The Female Sexual Function Index (FSFI): development of a Japanese version.

INTRODUCTION: A valid and reliable self-administered scale to measure multidimensional aspects of female sexual function is needed in Japan, as sexual dysfunction is quite common in Japanese women.

AIM: The aim of this paper is to develop a Japanese translation of the Female Sexual Function Index (FSFI-J), 3-month version, and to measure its psychometric reliability and validity.

METHODS: Following a language validation process and pilot tests, we modified the scale by adding some instructions and answer options. A cross-sectional survey to examine psychometric reliability and validity of FSFI-J was conducted with 126 healthy Japanese women in partnered relationships. Reliability studies on test-retest and on internal consistency were conducted using the intraclass correlation coefficient (ICC) and Cronbach's α coefficient, respectively. A validity study was conducted on aspects of face, construct, concurrent, and discriminant validity.

MAIN OUTCOME MEASURES: The main outcome is the psychometric reliability and validity of FSFI-J.

RESULTS: FSFI-J showed high test-retest reliability (ICC > 0.78) and high internal consistency (Cronbach's α > 0.84). In terms of face validity, FSFI-J was found to be understandable and can adequately measure various aspects of female sexual function. Regarding construct validity, exploratory factor analysis of FSFI-J supported a five-factor solution, consisting of desire/arousal, lubrication, orgasm, satisfaction, and pain. This domain structure was identical to that of the original FSFI. Regarding concurrent validity, FSFI-J total score and domain scores showed significant correlations (Pearson's r = -0.613 for total score) with the sexual function domain of the perimenopausal subjective symptom inventory and overall sexual satisfaction as measured by a visual analog scale (Pearson's r = 0.387). For discriminant validity, the regular menstruation group showed significantly higher FSFI-J scores than the menopause group in the total score and all subdomain scores except sexual satisfaction.

CONCLUSIONS: The FSFI-J is a valid and reliable instrument to measure multidimensional aspects of sexual function in healthy Japanese women who are in partnered relationships.