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Turkish Validation and Adaptation of Children ’ s Chronotype Questionnaire ( CCTQ )

Objective: Chronotype refers to the time of the day that a person’s physical and cognitive functions are active. Simply this is a circadian phase preference of a person. While some of the people are morning active (so called larks ) others are more active at nights (The owls). The study of circadian rhythms, known as chronobiology, is all about the metabolic and psychiatric differences between people who have different chronotypes. A few tests are used to determine chronotypes. The CCTQ (Children’s Chronotype Questionnaire) is a parentreport, 27-item mixed format questionnaire measuring chronotype of children in multiple domains : the midsleep point on free days (MSF), a morningness/eveningness scale(M/E) score, and a five-point chronotype (CT) score. The aim of this study is adapting Children’s Chronotype Questionnaire (CCTQ) into Turkish language and validating the instrument in Turkish population. Materials and Methods: 101 children aged nine through eighteen constitude the sample of the study. The sample was composed of clinical (n=51) and community groups (n=50). CCTQ and Morningness Eveningness Scale for Children (MESC) questionnaires were applied to children and parents, then the CCTQ and MESC scores were compared to examine the validity of CCTQ. Results: The internal consistency and external validity of the Turkish CCTQ was sufficient to compare MESC-Turkish. As a result of this research carried out in accordance with methodological research principles, correlation between the M/E scores of CCTQ and MESC was significant. Conclusion: The Turkish version of CCTQ has been found to be valid and reliable in Turkish children.


Introduction
Chronotype refers to the time of the day that a person's physical and cognitive functions are active. The study of circadian rhythms, known as chronobiology, is all about the metabolic and psychiatric differences among people who have different chronotypes [1,2]. Some people choose to wake up early in the morning and are most active in the first part of the day while others prefer to wake up later, as their peak time of the day is in the evening, and they prefer to sleep late at night. Morning oriented people are also known as 'early larks' and night active people are named as 'night owls' [3,4].
Morningness-eveningness changes during the lifespan. Although most of children are morning people [5], adolescents become more evening orientated [6][7][8][9]. The switch towards eveningness seems to be associated with pubertal development [10]. At the end of the adolescence period, a switch back to morningness occurs [11].
Circadian rhythm is an increasingly important area in medicine. There is a growing body of literature examining chronotype differences and their relationship with biological and psychiatric variables [12]. The owls are shown to be more likely to have medical problems, like diabetes, hypertension, asthma and fibromyalgia [13,14].
Psychiatry is one of the main sources of chronotype research. Recent studies have demonstrated associations between anxious/depressive symptoms, substance use and eveningness in adolescents [15][16][17] and adults [18,19]. Adolescents displaying eveningness were also found to be more likely to have behavioural and academic problems [20,21].
There are several methods to determine the chronotypes. Actigraphy which is one of the main methods to assess chronotype is the continuous measurement of activity or movement with the use of a small device called an actigraph [22]. It may also have the ability to mark events such as bedtimes or wake times. Despite its high reliability, expensiveness is the major obstacle that limits the use of actigraphy in chronobiology research.
Sleep diary is another method which may be used to determine daily sleep patterns. Diary is composed of a chart with spaces for bedtime, wake time, method of final awakening, frequency of nightly awakening, sleep quality etc. [23]. Although sleep diary is also a reliable and a valid method; it requires a follow up which limits its usage.
Self-report questionnaires are the most widely used tools to determine chronotype in research setting [8,24]. They combine the simplicity and cheapness with high reliability [25,26]. Children's Chronotype Questionnaire (CCTQ) is one of the widely used questionnaires which was designed for measuring the chronotype of the children in multiple domains [5]. The aim of this study is adapting Children's Chronotype Questionnaire (CCTQ) into Turkish language and validating the instrument in a Turkish population.

