OBJECTIVES: To assess whether: a) application of a vibrotactile stimulus is a reliable test. b) vibrotactile stimulus differentiates TMJD-pain patients from controls.
METHODS: Fourteen female TMJD subjects with arthromyalgia pain (RDC/TMD Ia/b and IIIa) were compared to 13 age and gender matched controls in a parallel group cross-sectional study. Vibrotactile QST was performed using an electric toothbrush (Braun Oral-B), applied with 1 lb. pressure for 30 seconds in three locations on the side of greatest pain: over the lateral pole of the temporomandibular joint, mid-masseter and anterior temporalis. Pain intensity (0-10) was recorded following the vibrotactile stimulus at 0, 15, 30 and 60 seconds. For test-retest reliability, measures were repeated on 8 participants, 2-12 hours apart, and intraclass correlation coefficients (ICC) computed. Case versus control differentiation involved comparison of “area under the curve” (AUC), with a maximum potential area of 10 (pain) X 60 (seconds) = 600/test site, and 3(600) = 1800 for all three TMJD sites pooled together. A receiver operating characteristic (ROC) curve was used to determine cutoff AUC scores for maximum sensitivity and specificity to differentiate cases from controls.
RESULTS: Test-retest reliability for vibrotactile stimulus resulted in an ICC = 0.99 for masseter site and ICC = 0.84 for pooled TMJD sites. A ROC-determined AUC cutoff score of 60 (out of 600) for the masseter site and 140 (out of 1800) for pooled TMJD sites resulted in a sensitivity of 57%, and a specificity of 92%, for both masseter and pooled TMJD sites.
CONCLUSION: Vibrotactile QST has excellent test-retest reliability, modest sensitivity, and good specificity for differentiating TMJD pain patients from controls. This study was supported by the University of Minnesota, School of Dentistry.