Narcolepsy is a central hypersomnolence disorder characterized by excessive daytime sleepiness, cataplexy (specific to type 1), hypnagogic/hypnopompic hallucinations, sleep paralysis, and disrupted nighttime sleep. Evidence suggests that symptom onset occurs sometimes in childhood and most frequently during adolescence. The prevalence of pediatric narcolepsy has been estimated at 10.0 per 100,000 in the United States; however, pediatric narcolepsy can be difficult to diagnose and often goes undetected or misdiagnosed for many years. Such diagnostic delays can hinder patient access to proper care, with negative consequences.
In the need of a better screening tool a recent study by Morris and collaborators (1) evaluated the psychometric properties of the Pediatric Narcolepsy Screening Questionnaire (PNSQ), developed in response to the difficulty of identifying pediatric narcolepsy.
The initial PNSQ was updated following debriefing interviews with parents of children with suspected/diagnosed narcolepsy. Subsequently, newly recruited caregivers were categorized into groups: clinician-confirmed narcolepsy, other sleep problems (OSP), and no sleep problems (controls). Caregivers completed the 11-item PNSQ assessing narcolepsy symptomatology. PNSQ psychometric properties were evaluated; mean PNSQ Total Score (TS) was compared inter-group using analysis of variance.
The analysis population (N = 158) included patients with narcolepsy (n = 49), OSP (n = 55), and controls (n = 54); mean ± SD age was 13.8 ± 2.8, 10.2 ± 4.3, and 10.0 ± 3.8 years, respectively. Inter-item Pearson correlations (range, 0.22-0.75) indicated good construct validity. Principal component analysis confirmed unidimensionality. Item discriminative power was high for narcolepsy vs control (range, 0.693-0.936) and lower for narcolepsy vs OSP (range, 0.584-0.729). The latent trait was well covered (separation index = 0.868). Item 7 (vivid dreams/nightmares), having low discriminative power and specificity, was removed. Cronbach's alpha (final PNSQ) indicated high internal consistency reliability (raw alpha = 0.88). Mean ± SD PNSQ TS (range, 0-50) in the narcolepsy, OSP, and control groups were 34.98 ± 7.98, 25.20 ± 9.43, and 9.54 ± 9.38, respectively (nominal P < 0.0001). Classification by PNSQ TS was defined: PNSQ+ (likely narcolepsy, TS ≥ 29), PNSQ 0 (likely OSP, TS 19-28), and PNSQ- (narcolepsy unlikely, TS ≤ 18).
In conclusion the PNSQ demonstrated good psychometric properties and excellent performance discriminating narcolepsy, OSP, and control groups.
Key Points:
- Pediatric narcolepsy often goes undetected or misdiagnosed for many years, with negative consequences on patients.
- In the need of a tool for screening the psychometric proprieties of Pediatric Narcolepsy Screening Questionnaire (PNSQ) were evaluated and the tool was validated.
- After a correction of the tool, including elimination of one question and resetting of cut-offs the PNSQ can be used as a reliable and efficient tool for the early detection of pediatric narcolepsy.
References:
- Morris S, Plazzi G, de la Loge C, Marrel A, Profant J, Steininger TL, Lin J, Owens JA. Validation of the Pediatric Narcolepsy Screening Questionnaire (PNSQ): A cross-sectional, observational study. Sleep Med. 2022 Oct;98:127-138.
- Vignatelli L, Antelmi E, Ceretelli I, Bellini M, Carta C, Cortelli P, Ferini-Strambi L, Ferri R, Guerrini R, Ingravallo F, Marchiani V, Mari F, Pieroni G, Pizza F, Verga MC, Verrillo E, Taruscio D, Plazzi G. Red Flags for early referral of people with symptoms suggestive of narcolepsy: a report from a national multidisciplinary panel. Neurol Sci. 2019 Mar;40(3):447-456.
- Postiglione E, Antelmi E, Pizza F, Lecendreux M, Dauvilliers Y, Plazzi G. The clinical spectrum of childhood narcolepsy. Sleep Med Rev. 2018 Apr;38:70-85
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