In this pilot study, our multidisciplinary team created a Czech questionnaire for identifying children at risk of POSA. This is the very first such questionnaire originally designed in the Czech language and tested in the Czech population. Examinations such as PSG or polygraphy are known to have a good diagnostic ability to reveal POSA; however, given the lack of and workload of sleep laboratories for children and specialists in this area in the Czech Republic, these examinations are often inaccessible. In view of the fact that early diagnosis and proper treatment are crucial in children suffering from POSA, an ideal screening tool that could reveal the need for these examinations, should not be only easy to use and interpret but, most importantly, widely accessible. The use of a sleep questionnaire focusing on children can be a workable way to improve the early detection of POSA risk.
Considering the fact that several pediatric sleep questionnaires abroad2-7, we initially wanted to simply translate a highly evaluated questionnaire and adapt it from English to Czech. We searched the literature and based on several studies, including a recent meta-analysis published by Wu et al., we have chosen the PSQ as it was found to have the highest screening sensitivity for detecting mild POSA and sensitivity comparable to pulse oximetry in patients with moderate and severe forms of POSA [8]. Based on these results, the authors recommended a combination of PSQ and pulse oximetry for early detection of POSA [8]. Another review identified the PSQ as the only questionnaire that is diagnostically accurate enough to screen for impaired breathing in children, while also highlighting the importance and benefit of involving dentists in the primary screening of POSA [9].
However, after the translation and adapting PSQ-SRBD scale4 in collaboration with a multidisciplinary team of professionals and experts from different medical fields associated with pediatric sleep medicine in the Czech Republic, we agreed on the fact that a simple translation would not be sufficient. We considered also the cultural differences and differences in the structure of sentences in both Czech and English languages and their exact meaning and decided to take further steps and design a questionnaire for identifying POSA risk for Czech users, which we named SEN CZ.
After preliminary testing of SEN CZ ver. 1, we proceeded to further improve it to produce SEN CZ ver. 2, which has already achieved very good results (Cronbach's α = 0.928); however, it was quite lengthy, and we have decided to shorten it as much as possible. The final version of the SEN CZ kept the good sensitivity and specificity, as well as reliability but contains less than half the items compared with the SEN CZ ver. 2, making it more user-friendly. In the context of sensitivity and specificity, the performance of the final version of the SEN CZ is very good, comparable with the best sleep questionnaires included in the meta-analysis by Wu et al. [8].
In our questionnaire, we originally intended to keep dichotomous items for the simplicity of assessment; however, to detect the behavior in children, the use of Likert scale is often preferred to dichotomous questions (yes/no/unknown) [12]. For screening purposes, it is better if we capture the answer on a scale rather than dichotomously as it is more accurate.
The majority of the items in the final version of the SEN CZ cover very similar areas of POSA symptoms as items in foreign pediatric sleep questionnaires [2–7]. This supports their importance as factors contributing to this disease. In our questionnaire, based on the results of the validation, we have excluded several items associated with the nocturnal symptoms due to their high difficulty for parents. Even though snoring and difficulty breathing during sleep are probably most common complaint voiced by parents of children with POSA [13], more recent studies reported that parents were able to report snoring in only 15% of children diagnosed with POSA [14, 15]. These findings are suggestive of the fact that parents may often fail to notice the nocturnal symptoms, especially if the children have a separate room, or if not enough attention is paid to this problem.
In our questionnaire, a lot of items are focused on the area of daytime symptoms. For example, in the case of nasal obstruction and adenotonsillar hypertrophy, a transition to mouth breathing occurs, which subsequently affects changes in the orofacial region, such as the narrow hard palate, posteriorotation of the mandible and/or disproportions in the sagittal plane, as well as the elongation of the lower third of the face, which can be expressed in varying degrees and forms [16, 17]. These features may present risk factors for the development of POSA; moreover, mouth breathing preference has been identified as an early contributor to SRBD that can be often found in primary snorers and patients with POSA [18, 19]. At the same time, these contributing factors may be, compared to nocturnal symptoms, easily detectable also by parents, which makes them important for screening.
Interrupted sleep and nocturnal hypoxia affect, among other things, the prefrontal cortex and thus the cognitive executive functions of the individual [20]. Affected children have impairments in planning, plan execution, organization, decision-making, and information processing. These factors, together with impaired attentional retention, impaired concentration, impulsivity, hyperactivity, and emotional lability, often cause errors of inattention and impaired school performance [21–23].
Children with POSA also tend to have increased irritability (or even aggression) and may show disinterest in daily activities and tendencies to depression. It has even been suggested that sleep disruption and difficulty in early childhood may predict behavioral and emotional problems during adolescence [24]. There is also evidence of a significant association between reduced or disturbed sleep and the severity of behavioral changes. Studies also suggest that children presenting with POSA display symptoms of attention deficit and hyperactivity disorder (ADHD) more often than those without it [25, 26]. Most studies agree on a bidirectional association between POSA and ADHD [27].
The results of the factor analysis and logistic regression indicate that the SEN CZ is slightly more likely to recommend a comprehensive POSA examination when it is not needed than to fail to recommend an examination when it should be performed. Given the screening nature of the questionnaire, this is a very good result. Moreover, the SEN CZ could be also a good predictor of ADHD. Therefore, it might be useful to continue the research with data obtained from children diagnosed with ADHD. We may then be able to analyze which items discriminate well between POSA and ADHD (i.e., identify questions in which parents of children with POSA score significantly differently than parents of children with ADHD).
Even though according to the latest AASM guidance, PSG is the gold standard for diagnosing pediatric sleep disorders [28] it may not be readily available in all clinical settings. In our study, we encountered practical challenges in accessing PSG for children due to its limited availability in the Czech Republic and long waiting times. In light of these limitations and considering that HSAT is recommended as a screening tool before the referral for PSG, when applied under controlled settings by sleep specialist [29, 30] we opted for including HSAT, polygraphy, as a part of our validation process. Important fact is also that SEN CZ should only be used as the first alert of generally disturbed nocturnal breathing with recommendation for further examinations, not to serve as a replacement for any sleep-monitoring or as a precise diagnostic tool.