The Fugl–Meyer Assessment (FMA) is widely used in stroke research as a gold standard. However, the FMA has not been used in general clinical practice in Japan, which may be related to that the FMA was not translated in the standardized way (including forward translation and back translation). Against the background of linguistic and cultural differences, we translated the standardized FMA into Japanese and adapted it for use in Japan. The aim of the present study is to assess its reliability and validity for the FMA with a Japanese guideline.

A prospective single-center study involving 30 patients with mild-to-severe hemiparesis was conducted. This study was registered in 2016 as a pre-initiation condition. A standardized guidebook for the FMA test administration and scoring was used. The FMA and the Action Research Arm Test, the Box-and-Block Test, and the Motor Activity Log were employed. The simultaneous/non-simultaneous inter-rater reliability and the criterion-referenced validity were assessed in the following ways: the intraclass correlation coefficient (ICC) and the Spearman's rank-order correlation coefficient (Spearman's rho).

The ICC for the simultaneous and the non-simultaneous reliability in the motor section were 0.999 (0.997–0.999, P<0.001) and 0.983 (0.928–0.994, P<0.001). The Spearman's rho for the validity in the motor section ranged from 0.93 to 0.95 (P<0.05).

The FMA with a Japanese guideline reliably assesses the affected upper extremities in patients with hemiparesis after stroke.