title: Effects of Age, Sex, and Body Position on Orofacial Muscle Tone in Healthy Adults.
abstract: OBJECTIVE
  Quantification of tissue stiffness may facilitate identification of abnormalities in orofacial muscle tone and thus contribute to differential diagnosis of dysarthria. Tissue stiffness is affected by muscle tone as well as age-related changes in muscle and connective tissue.
  
  
  METHODS
  The Myoton-3 measured tissue stiffness in 40 healthy adults, including equal numbers of men and women in each of two age groups: 18-40 years and 60+ years. Data were collected from relaxed muscles at the masseter, cheek, and lateral tongue surfaces in two positions: reclined on the side and seated with head tilted.
  
  
  RESULTS
  Tissue stiffness differed across age, sex, and measurement site with multiple interaction effects. Overall, older subjects exhibited higher stiffness coefficients and oscillation frequency measures than younger subjects whereas sex differences varied by tissue site. Effects of body position were inconsistent across tissue site and measurement.
  
  
  CONCLUSIONS
  Although older subjects were expected to have lower muscle tone, age-related nonmuscular tissue changes may have contributed to yield a net effect of higher stiffness. These data raise several considerations for the development of accurate normative data and for future diagnostic applications of tissue stiffness assessment.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Dietsch
authors.forename: Heather M
authors.initials: HM
authors.lastname: Clark
authors.forename: Jessica N
authors.initials: JN
authors.lastname: Steiner
authors.forename: Nancy Pearl
authors.initials: NP
authors.lastname: Solomon
mesh_terms: D000293:Adolescent; D000328:Adult; D000375:Aging / Q000502:physiology*; D015992:Body Mass Index; D004548:Elasticity; D005152:Facial Muscles / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009129:Muscle Tonus / Q000502:physiology*; D009842:Oligopeptides / Q000502:physiology*; D012727:Sex Characteristics; D014059:Tongue / Q000502:physiology*; D055815:Young Adult
chemical_list: D009842:Oligopeptides; C071400:poststatin