[Analysis of clinical characteristics and risk factors in children and adolescents with narcolepsy type 1 across different severities of daytime sleepiness].

Objective: To explore the clinical and objective sleep characteristics of the severity of sleepiness in children and adolescents with narcolepsy type 1 (NT1), and to analyze the influence of nocturnal sleep parameters on excessive daytime sleepiness (EDS). Methods: This was a cross-sectional study. One hundred and fourteen children and adolescents (age <18 years) diagnosed with NT1 at the Department of Neurology, Tangdu Hospital, the Fourth Military Medical University from January 2015 to January 2025 were retrospetively included. The patients were divided into mild [mean sleep latency (MSL)>2.80 min], moderate (0.97 min<MSL≤2.80 min), and severe (MSL≤0.97 min) EDS groups according to quartiles of the (MSL on multiple sleep latency test (MSLT). Demographic data, clinical features, nocturnal polysomnography (nPSG) parameters, and MSLT parameters were compared among the three groups. Pearson correlation and Spearman rank correlation were used to analyze the correlation of MSL with mean rapid eye movement sleep latency (MRL) and with the Epworth sleepiness scale (ESS) score, respectively. Generalized linear models were used to analyze factors influencing MSL and MRL. Results: There were 28 (24.56%), 58 (50.88%) and 28 (24.56%) cases in mild, moderate, and severe EDS groups, respectively. Intergroup comparisons showed statistical differences in age of consultation (P=0.012) and the prevalence of comorbid anxiety (P=0.020) and depression (P=0.035). nPSG results revealed that sleep latency (SL) progressively shortened with increasing EDS severity, with significant differences among all three groups (all P<0.05); The proportion of N1 sleep was higher in the moderate EDS group than that in the mild group (P<0.05); The lowest nocturnal oxygen saturation was lower in the moderate and severe EDS groups than that in the mild group (all P<0.05). MSLT results indicated that MRL progressively shortened with increasing EDS severity, with significant differences among all three groups (all P<0.05); The number of sleep-onset rapid eye movement (REM) periods and the average duration of REM sleep were higher in the moderate and severe EDS groups than those in the mild group (all P<0.05); The severe EDS group showed more frequent Awake-REM transitions compared with the mild group (P<0.05). Generalized linear modeling identified shorter nocturnal SL, longer N1 sleep duration, higher arousal index, and higher periodic limb movements index as factors associated with shorter MSL (β=0.08, P<0.001; β=-0.01, P=0.022; β=-0.08, P=0.003; β=-0.27, P=0.024); Shorter nocturnal SL and shorter nocturnal REM sleep latency were factors of shorter MRL (β=1.26, P<0.001; β=0.01, P=0.019). Spearman's rank correlation coefficient showed that no significant correlation was found between Epworth sleepiness scale scores and objective MSL (ρ=-0.099, P=0.299). Conclusions: The severity of objective EDS in children and adolescents with NT1 is associated with nocturnal sleep disturbances. Therefore, in clinical practice, clinical evaluation should encompass both daytime symptoms and nocturnal sleep quality to improve overall prognosis.