Kleine-Levin syndrome. Clinical boarderlands based on a thorough analysis of 475 case reports.

OBJECTIVE/BACKGROUND: Kleine-Levin syndrome (KLS) is a rare sleep disorder characterized by recurrent episodes of severe hypersomnolence in association with various degrees of cognitive impairment, perceptive abnormalities, apathy, behavioral disturbances. Some of these symptoms, hypersomnolence, compulsive eating and increased sexual drive may be replaced by their opposites or alternate with them. Remarkably enough, these « atypical symptoms ¼ have never been enlighted nor compared in frequency with corresponding typical symptoms. Besides, KLS is more frequent in males than in females but no review has ever compared the frequency of precipitating factors and symptoms in males and females. PATIENTS/METHODS: To uncover these as yet uninvestigated aspects of KLS, a predesigned template was used to extract precipitating factors and symptoms, in 475 case reports of KLS, comprising 364 males and 111 females. RESULTS: Precipitating factors were more frequently recorded in males (67.31 %) than in females (49.55 %). Recurrent episodes of hypersomnolencee were present in 94.32 % of cases, recurrent insomnia in 1.05 % and alternation of hypersomnolence and insomnia in 4.63 %. Cognitive impairment was present in 67.37 % of cases and absent in 6.95 %. Derealization/altered perception was present in 38.32 % of cases and absent in 1.68 %. Severe apathy was present in 44.63 % of cases. Compulsive eating was present in 59.58 % of cases, absent in 13.26 %, replaced by anorexia in 9.05 %, alternation of compulsive eating and anorexia in 5.68 % and alternation of compulsive eating and no compulsive eating in 8.42 %. Increased sexual drive was present in 33.68 % of cases, absent in 22.74 %, replaced by decreased sexual drive in 1.47 %, alternation of increased sexual drive and no increased sexual drive in 2.95 %. Odd behaviors were present in 45.05 % of cases. Psychiatric features were present in 71.58 % of cases, absent in 2.95 %. Finally, the percentages of precipitating factors and of sleep disorder, apathy, sexual disorder, irritability/agressivity, were higher in males than in females. CONCLUSIONS: The frequency of the opposites of hypersomnolence, compulsive eating and increased sexual drive appears to be quite significant. In addition, a systematic comparison of precipitating factors and symptoms in males and females has shown limited differences between sexes.

PET Study of Microglial Activation in Kleine-Levin Syndrome.

OBJECTIVES: Kleine-Levin syndrome (KLS) is a rare recurrent hypersomnolence disorder associated with cognitive and behavioral disturbances, of unknown origin, but inflammatory mechanisms could be involved. We aimed to explore in vivo microglia activation using [18F]DPA-714 PET imaging in patients with KLS compared with controls, and during symptomatic vs asymptomatic periods. METHODS: Patients with KLS and controls underwent a standardized clinical evaluation and PET imaging, using a radiolabeled ligand specific to the 18 kDa translocator protein. Images were processed on the PMOD (peripheral module) interface using a standard uptake value (SUV). Five regions of interest (ROIs) were analyzed: hypothalamus, thalamus, frontal area, cerebellum, and whole brain. SUV ratios (SUVr) were calculated by normalizing SUV with cerebellum uptake. RESULTS: Images of 17 consecutive patients with KLS (7 during episodes, 10 out of episodes) and 14 controls were analyzed. We found no SUV/SUVr difference between KLS and controls, between patients in and out episodes in all ROIs, and no correlation between SUVr and episode duration at the time of PET scan. No association was found between SUVr and sex, disease duration, or orexin levels. DISCUSSION: Our findings do not support the presence of neuroinflammation in KLS. Further research is needed to identify relevant biomarkers in KLS.

Microglia Density and Its Association With Disease Duration, Severity, and Orexin Levels in Patients With Narcolepsy Type 1.

BACKGROUND AND OBJECTIVES: Narcolepsy type 1 (NT1) is due to the loss of hypothalamic neurons that produce orexin (ORX), by a suspected immune-mediated process. Rare postmortem studies are available and failed to detect any inflammation in the hypothalamic region, but these brains were collected years after the first symptoms. In vivo studies close to disease onset are lacking. We aimed to explore microglia density in the hypothalamus and thalamus in NT1 compared with controls using [18F]DPA-714 PET and to study in NT1 the relationships between microglia density in the hypothalamus and in other regions of interest (ROIs) with disease duration, severity, and ORX levels. METHODS: Patients with NT1 and controls underwent a standardized clinical evaluation and [18F]DPA-714 PET imaging using a radiolabeled ligand specific to the 18 kDa translocator protein (TSPO). TSPO genotyping determined receptor affinity. Images were processed on peripheral module interface using standard uptake value (SUV) on ROIs: hypothalamus, thalamus, frontal area, cerebellum, and the whole brain. SUV ratios (SUVr) were calculated by normalizing SUV with cerebellum uptake. RESULTS: A total of 41 patients with NT1 (21 adults, 20 children, 10 with recent disease onset <1 year) and 35 controls were included, with no significant difference between groups for [18F]DPA-714 binding (SUV/SUVr) in the hypothalamus and thalamus. Unexpectedly, significantly lower SUVr in the whole brain was found in NT1 compared with controls (0.97 ± 0.06 vs 1.08 ± 0.22, p = 0.04). The same finding between NT1 and controls in the whole brain was observed in those with high or mixed TSPO affinity (p = 0.03 and p = 0.04). Similar trend was observed in the frontal area in NT1 (0.96 ± 0.09 vs 1.09 ± 0.25, p = 0.05). In NT1, no association was found between SUVr in different ROIs and age, disease duration, severity, or ORX levels. DISCUSSION: We found no evidence of in vivo increased microglia density in NT1 compared with controls, even close to disease onset, and even unexpectedly a decrease in the whole brain of these patients. These findings do not support the presence of neuroinflammation in the destruction process of ORX neurons. TRIAL REGISTRATION INFORMATION: ClinicalTrials.org NCT03754348.

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.