitude masseter muscle activities with self-reported depression and somatic symptoms during awake periods.
authors.affiliation: Oral Diagnostic Sciences, University at Buffalo, USA.
authors.forename: Shehryar N
authors.initials: SN
authors.lastname: Khawaja
authors.affiliation: Departments of Orthodontics & Dentofacial Orthopedics and Oral & Craniofacial Sciences, University of Missouri-Kansas City, USA.
authors.forename: Laura R
authors.initials: LR
authors.lastname: Iwasaki
authors.affiliation: Department of Oral Biology, University at Buffalo, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Dunford
authors.affiliation: Departments of Orthodontics & Dentofacial Orthopedics and Oral & Craniofacial Sciences, University of Missouri-Kansas City, USA.
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Nickel
authors.affiliation: Oral Diagnostic Sciences, University at Buffalo, USA.
authors.forename: Willard
authors.initials: W
authors.lastname: McCall
authors.affiliation: Oral Diagnostic Sciences, University at Buffalo, USA.
authors.forename: Heidi C
authors.initials: HC
authors.lastname: Crow
authors.affiliation: Oral Diagnostic Sciences, University at Buffalo, USA.
authors.forename: Yoly
authors.initials: Y
authors.lastname: Gonzalez
keywords: Electromyography; Gender; Masticatory Muscles; Pain; Psychological Factors; Temporomandibular Joint Disorders