Jaw movements in patients with a history of pain: an exploratory study

The aims were to determine whether individuals with a past history of pain exhibit (i) altered jaw movement (e.g. reduced amplitude, increased jaw movement variability) in comparison with matched asymptomatic controls, and (ii) correlations between psychological measures (e.g. catastrophising) and altered jaw movement variables. Sixteen participants with a history of trigeminal neuropathic pain (TNP) and 15 age- and gender-matched healthy controls had jaw movements recorded during open/close, free gum chewing and chewing at standardised rates. All completed the Pain Catastrophising Scale (PCS), the Pain Self-Efficacy Questionnaire (PSEQ), and the Depression, Anxiety and Stress Scales (DASS). Velocity and amplitude for open/close and chewing, as well as variability, bias and mean square error for open/close jaw movements were compared between groups. Spearman's rank correlation coefficient was used to relate kinematic variables with psychological variables. Statistical significance: P < 0·05. There were no significant differences in mean jaw velocity and amplitude between the TNP and control groups during the open/close jaw movements or free or standardised chewing. In comparison with control, the TNP participants exhibited significantly greater variability, bias and/or mean square error during slow and/or fast opening, and significantly greater variance in velocity and/or amplitude during free and standardised chewing. There were significant negative correlations between PCS scores and velocity and/or amplitude of free and/or standardised chewing. This exploratory study suggests that individuals with a history of pain have altered patterns of jaw movements in comparison with asymptomatic control participants and that catastrophising may play a role in the manifestation of these altered jaw movements.