Development and Validation of the Pediatric Hypersomnolence Survey

Abstract

Background and objectives: Narcolepsy and idiopathic hypersomnia usually begin in early adolescence, but diagnostic delays ranging from 5 to 10 years are common, affecting disease burden. To improve early identification of these treatable conditions, we developed and validated the Pediatric Hypersomnolence Survey (PHS).

Methods: Content was developed through literature review, patient focus groups, interviews with experts in the field, and field testing. We then validated the 14-item self-reported survey across 3 hospitals and web recruitment from patient groups. In the validation phase, we recruited a total of 331 participants (patients with narcolepsy type 1 [n = 64], narcolepsy type 2 [n = 34], idiopathic hypersomnia [n = 36], and other sleep disorders [n = 97] and healthy controls [n = 100], ages 8-18 years) to complete the survey. We assessed a range of psychometric properties, including discriminant diagnostic validity for CNS disorders of hypersomnolence using receiver operating characteristic curve analysis and reliability across a 1-week period.

Results: Confirmatory factor analysis indicated a 4-domain solution with good reliability expressed by satisfactory omega values. Across groups, the PHS total score showed appropriate positive correlations with other validated surveys of sleepiness (r = 0.65-0.78, p < 0.001) and negative correlations with multiple sleep latency test measures (mean sleep latency: r = -0.27, p = 0.006; number of sleep-onset REM periods: r = 0.26, p = 0.007). Compared to controls and patients with other sleep disorders, the area under the curve for participants with narcolepsy or idiopathic hypersomnia was 0.87 (standard error 0.02, 95% CI 0.83-0.91) with high sensitivity (81.3, 95% CI 73.7%-87.5%) and specificity (81.2%, 95 CI 75.1%-86.4%). Test-retest reliability was r = 0.87.

Discussion: The PHS is a valid and reliable tool for clinicians to identify pediatric patients with narcolepsy and idiopathic hypersomnia. Implemented in clinical practice, the PHS will potentially decrease diagnostic delays and time to treatment, ultimately reducing disease burden for these debilitating conditions.

Classification of evidence: This study provides Class III evidence that the PHS accurately identifies patients with central disorders of hypersomnolence.

Figure 1. Protocol and Study Enrollment by Phase

IH = idiopathic hypersomnia; NT1 = narcolepsy type 1; NT2 = narcolepsy type 2.

Figure 2. Optimal Factor Solution of PHS Over Time

The 4 latent factors were as follows: F1, excessive daytime sleepiness; F2, cataplexy; F3, REM-related phenomenon; and F4, fatigue. PHS = Pediatric Hypersomnolence Survey. (A) Time 1 and (B) time 2.

Figure 3. PHS Total and Subscale Scores

(A) Mean Pediatric Hypersomnolence Survey (PHS) total score by diagnostic group. Cutoff line drawn at score of 24. (B) Mean PHS sleepiness subscale score by diagnostic group. Cutoff line drawn at score of 8. Error bars represent 1 SD. IH = idiopathic hypersomnia; NT1 = narcolepsy type 1; NT2 = narcolepsy type 2.

Figure 4. ROC Curves for Total PHS Scores

Receiver operating characteristic (ROC) curves for total Pediatric Hypersomnolence Survey (PHS) scoresfor (A) CNS hypersomnia disorders (narcolepsy or idiopathic hypersomnia [IH]), (B) narcolepsy (narcolepsy types 1 and 2), and (C) IH. (D) Sleepiness subscale score of PHS for idiopathic hypersomnia. All comparisons are made against controls and participants with other sleep disorders. AUC = area under the curve.

Figure 5. PHS Is a 14-Item Scale

Scoring is “often” = 3 points, “sometimes” = 2 points, “never” = 1 point, and “do not know” = not scored. Total score is the sum of all 14 items, and cutoff score for narcolepsy/idiopathic hypersomnia (IH) is >24. Sleepiness subscore is the sum of items 1 through 5 and 12. Cutoff score for the sleepiness subscore is >8 for IH. PHS = Pediatric Hypersomnolence Survey.