## 4 Discussion  
The aim of this study was to achieve a cross-cultural adaptation of the ABIS for Spanish-speaking lower limb amputees. The ABIS-E analysis showed excellent test-retest reliability (evaluated with intraclass correlation) and an adequate-good internal consistency (evaluated with Cronbach's alpha). Moreover, the final scores of ABIS-E obtained a high correlation with other functional capacity, depression, anxiety, and quality of life questionnaires and scales. This is the first study carried out to validate a questionnaire of these characteristics in a Spanish amputee population. No relevant troubles were found during the process of translation and cross-cultural adaptation, which was performed according to the international recommendations [19; 20], and participants reported no problems in understanding the proposed items. The sample for this work was recruited using the same inclusion and exclusion criteria and its characteristics are like other validation studies of ABIS [8; 15; 16; 17]. In all studies, adult patients with enough cognitive function to understand and complete the questionnaire were selected. Regarding sex distribution, the predominant presence of men was common in all validation studies (65.8% in ours). The results match with other the scientific literature reviewed, in which male gender is a risk factor for suffering complications resulting in amputation, especially in the case of diseases like diabetes [43]. Our results show good reliability of the Spanish version of the ABIS-E questionnaire, demonstrated by good internal consistency measured by Cronbach's alpha with a value of 0.753 for the test and 0.806 for the retest. Validation studies in French, Chinese, Turkish, and Portuguese [8; 15; 16; 17] showed higher alpha values for the test (>0.8). Although a value higher than 0.7 is considered enough for a good reliability of the scale, the difference between test and retest alpha values could be explained by better comprehension of the items or even that participants perceived the items to be more homogeneous while answering them in the second round. We found excellent test-retest reliability (ICC = 0.847, 95%CI (0.777-0.904)). We used the questionnaire at a fair interval (7-10 days) to ensure the internal validity of the design, avoiding both a quick measurement that could condition a recent recall of the application and a delay that could cause excessive changes in the responses. Our results are consistent with the ICC obtained in the validation studies in French (ICC = 0.87) [8] and Chinese (ICC = 0.86) [15] versions, but they are slightly inferior to the Turkish version (ICC = 0.94) [16], which may indicate that in this mentioned study the sample was more homogeneous and the variance of the data for each measurement was smaller. By analyzing the structure of the ABIS-E, we found three main factors: Factor 1 was a personal factor (items 6, 8, 1, 16, 12, 10, 11, 4, 9, 2, and 5); factor 2 was social factor (items 14, 20, 18, 17, 3, 15, 19, and 7), and factor 3 was a functional factor (items 7 and 13). These findings confirm the results of [PERSON] et al. [15] and [PERSON] et al. [16], who also found three factors that differentiate the personal, social, and functional dimensions. The time since amputation and its relationship with ABIS-E scores seem to indicate that the longer the time since amputation, the greater the integration of the amputation into the patient's body image and the lower the discomfort with the new situation. These data confirm the idea that a recent amputation has a great impact on this perception of the body schema and on the limitations of function perceived by the patient, which decrease with time. In our correlation analysis, we observed that factor 1 (personal) of the ABIS-E questionnaire had an average correlation with the HADS questionnaire, both for the anxiety and depression dimensions. This agrees with the findings of [PERSON] et al.