Sampling
We constitute a study sample from clinical and community settings. The clinical cases (n=51) were randomly selected from children and adolescents aged 9-18 who were admitted to the child and adolescent psychiatry outpatient unit of Atatürk University Medical Faculty. We also included 50 control subjects, 7 students randomly selected from each class level of a primary school from Erzurum. Six children from school sample were excluded due to lack of adequate data on questionnaires. Ethical approval was provided from the ethics committee of Ataturk University. All of the parents were informed about the study and children whose parents agreed to participate were included. Parents whose children were accepted into the study provided written informed consent. Children who had psychosis, autism spectrum disorders and intellectual disability that would affect the analysis were not included in the study.

Instruments Children's Chrono type Questionnaire (CCTQ)
This questionnaire is an adaptation of the Munich Chronotype Questionnaire (MCTQ) [11,26,27] and the Morningness/Eveningness Scale for Children (MESC) [8]. This parent-reported questionnaire for children consists of 16 items on sleep/wake parameters (e.g. bedtime, lights-off time, sleep latency, wake-up time, get-up time, fully alert time, regular naps) for scheduled days and free days, a 10 item M/E scale (range, 10-48) and a single-item on chronotypes (CT) (range, [1][2][3][4][5]. CCTQ asks people about their sleep habits on work and free days. Because most chronotypes tend to accumulate a sleep debt on work days, which is compensated for on free days, MSF (midpoint of sleep on free days, i.e. sleep without social obligations) is adjusted for individual average sleep need. The CCTQ also includes a total score from the Morningness Eveningness (M/E) scale, which is the sum of scores of items. The score of some items are reversed. It provides a range of 10 to 48. Three different measures of children's chronotypes are as follows: morning type, intermediate type and evening type, which are classified using an M/E scale score of ≤23, 24-32 and ≥33. The original CCTQ were translated from English into Turkish and then back to English. We compared the original and back-translated versions regarding wording, meaning and contents for each item and created the final version.

Morningness Eveningness Scale for Children (MESC)
The MESC is a self-administered 10-item scale for adolescents designed to evaluate their diurnal preference (range, 10-43) [8]. A total score is calculated by adding the items. The score of some items are reversed. Higher scores indicate a greater preference for morningness. Classification of diurnal rhythm with using an M/E scale score of MESC-Turkish ver-sion [28] is provided by ≤21, 22-34 and ≥35 scores for evening type, intermediate type and morning type chronotypes respectively.

Procedure
We applied MESC and CCTQ to all children, and only CCTQ to parents. Parents and children were invited to fill out the questionnaires before the child's discharge from outpatient clinic for clinical setting. In community setting, parents were informed by teachers, and then children whose parents accepted were included in the study. Parents were requested to fill the questionnaires at school.

Statistics
We used three different methods to examine the validity of CCTQ. Firstly, we compared the consistency of chronotypes identified by CCTQ and MESC. Secondly, because lower scores in MESC and higher scores in CCTQ indicate more evening orientation, we hypothesized that a negative correlation between scores gathered from two scales may indicate that they are consistent in what they measure. Therefore we checked the correlation of total scores to check this hypothesis. Finally, we calculated Cronbach alpha to test the internal consistency. The data were analysed by using IBM Statistical Package for Social Sciences (SPSS) 21.0 for Windows (SPSS Inc, Chicago, Illinois, USA). The total scores of the M/E scale in the CCTQ were presented as the mean and median according to groups. The scores were almost normally distributed; therefore, we examined the difference in the distributions of scores using the chi-square test and the means using the Student's t-test. Pearsoncorrelations were used to examine the associations of M/E scores between two questionnaires to check for concurrent validity. One-way ANOVA was used to determine the significant relationship between M/E types and clinical/ school groups. Cronbach alpha was calculated for each item to identify the internal consistency of CCTQ. Computations were based on the pairwise deletion of missing data. All analyses were conducted using two tailed tests, and a p value ≤0.05 was considered statistically significant.

