Clinimetric analysis of the visual analogue scale and pain free mouth opening in patients with muscular temporomandibular disorder

Abstract

Objective: Perform a clinimetric analysis of the visual analogue scale (VAS) and active pain-free mouth opening (PFMO) in patients with muscular temporomandibular disorder (mTMD). Methods: Reliability (intraclass correlation coefficient=ICC), construct validity, responsiveness (area under the curve=AUC), minimal detectable change (MDC), and minimal clinically important difference (MCID) values were calculated. Results: The VAS-24hr (ICC=0.59), VAS-7day (ICC= 0.54), and PFMO (ICC=0.86) exhibited acceptable reliability. Both the VAS (AUC=0.96) and PFMO (AUC=0.87) exhibited a high level of responsiveness. The MCID was 15.5mm (VAS-24 and VAS-7day) and 3.5mm (PFMO) in the improved group; and 27.5mm (VAS-24), 21mm (VAS-7day), and 6.6mm (PFMO) in the much-improved group. The MDC was 9.6mm (VAS-24), 9.5mm (VAS-7day), and 6.1mm (PFMO). All outcomes demonstrated strong construct validity (Pearson’s r; p<0.001) Conclusions: All three outcome measures demonstrated acceptable clinimetric properties in patients with mTMD at the 3-month follow-up. The MCID lies outside measurement error in all outcomes in the much-improved group.