The methodological study was conducted as follows: a) Translation and adaptation of Burden of adult neurofibromatosis 1 (BoN) to Persian in 7 steps (16). b) Psychometric properties of the questionnaire.
Measures
Personal information checklist includes age, gender, education level, marital and employment status
Participant demographic information was collected from a self-administered questionnaire that included age, gender, level of education, marital status, and employment status.
The Burden of adult neurofibromatosis 1 (BoN) was developed by Armand et al in 2019 (15). It consists of 15 items and is rated on a 6-point scale, ranging from 0 (never) to 5 (constantly). By summing the scores of all items, the total score is calculated and the total score range is from 0 to 75. Higher scores indicate higher levels of burden of neurofibromatosis. The scale exhibited strong psychometric properties, including high internal consistency (α = .91).
Participants
Four hundred patients with neurofibromatosis were invited to participate in this study. Eligibility criteria for participants: a) Over 18 year’s old b) Neurofibromatosis disease approved by the Iranian Neurofibromatosis Association c) No history of psychiatric illness. The questionnaire was prepared electronically on the Google Form platform and the hyperlink sent to the participants and finally 356 people completed the questionnaire. Data collection took place between January 2020 and February 2020.
Translation Process
Initially, two bilingual translators independently translated the questionnaire from English to Persian. Subsequently, by a third bilingual translator, the two translations were compared and transformed to a single text. The text of the current questionnaire was then translated back into the original language by another bilingual translator and compared to the original version of the questionnaire. The opinions of 10 people were applied in the questionnaire and after applying the final corrections, the final version for psychometrics was prepared.
Psychometric Procedure
Content validity includes Content Validity Ratio (CVR) and Content Validity Index (CVI). Twenty experts reviewed the questionnaire items and chose one of the essential, useful but not necessary or unnecessary options (17). According to the Lawshe table, the accepted rate is 0.42 (18). None of the phrases have been deleted in this section. After applying expert opinions and enriching the phrases, 15 other experts reviewed the questionnaire to evaluate CVI (19). The validity of the construct was assessed by exploratory and confirmatory factor analysis (EFA and CFA). Also, 178 participants were used for each method.
Statistical Analysis
For analyzing psychometric properties, Lisrel version 8.80 and SPSS version 18.0 have been used. The basic construct of the items was assessed by the EFA using principal component analysis with direct oblimin rotation. Bartlett's test of sphericity (BTS) was used to assay the correlation matrix between items (p < 0.05), The Kaiser-Meyer-Olkin index (KMO) test was used to assess the quality of sampling (20), and the Kaiser index was used to estimate the number of factors. The results of data analysis and adequacy sampling can be seen in Table 1. Confirmatory factor analysis was performed to evaluate the fit of the model, Goodness of Fit Index (GFI), Normed Fit Index (NFI), Non Normed Fit Index (NNFI), Comparative Fit Index (CFI), Root Mean Square Error (RMSEA), and Degrees of Freedom (CMIN/DF) were used, which are commonly used in determining fitness in CFA (21). The Cronbach's coefficient was calculated to check the internal consistency (22). A test-retest analysis was conducted to assess reproducibility, with a group of subjects who were asked to complete the questionnaire twice, with an interval of at least 14 days in between (23).
Table 1
Kaiser-Meyer-Olkin Measure of Sampling Adequacy | 0.902 |
Bartlett’s Test of Sphericilty | Approx. Chi-Square | 1272.551 |
df | 105 |
Sig. | < 0.001 |