Before starting the translation, we obtained the authors’ agreement of the scale.
Translation (Fig. 1)
These scales are translated and culturally adapted to the Moroccan dialect following the guidelines suggested by Guillemin et al. [7]. Four main steps were taken: forward translation, back translation, committee review, and pretest.
First step
The translation of the original English version of the scales was done independently by two translators fluent in English.
The two translators carried out a cross-cultural adaptation of the concepts rather than a simple linguistic translation.
The translation coordinator produced a synthesis of the two translated versions, with a detailed report of the difficulties and resolutions.
At the end of this step, a preliminary Moroccan Arabic version of the three scales is obtained.
Second step
The preliminary version was then back-translated into English by two bilingual translators. They are unfamiliar with the original English version.
The coordinator accomplished the synthesis of the two back-translated versions with a detailed report of the difficulties of back-translation.
Third step
A committee of experts, including translators and psychiatrists, revised this process, and they discussed the semantic equivalence to obtain a pre-final version.
Fourth step
Pre-test
To get the final version, we test the pre-final version on adult subjects. This process helps us to eliminate any ambiguity and to check the understanding of the different items. The test was carried out on ten individuals belonging to different social categories and educational levels.
The final version was subjected to psychometric analysis.
Validation
Sample size
We determined the sample size on the Streiner curve, which estimates the number of subjects needed according to the desired reliability coefficient and degree of precision. For an ICC of 0.70 and an accuracy of ± 0.10, the number needed is approximately 120 subjects [8].
Study population
We selected 120 medical students, medical staff, and administrators working at university hospital centers. We can easily administer the scale in two steps for this population. Also, this community is more likely to have sleep disorders.
The following are the inclusion criteria:
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Participants speak the Moroccan dialect, aged over 18 years old.
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All participants were informed about the study. We respect the anonymity and confidentiality of participants during the collection of data.
The following are the exclusion criteria:
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Those who do not speak the Moroccan dialect
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Subjects with an intellectual disability or a medical condition making it difficult to understand the questionnaire
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Subjects who did not consent to participate in the study
Data collection
Data collected
We carried out a self-administered non-anonymous questionnaire in the Moroccan dialect. It contained the socio-demographic characteristics (age, sex, marital status, profession, and socio-economic level) and the Moroccan version of the scale.
We had to pass the scales two times (T1, T2) to each individual in the sample.
We obtained oral and written consent from each participant before starting the study.
Collection methods
The translated versions were administered two times by two investigators. The second administration made 10 days after the first.
Ethical aspects
The Ethics Research Committees of the Faculty of Medicine and Pharmacy Oujda approved the study. The study was carried out under conditions that comply with the ethical recommendations of the Helsinki Declaration. We obtained signed consent from participants.
Data analysis
Descriptive analysis
Descriptive statistics were generated to summarize the demographic characteristics of the participants and to evaluate the score distribution. Quantitative variables were described using means, standard deviations, and range of scores. Qualitative variables were expressed as percentages.
Psychometric properties
The reliability was estimated by measuring the internal consistency and the test-retest reliability of the questionnaire. The internal consistency of the Moroccan Arabic versions of the ISI scale was assessed for the multi-item questionnaire scales using Cronbach’s coefficients. Internal consistency of a magnitude of 0.70 or greater was sought. Test-retest reliability was estimated by calculating the ICC derived from a two-factor analysis of variance with a random effect [9]. A correlation greater than 0.60 is usually desirable, and values greater than 0.90 indicate excellent reliability [10]. Besides, we calculated the kappa coefficient, with a value close to 1 reflects a high level of agreement [11, 12].
The contribution of each item to the total score was assessed using item-total correlation. Corrected item-total correlation ≥ 0.3 are considered acceptable [13].
Since there was neither a relevant criterion-related estimator of prediction nor a well-defined domain of content for determining validity, construct validity should also be obtained in future studies to further verify the psychometric properties of this version.
Statistical analysis of the study population was performed using the SPSS 21.0 software.