Narcolepsy in pediatric age - Experience of a tertiary pediatric hospital

Circadian rhythm of daytime sleepiness in pediatric narcolepsy: A pilot study

BACKGROUND AND OBJECTIVE

Excessive daytime sleepiness (EDS) has been far back reported as the most disabling symptom in the pediatric narcoleptic patients. However, there is a lack of studies to examine the circadian rhythms of EDS in pediatric narcoleptic population. Therefore, we aim to investigate the circadian rhythm of EDS in pediatric narcolepsy patients.

METHODS

We identified 50 pediatric narcoleptic patients (36 males and 14 females, mean age 13.68 ± 2.75 years). Data were collected through interviews and the relevant questionnaires (children depression inventory [CDI] and the pediatric quality of life inventory [PedsQL]).

RESULT

The frequencies of sleep attacks during different intervals of the day differed significantly, with higher frequency in the morning (p < .001). The times of sleep attacks in the morning and in the afternoon were significantly associated with the degree of impairment on class and the severity of worry about sleepiness, with spearman correlation coefficient ranging from .289 to .496 (p < .05). The total scores of PedsQL and CDI differed significantly among morning sleepiness dominant, afternoon sleepiness dominant, and evening sleepiness dominant groups (p = .042, p = .040). The severity scores of the narcoleptic patients' sleepiness had two peaks, one of which occurred at 16:00, and the other peaks occurred at about 11:00.

CONCLUSION

These results suggest that changes based on the circadian rhythm of sleepiness of the pediatric narcoleptic patients should be made in the treatment strategy. In addition, regulating the secretion of melatonin could serve as a promising treatment to relieve sleepiness in the future.

Validation of Multiple Sleep Latency Test for the diagnosis of pediatric narcolepsy type 1

Objective

To validate polysomnographic markers (sleep latency and sleep-onset REM periods [SOREMPs] at the Multiple Sleep Latency Test [MSLT] and nocturnal polysomnography [PSG]) for pediatric narcolepsy type 1 (NT1) against CSF hypocretin-1 (hcrt-1) deficiency and presence of cataplexy, as no criteria are currently validated in children.

Methods

Clinical, neurophysiologic, and, when available, biological data (HLA-DQB1*06:02 positivity, CSF hcrt-1 levels) of 357 consecutive children below 18 years of age evaluated for suspected narcolepsy were collected. Best MSLT cutoffs were obtained by receiver operating characteristic (ROC) curve analysis by contrasting among patients with available CSF hcrt-1 assay (n = 228) with vs without CSF hcrt-1 deficiency, and further validated in patients without available CSF hcrt-1 against cataplexy (n = 129).

Results

Patients with CSF hcrt-1 deficiency were best recognized using a mean MSLT sleep latency ≤8.2 minutes (area under the ROC curve of 0.985), or by at least 2 SOREMPs at the MSLT (area under the ROC curve of 0.975), or the combined PSG + MSLT (area under the ROC curve of 0.977). Although specificity and sensitivity of reference MSLT sleep latency ≤8 minutes and ≥2 SOREMPs (nocturnal SOREMP included) was 100% and 94.87%, the combination of MSLT sleep latency and SOREMP counts did not improve diagnostic accuracy. Age or sex also did not significantly influence these results in our pediatric population.

Conclusions

At least 2 SOREMPs or a mean sleep latency ≤8.2 minutes at the MSLT are valid and reliable markers for pediatric NT1 diagnosis, a result contrasting with adult NT1 criteria.

Classification of evidence

This study provides Class III evidence that for children with suspected narcolepsy, polysomnographic and MSLT markers accurately identify those with narcolepsy type 1.

Factors Influencing Time to Diagnosis in Childhood Narcolepsy Type 1

OBJECTIVE

To study the variables impacting on time from symptom onset to diagnosis in childhood narcolepsy, including presence of cataplexy, onset in infancy, administration of the H1N1 Pandemrix vaccine, and date of diagnosis following the H1N1 pandemic.

DESIGN

A retrospective cohort study of 42 children seen in a single tertiary pediatric neurology center between 1996 and 2016.

KEY RESULTS

Onset of symptoms of narcolepsy occurred between infancy and 15 years, with 92.9% of children symptomatic by 13 years. Time from reported symptom onset to diagnosis ranged from 3 months to 11 years, with 51.3% diagnosed within 12 months of symptom onset. Those patients who were reportedly symptomatic from birth had a statistically significant increased time from reported symptom onset to diagnosis.

CONCLUSIONS

The symptoms of childhood narcolepsy progress over time. The number of annual diagnoses in this center increased over the study period, but there is no evidence that the time from symptom onset to diagnosis is decreasing. Being reportedly symptomatic from the age of <1 year is associated with an increased time to diagnosis. We recommend raising awareness of narcolepsy among medical students and general practitioners. It is important that clinicians appreciate the clinical relevance of excessive daytime sleepiness.

The multiple sleep latency test

The measurement of daytime sleepiness is important in the evaluation of patients with excessive sleepiness. The multiple sleep latency test (MSLT) is an objective test that measures the tendency to fall asleep under controlled conditions. It is based on the notion that sleep latency reflects underlying physiological sleepiness. The MSLT consists of four to five naps given 2h apart during the day, following a standardized procedure. The mean sleep latency from all naps is used as the measure of sleepiness. The test has been shown to be valid and reliable and is part of the diagnostic criteria for narcolepsy and idiopathic hypersomnia. However, the MSLT is affected by numerous variables including insufficient sleep, drugs, activity, and arousal level. Adherence to the established protocol is necessary to limit the effect of these extraneous factors on the MSLT. While the test is a valuable and widely used diagnostic tool for narcolepsy and idiopathic hypersomnia, the use of MSLT in other sleep disorders is not well established.

Associations Between Neuropsychological, Neurobehavioral and Emotional Functioning and Either Narcolepsy or Idiopathic Hypersomnia in Children and Adolescents

STUDY OBJECTIVES

Narcolepsy and idiopathic hypersomnia are chronic neurological sleep disorders characterized by hypersomnolence or excessive daytime sleepiness. This review aims to systematically examine the scientific literature on the associations between narcolepsy and idiopathic hypersomnia and their effect on intellectual functioning, academic achievement, behavior, and emotion.

METHODS

Published studies that examined those associations in children and adolescents were included. Studies in which children or adolescents received a clinical diagnosis, and in which the associated function was measured with at least one objective instrument were included. Twenty studies published between 1968 and 2017 were eligible for inclusion in this review.

RESULTS

There does not appear to be a clear association between intellectual functioning and narcolepsy or idiopathic hypersomnia; however, limited research is an obstacle to obtaining generalizability. The variability in results from studies investigating associations between academic achievement and these two hypersomnolence disorders suggests that further research using standardized and validated assessment instruments is required to determine if there is an association. Behavior and emotion appear to be significantly affected by narcolepsy. Only two studies included populations of children and adolescents with idiopathic hypersomnia.

CONCLUSIONS

Further research using larger populations of children and adolescents with narcolepsy or idiopathic hypersomnia while utilizing standardized and validated instruments is required, because the effect of these conditions of hypersomnolence varies and is significant for each individual.