Elsevier

Sleep Medicine

Volume 1, Issue 1, 1 February 2000, Pages 21-32
Sleep Medicine

Original article
Pediatric sleep questionnaire (PSQ): validity and reliability of scales for sleep-disordered breathing, snoring, sleepiness, and behavioral problems

https://doi.org/10.1016/S1389-9457(99)00009-XGet rights and content

Abstract

Objective: To develop and validate questionnaire scales that can be used in research to investigate the presence of childhood SRBDs and prominent symptom complexes, including snoring, daytime sleepiness, and related behavioral disturbances.

Background: Obstructive sleep-related breathing disorders (SRBDs) are common but usually undiagnosed among children. Methods to help identify SRBDs without the expense of polysomnography could greatly facilitate clinical and epidemiological research.

Methods: Subjects were children aged 2–18 years who had polysomnographically-confirmed SRBDs (n=54) or appointments at either of two general pediatrics clinics (n=108). Parents completed a Pediatric Sleep Questionnaire which contained items under consideration for inclusion in desired scales.

Results: Item reduction, based on data from a randomly selected 50% of the subjects (group A), produced a 22-item SRBD score that was strongly associated with diagnosis of an SRBD (P<0.0001) in a logistic regression model that accounted for age and gender. Diagnosis was also strongly associated with subscores for snoring (four items, P<0.0001), sleepiness (four items, P=0.0003), and behavior (six items, P<0.0001) among group A subjects. The scales performed similarly well among group B subjects, and among subjects of different ages and gender. In group A and B subjects, respectively, a selected criterion SRBD score produced a sensitivity of 0.85 and 0.81; a specificity of 0.87 and 0.87; and a correct classification for 86 and 85% of subjects. The scales showed good internal consistency and, in a separate sample (n=21), good test-retest stability.

Conclusions: These scales for childhood SRBDs, snoring, sleepiness, and behavior are valid and reliable instruments that can be used to identify SRBDs or associated symptom-constructs in clinical research when polysomnography is not feasible.

Introduction

Obstructive sleep apnea affects 0.7–3.0% of children and can produce excessive daytime sleepiness, behavioral problems, learning disabilities, right-sided heart failure, growth retardation, or failure to thrive [1], [2], [3]. With a prevalence that is not yet known, upper airway resistance syndrome affects children who do not meet diagnostic criteria for OSA but suffer from sleep fragmentation and daytime behavioral morbidity similar to that seen in children with OSA [4]. Most children who have obstructive sleep-related breathing disorders (SRBDs) of either type remain undiagnosed [4]. Recent conservative estimates suggest that more than 80% of adult men and 90% of women with obstructive sleep apnea syndrome have yet to be diagnosed [5], and children probably escape diagnosis more often than adults because they frequently have distinct signs and symptoms that are less widely recognized [6].

The gold-standard in the diagnosis of SRBDs is polysomnography, but the time, effort, and expense of laboratory studies has limited relevant research and particularly epidemiological research that requires large samples. Research in adults has profited from the existence of several validated questionnaire instruments to assess for SRBDs or related symptoms [7], [8]. However, few published questionnaires have been designed to assess for SRBDs and associated symptoms as they occur in children. For example, although excessive daytime sleepiness can affect adults or children with SRBDs, inattention and hyperactivity – often sufficient to result in a diagnosis of attention-deficit/hyperactivity disorder – may be more specific to children with SRBDs [9], [10], [11], [12].

In one previous study, a three-question-item obstructive sleep apnea score allowed reliable diagnosis for only a minority of 23 children referred for possible SRBDs [13]. A subsequent study of these and additional questions also showed that these items had potential value in epidemiological research, though test characteristics were again inadequate to obviate the need for polysomnography in most pediatric patients with sleep-related complaints [14]. Each of these two studies reported on the utility of scores that combined only the three best question-items; one publication did not include the equation for the combined score; and neither score would have been convenient to use in practice because of item-specific coefficients, unique constants, and non-uniform question-item response scales. The scores included items that focused only on observed breathing or snoring during sleep, and neither score included representative items from other symptom-complexes known to be common in childhood OSA. Neither score was tested in a sample that included children with upper airway resistance syndrome. Finally, neither study reported reliability of the questionnaire instruments.

In an ongoing effort to develop a Pediatric Sleep Questionnaire (PSQ) that can help assess children for sleep disorders, we prospectively developed and validated questionnaire scales for SRBDs and related symptoms, including 3 prominent symptom-complexes: snoring, excessive daytime sleepiness, and inattentive/hyperactive behavior. We sought to explore potential utility in clinical research rather than to devise an instrument that reduces the need for polysomnography in clinical practice.

Section snippets

Subjects

Parents of children aged 2–18 years who had polysomnography for clinical indications between April 1996 and September 1998 in the Sleep Laboratory of the University of Michigan were prospectively recruited to give written informed consent and participate in this Institutional Review Board-approved study. We excluded children who had severe medical or mental impairments that precluded parental assessment of usual childhood behaviors. However, more specific inclusion criteria were avoided to

Sample characteristics

Consecutive totals of 54 subjects with SRBDs and 108 general pediatrics subjects provided data suitable for analysis. These represented about 80% of the child-parent pairs approached at the sleep laboratory and about 50% of eligible child-parent pairs approached at the general pediatrics clinics. The yield at waiting rooms of the general pediatrics clinics was lower in part because many parents declined to finish the questionnaire once they were called into their appointment. The mean ages of

Discussion

This study demonstrates the validity and reliability of PSQ scales for childhood SRBD, snoring, excessive daytime sleepiness, and inattentive/hyperactive behavior. Validity was established by comparison to objective criteria – polysomnographically defined obstructive SRBDs – and by demonstration that the questionnaire scales had substantial ability to predict diagnostic classification. The SRBD items that were selected for inclusion in the snoring and behavioral scales segregated well on factor

Acknowledgements

Supported by the National Institute of Health (NINDS grant K02 NS02009) and the University of Michigan General Clinical Research Center (grant M01-RR00042). The authors are also grateful to Morton B. Brown, Ph.D., and Kenneth Guire, M.S., at the University of Michigan School of Public Health for their advice on statistical issues.

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