1-Week Epworth Sleepiness Scale for Children and Adolescents Validated for Pediatric Narcolepsy

Diane R. Menno, PhD, MS

Data from a recent study support validation of the 1-week Epworth Sleepiness Scale for Children and Adolescents (ESS-CHAD) in pediatric narcolepsy, making it the first study to support the modified scale in pediatric participants under the age of 12 years.¹ 

Investigators, including Diane R. Menno, PhD, MS, associate director biostatistics, Jazz Pharmaceuticals, assessed the validity of the ESS modified for children between the age of 7 and 16 years. A total of 100 children with narcolepsy with cataplexy were included in analyses, with a mean age of 11.9 years (standard deviation [SD], 2.39). The mean 1-week ESS-CHAD value was 14.4 at baseline, which was above the upper limit of normal for the ESS, which is 10. Most children (68.0%) were taking sodium oxybate (SXB)(Xyrem; Jazz Pharamaceuticals), stimulants, or both upon entering the study.

For the full 1-week ESS-CHAD validation population, the internal consistency, as assessed by Cronbach’s alpha, was 0.750 (95% CI, 0.681-0.819). In the 7-11 years subgroup (n = 36) and the 12-16 years subgroup (n = 64), Cronbach’s alpha was 0.755.

When evaluating the intraclass correlation coefficient for the test-retest reliability assessment, investigators excluded 36 patients from a subset of SXB-naïve patients who reported stimulant use at baseline, leaving at total of 64 patients. Thirty-two were SXB–naïve and not taking stimulants at study entry and 32 were taking SXB at study entry with or without stimulants. The intraclass correlation coefficient for the test-retest reliability assessment was 0.755 (95%, 0.626-0.844).

Measured as the mean within-person change in 1-week ESS-CHAD score over time in the overall population, responsiveness to change in SXB-naïve patients (n = 59) from baseline to end of the stable-dose period, where patients were taking a titrated amount of SXB, was –6.31 (95% CI, –7.61 to –5.00; nominal P <.0001). The mean scores of convergent construct validity for girls (n = 40) and boys (n = 60) were 13.98 (SD, 4.440) and 14.65 (SD, 4.050), respectively (nominal P = .4430). Mean scores for divergent construct validity were 16.31 (SD, 2.978) in those who were not taking SXB or stimulants upon entering the study (n = 32) and 13.47 (SD, 4.400) for those who were taking SXB with or without stimulants at study entry (n = 68; nominal P = .0003).

“As no version of the ESS-CHAD has previously been validated in individuals younger than 12 years of age, and the validity of the 1-week ESS-CHAD has not previously been assessed in a pediatric population of any age, results in subgroups of participants aged 7–11 years and 12–16 years are of interest,” Menno et al wrote.¹

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“The results support the internal consistency, test-retest reliability, responsiveness to change, and construct validity (both convergent and divergent) of the 1-week ESS-CHAD in pediatric participants. Subgroup analyses confirmed the validity of this tool in participants aged 7–11 years and 12–16 years. The 1-week ESS-CHAD may be a useful instrument for assessment of excessive daytime sleepiness in pediatric patients,” the authors added.

The study analyzed data from a sodium oxybatephase 3 study in patients with narcolepsy with cataplexy (NCT02221869).² Prior to entering a 2-week stable-dose period, SXB-naïve participants completed and open-label titration period, and participants taking SXB upon study entry entered a 3-week stable-dose period. Participants completed the 1-week ESS-CHAD at each study visit, including the screening visit, the baseline visit, and the visit at the end of the stable-dose visit. For SXB-naïve participants, the baseline visit was at the beginning of the open-label titration period, while the baseline visit for those taking SXB at study entry was at the beginning of the stable-dose period.

The study population only included patients with narcolepsy, as opposed to including others with excessive daytime sleepiness that may be caused by other disorders, which was noted by investigators as a limitation. The specificity of the study population further limits the ability to generalize the validation of the scale to all children and adolescents. Children under the age of 7 years were also not included, and the confirmatory factor analysis was not conducted for the validation of single construct of sleepiness.

REFERENCE
1. Wang YG, Menno D, Chen A, et al. Validation of the Epworth Sleepiness Scale for Children and Adolescents (ESS-CHAD) questionnaire in pediatric patients with narcolepsy with cataplexy aged 7-16 years. Sleep Med. 2022;89:78-84. doi:10.1016/j.sleep.2021.11.003
2. Plazzi G, Ruoff C, Lecendreux M, et al. Treatment of paediatric narcolepsy with sodium oxybate: a double-blind, placebo-controlled, randomised-withdrawal multicentre study and open-label investigation. Lancet Child Adolesc Health. 2018;2(7):483-494.doi:10.1016/S2352-4642(18)30133-0