Comparing symptom measurement tools in pediatric narcolepsy

Narcolepsy is a rare disabling neurological disease, affecting children and adults. The most recent development of measurement tools for narcolepsy were developed for adults; only a few tools are available for children without comparison on their validity. This research aims at comparing the validity of existing measurement tools in paediatric narcolepsy. From an ongoing randomized controlled trial, we extracted the data blind to the treatment of the 93 first terminating patients on which we compared the Paediatric Daytime Sleepiness Scale (PDSS), the Ullanlina Narcolepsy scale (UNS), the Child and Adolescent Sleepiness Questionnaire (CASS), the maintenance of wakefulness test (MWT), and the cataplexy episodes count (CEC).

The comparison was carried out on reliability, internal consistency, sensitivity to change, minimum important difference, construct validity and concurrent validity.

We provide evidence that the Ullanlina UNS score, currently used for screening purposes, constitutes a reliable and sensitive overall symptom measurement tool. Its subscore (UNS-CTP) based on the first four items permits a sensitive measurement of cataplexy, whereas the UNS-EDS subscore was found inferior to the PDSS scale. Compared with the objective measurement of symptoms (MWT, CEC), these scales better correlated with the clinical global impression of change in time, they are characterized by higher sensitivity, and they are much easier to use.