Results
The mean age of the participants was 12.5±2.1 years (X±SD); 51.5% (n=52) of respondents were boys; 48.5% (n=49) were girls. The mean MidSleep point on free days (MSF) was 8.86 hours for clinical and 9.70 for the community group; the difference between groups was statistically significant (p=0,05). The mean MSF was 9.20 for boys and 9.36 for girls (p>0.05). The M/E scores was 28.81 among boys and 28.63 among girls (p>0.05). Eleven participants (10.8%) were classified as morning type while 14 (13.8%) ( There was a significant negative correlation between M/E and MESC total scores in contrast to MESC, (p<0.001, r= -0.429). Results of the correlational analysis are presented in Table 2. A positive correlation was found between MSF (p<0.001, r= 0.637), M/E score (p<0.001, r= 0.670) of child and parent CCTQ forms. A positive correlation was found between the single-item question on chronotype interpretation (CT) and M/E scale score of the questionnaire (p<0.001, r= 0.420) Figure 1 shows the scatter graph that imply the negative rela-   Table 3.

Discussion
One of the main finding of this study was the consistency between Turkish forms of MESC and CCTQ. There was a significant negative correlation between CCTQ (M/E) and MESC-T scores as hypothesized. This result supports that Turkish CCTQ provides external validity. The mean values obtained in the CCTQ M/E scores were also similar (mean value, 28.72) with the scores obtained by Werner and colleagues in the validation of original form of CCTQ (mean value, 28.2) [5].
Results of this study show that Turkish CCTQ provides internal consistency with a Cronbach alpha of 0.653. This result was also consistent with those of Werner et al. [5] who found that Cronbach Alpha of CCTQ was 0.81. It was similar to that for the adolescent version of MES (Morningness/Eveningness Scale) by Carskadon and colleagues [8]. It means the internal consistency of Turkish CCTQ was acceptable. Also CT and M/E scores were positively correlated. It is apparent from this correlation that CT and M/E scores resemble to each other which means that improve internal consistency of CCTQ.
There was no difference in the time of day preference across genders in our study. The results of studies of chronotypes regarding gender difference are controversial. While some studies have shown that girls tend to be more morningness than boys, others report no gender difference about the preferences in the sample investigated [25,29,30]. The distribution of the time of day preferences in this study, in which intermediate type was the leading group followed by eveningness and morningness types, was consistent with the findings of previous studies conducted on similar age groups [31].
We also found that CCTQ Turkish form was highly specific for morningness and eveningness, two edges of population, and highly sensitive for the children with quite normal sleep patterns. These are desired specifications for tools assessing chronotype including CCTQ and supports the validity of Turkish form [32]. Low item-total correlations were obtained in some items of the CCTQ. Additionally, internal consistency coefficient did not improve by deleting any item. Several factors may account for this difference, such as culture and social habits [33,34]. Simultaneously, the low correlation in the items can be explained by clock hours. Clock time habits are strongly based on local social, climatic and cultural conditions [35].
Our study had a few limitations. Because the present study was conducted in a geographically limited area, the sample was not enough to represent children countrywide. There are also cultural differences in sleeping arrangement which may have affected the results of the study. To cover these issues, a large-scale study is required to compare the findings on sleep/wake patterns and chronotypes among children which will also assess the cultural aspects such as sleeping with parents or siblings. The present study used the CCTQ to assess the chronotypes of school-aged children based on the observations of their parents. This type of parent-reported response can be confusing in part by subjectivity. Also test-retest reliability could not be checked due to resource-related issues.
In conclusion the internal consistency and external validity of the Turkish CCTQ was sufficient to compare MESC-Turkish. The Turkish version of CCTQ has been found to be valid and reliable in Turkish children and can be used to assess chronotypes in Turkish population.
Ethics Committee Approval: Ethics committee approval was received for this study from the local ethics committee of Atatürk University Faculty of Medicine.
Informed Consent: Written informed consent was obtained from parents of children who participated in this study.

Conflict of Interest: No conflict of interest was declared by the authors.
Financial Disclosure: The authors declear that this study has received no financial support.