A comparison between jerk-cost derived from a jaw-tracking system with that from an accelerometer

作者：Minami I^*; Zhao N; Oogai K; Nemoto T; Whittle T; Murray G M

来源：Journal of Oral Rehabilitation, 2011, 38(9): 661-667.

DOI：10.1111/j.1365-2842.2011.02200.x

• jaw movement
• mastication
• accelerometer
• jerk-cost
• acceleration
• jaw-tracking system

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.

• 出版日期2011-9