Translation and Psychometric Evaluation of the Mahoney Pain Scale Among Iranian Elderly With Dementia: A Methodological Study.

Valid and reliable measurement tools are necessary for pain assessment among the elderly with dementia. This study aimed to translate the Mahoney Pain Scale (MPS) into Persian and evaluate its psychometric properties among Iranian elderly with dementia. In this methodological study, after translating and assessing the face and content validity of MPS, 100 elderly with dementia were selected via convenience sampling from nursing homes and clinics in Kashan in 2018-19; then, MPS was completed for them both at rest and during a movement pain protocol. MPS was assessed by exploratory factor analysis, known-group comparison, convergent validity, internal consistency, equivalence, and stability. The factor analysis revealed a one-factor structure, which explained 57.11% of the total variance. The Persian MPS differentiated patients with and without known painful conditions, as well as pain at rest and during the movement pain protocol (p < .0001). There was a significant positive correlation between the scores of MPS and PACSLAC-II (r = .87, p < .0001). The Cronbach's α, intraclass correlation coefficient and standard error of measurement of MPS were .91, .79, and ±1.37, respectively. As a valid and reliable tool, the Persian MPS can be used for pain assessment among Iranian elderly with dementia.