Does age at the onset of narcolepsy influence the course and severity of the disease?

Abstract 

Objective

The aim of the study is to compare the course and severity of narcolepsy in relation to different ages at the disease onset.

Methods

Clinical interviews with the completion of the Stanford questionnaire, Epworth Sleepiness Scale (ESS) and Multiple Sleep Latency Test (MSLT) were evaluated in 105 patients (44 males, 61 females, mean age 45.4±19.2, BMI 29.2±5.8) suffering from narcolepsy.

Results

The severity of the disease was judged by clinical complaints, ESS value and MSLT results. No relations with the age at onset and clinical tetrad were found, however, smoking may be associated with an increased risk of hypnagogic hallucinations. There was no correlation between the number of sleep and cataplectic attacks and the age at onset, nor did subjective ESS show any significant dependence. However, earlier onset of the disease correlated with shorter MSLT mean latency. A correlation was found between the BMI and narcolepsy sleepiness rating in the elderly and between degree of education attained and subjective complaints.

Conclusions

The clinical severity of narcolepsy does not depend on the age at onset.

Keywords: Narcolepsy, Age at onset, Course and severity, Environmental factors, Smoking, Education, Body mass index