Development and validation of the Chinese version of the Massachusetts General Hospital Acupuncture Sensation Scale: an exploratory and methodological study

Background The Massachusetts General Hospital Acupuncture Sensation Scale (MASS) is a tool to measure needle sensations. The aims of the present study were to develop a Chinese version and to assess its psychometric properties. Methods This study was a methodological and exploratory study. The English version of the MASS was translated into Chinese using standardised translation procedures. Content validity was conducted by nine acupuncture experts. The prefinal Chinese version (C-MASS) was then administered to 30 acupuncture-naive, healthy subjects. Electroacupuncture was performed on the right LI4 and LI11 acupoints for 30 min. A test-retest reliability measurement was administered 1-2 weeks later. Construct validity was examined by comparing results from C-MASS and the Short-Form McGill Pain Questionnaire (SF-MPQ). The construct validity was further assessed by the principle component analysis. Results C-MASS demonstrated a content validity ratio on relevance and importance from -0.04 to 1.00. Convergent validity was demonstrated by its significant association with the sensory dimension of SF-MPQ (gamma = 0.63, p < 0.05). Discriminant validity was demonstrated by its low association with the affective dimension of SF-MPQ (gamma = -0.3, p = 0.111). A five-factor structure of C-MASS was established by factor analysis. C-MASS demonstrated good internal consistency (Cronbach's alpha = 0.71) and test-retest reliability (intraclass correlation coefficient = 0.92). Since the descriptor 'sharp pain' was not a valid needle sensation related to deqi, this was removed from C-MASS. We renamed the scale as the Modified MASS-Chinese version (C-MMASS). Conclusions A 12-descriptor C-MMASS was established and shown to be a reliable and valid tool in reporting needle sensations associated with deqi among healthy young Chinese people.