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A comparison between jerk‐cost derived from a jaw‐tracking system with that from an accelerometer
Author(s) -
MINAMI I.,
ZHAO N.,
OOGAI K.,
NEMOTO T.,
WHITTLE T.,
MURRAY G. M.
Publication year - 2011
Publication title -
journal of oral rehabilitation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 93
eISSN - 1365-2842
pISSN - 0305-182X
DOI - 10.1111/j.1365-2842.2011.02200.x
Subject(s) - jerk , acceleration , accelerometer , mathematics , jaw jerk reflex , control theory (sociology) , computer science , medicine , physics , physical medicine and rehabilitation , electromyography , artificial intelligence , control (management) , classical mechanics , operating system
Summary 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.