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OBJECTIVE To determine whether brain amyloid burden in elderly patients with narcolepsy type 1 (NT1) is lower than in controls, and to assess in patients with NT1 the relationships between amyloid burden, cerebral spinal fluid (CSF) markers of Alzheimer disease (AD), CSF orexin-A, and cognitive profile. METHODS Cognitive and 18 F-florbetapir positron emission tomography (PET) data were compared in patients with NT1 aged ≥ 65 years (n = 23) and in age- and sex-matched controls free of clinical dementia selected from the Alzheimer's Disease Neuroimaging Initiative (ADNI; n = 69) and the Multi-Domain Intervention Alzheimer's Prevention Trial (MAPT-18F AV45-PET; n = 23) cohorts. The standardized uptake values (SUVs) of the cortical retention index for 6 regions of interest were computed and averaged to create a mean SUV ratio normalized to 3 subcortical reference regions (cerebellum, pons, and a composite region). A cortical/cerebellum SUV ratio ≥ 1.17 defined positive PET amyloid. RESULTS Lower cortical amyloid burden was observed in the NT1 than in the ADNI and MAPT-AV45 groups (mean cortical/cerebellum SUV ratios = 0.95 ± 0.15, 1.11 ± 0.18 [p

Objective To assess the diagnostic value of extended sleep duration on a controlled 32-hour bed rest protocol in idiopathic hypersomnia (IH). Methods One hundred sixteen patients with high suspicion of IH (37 clear-cut IH according to multiple sleep latency test criteria and 79 probable IH), 32 with hypersomnolence associated with a comorbid disorder (non-IH), and 21 controls underwent polysomnography, modified sleep latency tests, and a 32-hour bed rest protocol. Receiver operating characteristic curves were used to find optimal total sleep time (TST) cutoff values on various periods that discriminate patients from controls. Results TST was longer in patients with clear-cut IH than other groups (probable IH, non-IH, and controls) and in patients with probable IH than non-IH and controls. The TST cutoff best discriminating clear-cut IH and controls was 19 hours for the 32-hour recording (sensitivity = 91.9%, specificity = 85.7%) and 12 hours (100%, 85.7%) for the first 24 hours. The 19-hour cutoff displayed a specificity and sensitivity of 91.9% and 81.2% between IH and non-IH patients. Patients with IH above the 19-hour cutoff were overweight, had more sleep inertia, and had higher TST on all periods compared to patients below 19 hours, whereas no differences were found for the 12-hour cutoff. An inverse correlation was found between the mean sleep latency and TST during 32-hour recording in IH patients. Interpretation In standardized and controlled stringent conditions, the optimal cutoff best discriminating patients from controls was 19 hours over 32 hours, allowing a clear-cut phenotypical characterization of major interest for research purposes. Sleepier patients on the multiple sleep latency test were also the more severe in terms of extended sleep. Ann Neurol 2018;83:235-247.

Objective To assess video-polysomnographic (vPSG) criteria and their cutoff values for the diagnosis of disorders of arousal (DOAs; sleepwalking, sleep terror). Methods One hundred sixty adult patients with DOAs and 50 sex- and age-matched healthy participants underwent a clinical evaluation and vPSG assessment to quantify slow wave sleep (SWS) interruptions (SWS fragmentation index, slow/mixed and fast arousal ratios, and indexes per hour) and the associated behaviors. First, a case-control analysis was performed in 100 patients and the 50 controls to define the optimal cutoff values using receiver operating characteristic curves. Their sensitivity was then assessed in the other 60 patients with DOAs. Results The SWS fragmentation index and the mixed, slow, and slow/mixed arousal indexes and ratios were higher in patients with DOAs than controls. The highest area under the curve (AUC) values were obtained for the SWS fragmentation and slow/mixed arousal indexes (AUC = 0.88 and 0.90, respectively). The SWS fragmentation index cutoff value of 6.8/h reached a sensitivity of 79% and a specificity of 82%. The slow/mixed arousal index had a sensitivity of 94% for the 2.5/h cutoff, and 100% specificity for 6/h. Both parameters showed good interrater agreement, and their sensitivities were confirmed in the second group of patients. Combining electroencephalographic parameters and video-based behavioral analyses increased the correct classification rate up to 91.3%. Interpretation Frequent slow/mixed arousals in SWS and complex behaviors during vPSG are strongly associated with DOAs, and could be promising biomarkers for the diagnosis of non-rapid eye movement parasomnias. Ann Neurol 2018;83:341-351.

Objective: The pathophysiology of idiopathic hypersomnia (IH) remains unclear. Recently, cerebrospinal fluid (CSF)-induced enhancement of c-aminobutyric acid (GABA)-A receptor activity was found in patients with IH compared to controls. Methods: Fifteen unrelated patients (2 males and 13 females) affected with typical IH, 12 patients (9 males and 3 females) with narcolepsy type 1, and 15 controls (9 males and 6 females) with unspecified hypersomnolence (n 5 7) and miscellaneous neurological conditions (n 5 8) were included. A lumbar puncture was performed in all participants to measure CSF hypocretin-1 and GABA-A response. We used a voltage-clamp assay on Xenopus oocytes injected with the RNAs that encode the a 1 b 2 c 2 or the a 2 b 2 c 2 subunits of the human GABA-A receptor. A sequence of 6 different applications (GABA, GABA/CSF, and CSF alone) with 2 to 4 oocytes per CSF sample was performed in a whole-cell voltage-clamp assay. Results: Representative current traces from oocytes expressing human a 1 b 2 c 2 or a 2 b 2 c 2 GABA-A receptors were recorded in response to 6 successive puffs of GABA diluted in the survival medium (SM), showing stable and reliable response. GABA puffs diluted in SM/CSF solution or SM/CSF solution alone showed no significant differences in the CSF of IH, narcolepsy, or control groups. No associations were found between GABA responses, demographic features , disease duration, or disease severity in the whole population or within groups. Interpretation: Using the Xenopus oocyte assay, we found an absence of GABA-A receptor potentiation with CSF from patients with central hypersomnolence disorders, with no significant differences between hypocretin-deficient and non–hypocretin-deficient patients compared to controls. ANN NEUROL 2016;80:259–268 I diopathic hypersomnia (IH) is an orphan sleep disorder , clinically characterized by excessive daytime sleepi-ness (EDS) with long and unrefreshing naps, prolonged and undisturbed nocturnal sleep, and great difficulty waking up after sleep, called sleep inertia. 1 The main features of IH are normal nighttime sleep with high sleep efficiency and high percentage of deep (slow wave) non– rapid eye movement (NREM) sleep on polysomnography (PSG), with either decreased mean sleep latencies with