An Alternative to the Multiple Sleep Latency Test for Determining Sleepiness in Narcolepsy and Hypersomnia: Polygraphic Score of Sleepiness

Abstract

This article describes a quantitative assessment of pathological diurnal sleepiness in three groups of patients with excessive daytime sleepiness: narcoleptic patients, idiopathic hypersomniac patients, hypersomniac patients with sleep apnea syndrome. We analyzed polygraphic diurnal recordings of 45 min duration obtained under standardized conditions. We called the percentage of total sleep time during the 45-min recording the polygraphic index of sleepiness. The polygraphic score of sleepiness is determined by the latencies and total durations of the individual sleep stages. Because deeper sleep stages correspond to more pronounced sleepiness than do superficial sleep stages, we introduced coefficients for each sleep stage. We present a formula for calculating a score in a single figure that gives a good indication of the patient's sleepiness and makes inter- and intraindividual comparison possible. Separate REM and NREM sleep scores are also given.