title: A comparison between jerk-cost derived from a jaw-tracking system with that from an accelerometer.
abstract: Jerk-cost is an inverse measure of movement smoothness and can be calculated from the first-time derivative of acceleration obtained from a tri-axial piezoelectric accelerometer (TPA), or from the third-time derivative of position obtained from a jaw-tracking device. The aims of this study were to determine, in 10 asymptomatic subjects who are chewing gum, (i) jerk-cost measures derived from displacement/time data obtained from the JAWS3D jaw-tracking device and from acceleration data obtained from a TPA used in the same jaw movement recordings, (ii) whether there was a significant relationship between jerk-cost measures derived from both devices and (iii) the degree of agreement between the two measures. Jerk-cost data were calculated in the opening phase, the closing phase, and over the full chewing cycle as the first-time derivative from acceleration obtained from the TPA, and the third-time derivative from JAWS3D for each of the X-, Y- and Z-direction series. There was a significant correlation between both measures of jerk-cost over the full chewing cycle and during jaw-opening (r = 0·65, 0·75, respectively; P < 0·001). There was no significant correlation in the closing phase (r = -0·02, P = 0·99). The Bland-Altman test showed that jerk-cost derived from the JAWS3D can differ by up to 78% below and 21% above that derived from the TPA. These results suggest that jerk-cost measures derived from a jaw-tracking system cannot substitute for jerk-cost measures derived from an accelerometer.
authors.affiliation: Jaw Function and Orofacial Pain Research Unit, University of Sydney, NSW, Australia. minami.rpro@tmd.ac.jp
authors.forename: I
authors.initials: I
authors.lastname: Minami
authors.forename: N
authors.initials: N
authors.lastname: Zhao
authors.forename: K
authors.initials: K
authors.lastname: Oogai
authors.forename: T
authors.initials: T
authors.lastname: Nemoto
authors.forename: T
authors.initials: T
authors.lastname: Whittle
authors.forename: G M
authors.initials: GM
authors.lastname: Murray
mesh_terms: D000054:Acceleration; D056044:Actigraphy / Q000295:instrumentation / Q000379:methods*; D000328:Adult; D000465:Algorithms; D001696:Biomechanical Phenomena; D002638:Chewing Gum; D005260:Female; D006801:Humans; D007568:Jaw / Q000502:physiology*; D008297:Male; D008409:Mastication / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D015203:Reproducibility of Results; D012984:Software; D055815:Young Adult
chemical_list: D002638:Chewing Gum