Body image in people with lower-limb amputation: a Rasch analysis of the Amputee Body Image Scale.

OBJECTIVE

The aim of this study was to examine the psychometric properties of the Amputee Body Image Scale (ABIS) through Rasch analysis, investigating the quality of its rating categories and its reliability and validity.

DESIGN

The ABIS (20 items; ratings of 1-5) and Trinity Amputation Prosthesis Experience Scales (TAPES) were administered by post and completed by 145 people with a lower-limb amputation and currently wearing a prosthesis.

RESULTS

According to Rasch analysis and expert review, some response categories were collapsed and six items were deleted. The remaining 14 items created a revised ABIS (ABIS-R) rated with a three-level rating scale. ABIS-R fitted the unidimensional construct that the scale was intended to measure and demonstrated good reliability (Cronbach's alpha and person separation reliability = 0.87), targeting, and internal construct validity. Moreover, the correlations with the nine TAPES subscales (in particular, r = -0.54 with the general adjustment, r = -0.43 with the social activity restriction, and r = -0.40 with social adjustment) supported the convergent validity of ABIS-R.

CONCLUSIONS

The 14-item ABIS-R demonstrates good psychometric characteristics for measuring body image disturbances in people with lower-limb amputation. These preliminary results suggest the general adequacy of the new instrument and provide a good foundation on which further validation and psychometric studies of the ABIS-R can be conducted.