Reliability and Validity of the Japanese Perme ICU Mobility Score: An Initial Psychometric Evaluation

Objectives : The Perme ICU Mobility Score is widely used to assess functional status, but no version of this assessment tool has been validated for use in Japan. This study aimed to translate the Perme Score into Japanese and evaluate its reliability and validity.
Methods : Following forward–backward translation, the Japanese Perme Score was tested at ICU discharge. Inter-rater reliability was examined using weighted kappa coefficient. Construct validity was assessed through correlations with the Medical Research Council Sum Score (MRC-SS), Functional Status Score for the ICU (FSS-ICU), and ICU Mobility Scale (IMS). Predictive validity for activities of daily living (ADL) independence (Barthel Index ≥ 85) and discharge destination was evaluated using Receiver operating characteristic (ROC) analysis. Floor and ceiling effects were also analyzed.
Results : In 69 patients, the Japanese Perme Score showed high inter-rater reliability (κ=0.83). It showed moderate correlation with FSS-ICU (rho=0.61) and IMS (rho=0.73), and it showed weak correlation with MRC-SS (rho=0.36). Predictive validity for ADL independence and home discharge yielded AUCs of 0.76 and 0.73, respectively. A ceiling effect was noted in 10% of cases, with no floor effect.
Conclusions: The Japanese Perme Score is a reliable, valid instrument for evaluating physical function at ICU discharge.