This study is a cross-sectional study. In this study, 311 mothers of children aged 1-5 years in Isfahan were randomly selected. First, the goals of this study were explained to mothers. Four hundred four mothers engaged in this study. We asked about the history of psychiatric illnesses in mothers. Almost 14% of the mothers with at least one psychiatric disorder like obsessive-compulsive disorder or stress spectrum disorder were excluded. Then, we asked about the clinical history of their children. All children with critical medical conditions like CNS abnormalities were excluded. Also, incomplete answers were omitted. Finally, a crowd of 311 children remained in this study. Two weeks later, a group of 30 participants answered the questionnaires for the second time.
Translation
We used forward-backward translation and the pre-test. In this way, the English version of TCSQ was translated into Persian by two people who were proficient in translating medical texts and with experience in translating questionnaires. Then the translations were compared, the questions were matched in terms of meaning and concept, and a Persian version of this tool was finally prepared by selecting the best options. Then, to ensure that the Persian translation matches the original text and the sentences are clear, the translated version was translated into the original language by two other fluent English translators who had not seen the initial questionnaire before.
Sample Size
Psychometric instructions suggest 8 to 12 samples for each question [20]. We selected 404 Iranian children between the ages of 1 and 5.
Material
Tayside Children's Sleep Questionnaire (TCSQ)
As mentioned, TCSQ is a 10-item questionnaire to assess DIMS in children one to five years old. The first version was developed in 2005 by McGreavey et al. with Cronbach's alpha of 0.85. The scoring of this questionnaire is in the form of Likert. The first nine questions score from zero to four. The last question is considered separately [18].
BEARS questionnaire
The psychometric properties of the Persian version have been approved by Mohammadi et al., and the coronachs alpha was more than 0.8. This questionnaire consists of two parts. One section is used for children two to six years old, and the other one is used for children seven to 12 years old. In this study, we used the first part of this test. If the mother puts a positive sign in front of questions, it indicates that a sleep disorder exists in her child. In this study, we used this questionnaire to assess convergent validity [21].
Inclusion criteria
Children aged between one and five years old Who live with both biological parents are included in this survey.
Exclusion Criteria
Mothers declare that they had any psychiatric disorder, or their Children with any history of certain medical conditions three months ago or who lost their parent(s) during the study are excluded.
Test-retest reliability
We used the internal consistency coefficient known as Cronbach's alpha to calculate the P-TCSQ internal reliability. Intra-class correlation coefficient (ICC) was also calculated by repeating the survey on 30 mothers after 2-4 weeks [22].
Validity:
Face Validity:
The opinions of three experts about the clarity, simplicity, and eloquence of P-TCSQ were asked.
Content Validity:
The questionnaire was given to three experts to determine whether the measured elements can measure the concept and whether the questions used in the questionnaire represent the whole questions or not.
Convergence validity
We used the BEARS sleep questionnaire to assess the convergent validity between TCSQ and BEARS.
Exploratory Factor Analysis (EFA)
For construct validity, Exploratory Factor Analysis (EFA) is used with Varimax rotation. Also, to evaluate the suitability of the data for factor analysis, two preliminary tests of sampling adequacy, KMO and Bartlett's Test at P<.0001 level, were used. For analyzing the relevant factor in sampling adequacy, a score of 0.6 and above was considered.
Statistical analysis
We extracted data from Google Form and imported it into Excel. Then, using the "replace" tool, answers are converted to the Likert scale according to the guideline of TCSQ. Then we used STATA 14th version for factor analysis and SPSS 16th version for descriptive statistics. Cronbach's alpha is calculated for the internal consistency of TCSQ. Test-retest reliability, confirmed by Intra-class coefficient (ICC). Spearman correlation coefficient and EFA are used to perform factor analysis.