Narcolepsy Severity Scale-2 and Idiopathic Hypersomnia Severity Scale to better quantify symptoms severity and consequences in Narcolepsy type 2.

STUDY OBJECTIVES: Narcolepsy type 2 (NT2) is an understudied central disorder of hypersomnolence sharing some similarities with narcolepsy type 1 and idiopathic hypersomnia (IH). We aimed: (1) to assess systematically the symptoms in patients with NT2, with self-reported questionnaires: Epworth Sleepiness Scale (ESS), Narcolepsy Severity Scale (NSS), IH Severity Scale (IHSS), and (2) to evaluate the responsiveness of these scales to treatment. METHODS: One hundred and nine patients with NT2 (31.4 ±â€…12.2 years old, 47 untreated) diagnosed according to ICSD-3 were selected in a Reference Center for Narcolepsy. They all completed the ESS, subgroups completed the modified NSS (NSS-2, without cataplexy items) (n = 95) and IHSS (n = 76). Some patients completed the scales twice (before/during treatment): 42 ESS, 26 NSS-2, and 30 IHSS. RESULTS: Based on NSS-2, all untreated patients had sleepiness, 58% disrupted nocturnal sleep, 40% hallucinations, and 28% sleep paralysis. On IHSS, 76% reported a prolonged nocturnal sleep, and 83% sleep inertia. In the independent sample, ESS and NSS-2 scores were lower in treated patients, with same trend for IHSS scores. After treatment, ESS, NSS-2, and IHSS total scores were lower, with a mean difference of 3.7 ±â€…4.1, 5.3 ±â€…6.7, and 4.1 ±â€…6.2, respectively. The minimum clinically important difference between untreated and treated patients were 2.1 for ESS, 3.3 for NSS-2, and 3.1 for IHSS. After treatment, 61.9% of patients decreased their ESS > 2 points, 61.5% their NSS-2 > 3 points, and 53.3% their IHSS > 3 points. CONCLUSIONS: NSS-2 and IHSS correctly quantified symptoms' severity and consequences in NT2, with good performances to objectify response to medications. These tools are useful for monitoring and optimizing NT2 management, and for use in clinical trials.

Cardiovascular fitness in narcolepsy is inversely related to sleepiness and the number of cataplexy episodes.

OBJECTIVE: Cardiopulmonary fitness depends on daily energy expenditure or the amount of daily exercise. Patients with narcolepsy spent more time being sleepy or asleep than controls; thus we may speculate that they have a lower quantity and quality of physical activity. The aim of the present study was thus to test the hypothesis that exercise tolerance in narcolepsy negatively depends on sleepiness. PATIENTS AND METHODS: The cross-sectional study included 32 patients with narcolepsy with cataplexy, 10 patients with narcolepsy without cataplexy, and 36 age- and gender-matched control subjects, in whom a symptom-limited exercise stress test with expired gas analysis was performed. A linear regression analysis with multivariate models was used with stepwise variable selection. RESULTS: In narcolepsy patients, maximal oxygen uptake (VO2peak) was 30.1 ± 7.5 mL/kg/min, which was lower than 36.0 ± 7.8 mL/kg/min, p = 0.001, in controls and corresponded to 86.4% ± 20.0% of the population norm (VO2peak%) and to a standard deviation (VO2peakSD) of -1.08 ± 1.63 mL/kg/min of the population norm. VO2peak depended primarily on gender (p = 0.007) and on sleepiness (p = 0.046). VO2peak% depended on sleepiness (p = 0.028) and on age (p = 0.039). VO2peakSD depended on the number of cataplexy episodes per month (p = 0.015) and on age (p = 0.030). CONCLUSIONS: Cardiopulmonary fitness in narcolepsy and in narcolepsy without cataplexy is inversely related to the degree of sleepiness and cataplexy episode frequency.

Test-retest reliability of the multiple sleep latency test in narcolepsy without cataplexy and idiopathic hypersomnia.

STUDY OBJECTIVES: Differentiation of narcolepsy without cataplexy from idiopathic hypersomnia relies entirely upon the multiple sleep latency test (MSLT). However, the test-retest reliability for these central nervous system hypersomnias has never been determined. METHODS: Patients with narcolepsy without cataplexy, idiopathic hypersomnia, and physiologic hypersomnia who underwent two diagnostic multiple sleep latency tests were identified retrospectively. Correlations between the mean sleep latencies on the two studies were evaluated, and we probed for demographic and clinical features associated with reproducibility versus change in diagnosis. RESULTS: Thirty-six patients (58% women, mean age 34 years) were included. Inter -test interval was 4.2 ± 3.8 years (range 2.5 months to 16.9 years). Mean sleep latencies on the first and second tests were 5.5 (± 3.7 SD) and 7.3 (± 3.9) minutes, respectively, with no significant correlation (r = 0.17, p = 0.31). A change in diagnosis occurred in 53% of patients, and was accounted for by a difference in the mean sleep latency (N = 15, 42%) or the number of sleep onset REM periods (N = 11, 31%). The only feature predictive of a diagnosis change was a history of hypnagogic or hypnopompic hallucinations. CONCLUSIONS: The multiple sleep latency test demonstrates poor test-retest reliability in a clinical population of patients with central nervous system hypersomnia evaluated in a tertiary referral center. Alternative diagnostic tools are needed.

Narcolepsy with obstructive sleep apnea in a 4-year-old Korean girl: a case report.

A 4-yr-old girl has exhibited severe snoring, restless sleep and increasing daytime sleepiness over the last 3 months. The physical examination showed that she was not obese but had kissing tonsils. Polysomnography demonstrated increased apnea-hypopnea index (AHI) of 5.2, and multiple sleep latency tests (MSLT) showed shortened mean sleep latency and one sleep-onset REM period (SOREMP). She was diagnosed with obstructive sleep apnea (OSA) and underwent tonsillectomy and adenoidectomy. After the surgery, her sleep became much calmer, but she was still sleepy. Another sleep test showed normal AHI of 0.2, the mean sleep latency of 8 min, and two SOREMPs. Diagnosis of OSA to be effectively treated by surgery and narcolepsy without cataplexy was confirmed. Since young children exhibiting both OSA and narcolepsy can fail to be diagnosed with the latter, it's desirable to conduct MSLT when they have severe daytime sleepiness or fail to get better even with good treatment.

Narcolepsy with Obstructive Sleep Apnea in a 4-Year-Old Korean Girl: A Case Report

A 4-yr-old girl has exhibited severe snoring, restless sleep and increasing daytime sleepiness over the last 3 months. The physical examination showed that she was not obese but had kissing tonsils. Polysomnography demonstrated increased apnea-hypopnea index (AHI) of 5.2, and multiple sleep latency tests (MSLT) showed shortened mean sleep latency and one sleep-onset REM period (SOREMP). She was diagnosed with obstructive sleep apnea (OSA) and underwent tonsillectomy and adenoidectomy. After the surgery, her sleep became much calmer, but she was still sleepy. Another sleep test showed normal AHI of 0.2, the mean sleep latency of 8 min, and two SOREMPs. Diagnosis of OSA to be effectively treated by surgery and narcolepsy without cataplexy was confirmed. Since young children exhibiting both OSA and narcolepsy can fail to be diagnosed with the latter, it's desirable to conduct MSLT when they have severe daytime sleepiness or fail to get better even with good treatment.

Predictors of hypocretin (orexin) deficiency in narcolepsy without cataplexy.

STUDY OBJECTIVES: To compare clinical, electrophysiologic, and biologic data in narcolepsy without cataplexy with low (≤ 110 pg/ml), intermediate (110-200 pg/ml), and normal (> 200 pg/ml) concentrations of cerebrospinal fluid (CSF) hypocretin-1. SETTING: University-based sleep clinics and laboratories. PATIENTS: Narcolepsy without cataplexy (n = 171) and control patients (n = 170), all with available CSF hypocretin-1. DESIGN AND INTERVENTIONS: Retrospective comparison and receiver operating characteristics curve analysis. Patients were also recontacted to evaluate if they developed cataplexy by survival curve analysis. MEASUREMENTS AND RESULTS: The optimal cutoff of CSF hypocretin-1 for narcolepsy without cataplexy diagnosis was 200 pg/ml rather than 110 pg/ml (sensitivity 33%, specificity 99%). Forty-one patients (24%), all HLA DQB1*06:02 positive, had low concentrations (≤ 110 pg/ml) of CSF hypocretin-1. Patients with low concentrations of hypocretin-1 only differed subjectively from other groups by a higher Epworth Sleepiness Scale score and more frequent sleep paralysis. Compared with patients with normal hypocretin-1 concentration (n = 117, 68%), those with low hypocretin-1 concentration had higher HLA DQB1*06:02 frequencies, were more frequently non-Caucasians (notably African Americans), with lower age of onset, and longer duration of illness. They also had more frequently short rapid-eye movement (REM) sleep latency (≤ 15 min) during polysomnography (64% versus 23%), and shorter sleep latencies (2.7 ± 0.3 versus 4.4 ± 0.2 min) and more sleep-onset REM periods (3.6 ± 0.1 versus 2.9 ± 0.1 min) during the Multiple Sleep Latency Test (MSLT). Patients with intermediate concentrations of CSF hypocretin-1 (n = 13, 8%) had intermediate HLA DQB1*06:02 and polysomnography results, suggesting heterogeneity. Of the 127 patients we were able to recontact, survival analysis showed that almost half (48%) with low concentration of CSF hypocretin-1 had developed typical cataplexy at 26 yr after onset, whereas only 2% had done so when CSF hypocretin-1 concentration was normal. Almost all patients (87%) still complained of daytime sleepiness independent of hypocretin status. CONCLUSION: Objective (HLA typing, MSLT, and sleep studies) more than subjective (sleepiness and sleep paralysis) features predicted low concentration of CSF hypocretin-1 in patients with narcolepsy without cataplexy.