Idiopathic hypersomnia years after the diagnosis.

Little attention has been paid to the long-term development of idiopathic hypersomnia symptoms and idiopathic hypersomnia comorbidities. The aim of this study was to describe the general health of patients with idiopathic hypersomnia years after the initial diagnosis, focusing on current subjective hypersomnolence and the presence of its other possible causes. Adult patients diagnosed with idiopathic hypersomnia ≥ 3 years ago at sleep centres in Prague and Kosice were invited to participate in this study. A total of 60 patients were examined (age 47.3 ± SD = 13.2 years, 66.7% women). In all participants, their hypersomnolence could not be explained by any other cause but idiopathic hypersomnia at the time of diagnosis. The mean duration of follow-up was 9.8 + 8.0 years. Fifty patients (83%) reported persisting hypersomnolence, but only 33 (55%) had no other disease that could also explain the patient's excessive daytime sleepiness and/or prolonged sleep. In two patients (3%), the diagnosis in the meantime had changed to narcolepsy type 2, and 15 patients (25%) had developed a disease or diseases potentially causing hypersomnolence since the initial diagnosis. Complete hypersomnolence resolution without stimulant treatment lasting longer than 6 months was reported by 10 patients (17%). To conclude, in a longer interval from the diagnosis of idiopathic hypersomnia, hypersomnolence may disappear or may theoretically be explained by another newly developed disease, or the diagnosis may be changed to narcolepsy type 2. Thus, after 9.8 years, only 55% of the examined patients with idiopathic hypersomnia had a typical clinical picture of idiopathic hypersomnia without doubts about the cause of the current hypersomnolence.

Heart Rate Variability in evaluation of autonomic dysfunction in idiopathic REM-sleep behaviour disorder.

INTRODUCTION: Nearly 80% of people diagnosed with idiopathic REM sleep behaviour disorder (iRBD) via video-polysomnography (v-PSG) are expected to be in the prodromal stage of an alpha-synucleinopathy. Signs of autonomic dysfunction can appear earlier than motor or cognitive alpha-synucleinopathy symptoms. Heart Rate Variability (HRV) can potentially be an objective measurement of autonomic dysfunction, and furthermore can be obtained directly from v-PSG. OBJECTIVES: The aim of this study was to evaluate dysautonomia in iRBD subjects using HRV obtained during different sleep stages and wakefulness from v-PSG. MATERIAL AND METHODS: Subjects positively screened by an RBD screening questionnaire (RBD-SQ) underwent v-PSG to diagnose RBD. HRV obtained from v-PSG recordings was correlated to dysautonomia evaluated from a Non-Motor Symptoms Scale (NMSS) questionnaire. Optimal cut-off values of HRV parameters to predict dysautonomia were calculated using receiver operating characteristics (ROC) - area under the curve (AUC) analysis. The effect of confounder variables was predicted with binomial logistic regression and multiple regression analyses. RESULTS: Out of 72 positively screened subjects, 29 subjects were diagnosed as iRBD (mean age 66 ± 7.7 years) by v-PSG. Eighty-three per cent of the iRBD subjects in our cohort were at the time of diagnosis classified as having possible or probable prodromal Parkinson's Disease (pPD) compared to zero subjects being positively screened in the control group. The iRBD-positive subjects showed significant inverse correlations of NMSS score, particularly to log low-frequency (LF) component of HRV during wakefulness: r = -0.59 (p = 0.001). Based on ROC analysis and correlation between NMSS score, log LF during wakefulness (AUC 0.74, cut-off 4.69, sensitivity 91.7%, specificity 64.7%, p = 0.028) was considered as the most accurate predictor of dysautonomia in the iRBD group. Apnoea-hypopnoea index (AHI) negatively predicted dysautonomia in the iRBD group. None of the HRV components was able to predict the presence of iRBD in the full cohort. Age, gender, and PSG variables were significant confounders of HRV prediction. CONCLUSIONS: The presented study did not confirm the possibility of using HRV from v-PSG records of patients with iRBD to predict dysautonomia expressed by questionnaire methods. This is probably due to several confounding factors capable of influencing HRV in such a cohort.

Steroid responsive encephalopathy associated with autoimmune thyroiditis as a cause of acuteencephalopathy.

Steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT), known as Hashimoto's encephalopathy (HE), represents a heterogeneous group of neurological and neuropsychiatric symptoms associated with a presence of antithyroid antibodies in case of other causes of encephalopathy were excluded. Clinical symptoms most commonly includes acute onset of encephalopathy, behaviour changes and cognitive dysfunction, epileptic seizures as well as cerebellar and extrapyramidal symptoms. Corticoids provides rapid and sustained therapeutic benefit in most patients and only a few patients require other immunosuppressive therapy such as plasmapheresis, intravenous immunoglobulins, or others. We present the cases of two patients with acute onset of encephalopathy, status epilepticus based on SREAT, with rapid improvement after steroid treatment.

Homocysteine Is a Marker of Increased Cardio-Cerebrovascular Disease Risk in Psoriatic Patients, but It Does Not Reflect the Effect of Biological Therapy in the Longitudinal Observation.

Background: Psoriasis is linked to atherosclerosis. Homocysteine (HCYS) has been identified as a marker of increased risk of cardio-cerebrovascular diseases (CCVD) in population. Objective: The aim of the study was to determine whether elevated HCYS serves as a marker of increased CCVD in psoriasis and whether biological therapy for long-term monitoring influences HCYS levels. Methods: Clinical data, laboratory tests, and comorbid diagnoses were summarized for the two groups of patients based on entrance HCYS levels. Patients (n = 76) were included in the follow-up gradually over a period of 5 years. Results: The psoriatic patients with normal (54%) and elevated (46%) HCYS before biological treatment did not vary in clinical data, laboratory tests, treatment, and comorbid diagnoses apart from CCVD. Elevated HCYS group showed a four-fold excess of CCVD (OR 4.2, 95%CI 1.21-4.86, p=0.024). HCYS levels in the longitudinal observation did not vary. Conclusion: An increased CCVD risk, independent of other risk factors, is present in psoriatic patients with elevated HCYS. The HCYS level was not influenced by biological therapy in longitudinal observation. Further studies are needed to explore if elevated HCYS could serve as a marker of increased CCVD in any stage of psoriasis and if it should be included in classical screening strategies.

Association of seroprevalence and risk factors in Lyme disease.

OBJECTIVE: The aim of the presented cross-sectional seroepidemiological study was to determine the current presence of antibodies against B. burgdorferi s.l. in the groups of Slovak population, and to identify potential risk factors to Lyme borreliosis. METHODS: A group of 261 adults (patients from the Neurological Clinic with possible symptoms of LB and healthy persons with possible working exposure to tick bite: gardeners and soldiers working in afforested areas) were examined in order to assess the seroprevalence of anti-Borrelia antibodies. Sera were screened by commercial enzyme-linked immunosorbent assay (ELISA). The respondents completed questionnaires with general demographic, epidemiological and clinical data. RESULTS: We detected 17.2% presence of positive IgG and 5.7% presence of positive IgM antibodies in all investigated groups. Our results confirmed that the following risk factors such as age and gender are significantly associated with the presence of positive specific antibodies against investigated disease. CONCLUSION: The results of seroprevalence obtained in the present study confirm the possibility of infection with B. burgdorferi among respondents exposed to contact with ticks.

Creutzfeldt-Jakob disease surveillance in Eastern Slovakia from 2004 to 2016.

OBJECTIVES: An extraordinary incidence of genetic Creutzfeldt-Jakob disease (gCJD) appearing in clusters in the Slovak Republic was described in the 1990's. The aim of the study was to analyse data of CJD cases obtained from surveillance in Eastern Slovakia (ES) (2004-2016), the region outside the described geographical clusters. METHODS: The database set in the project was the source for epidemiological and clinical analysis of CJD cases. RESULTS: The incidence of CJD in ES (2004-2016) was 1.7/million person-years (95% CI 1-2.4); the incidence increase in the last five years (2012-2016) was comparable to the whole country. Twenty seven of 29 reported CJD cases were available for analysis (mean age 59 years, F/M 15/12). The proportion of gCJD (E200K mutation) cases remained dominant (78%), with 9 familiar cases originating in 4 families. Analysis of the clinical features revealed shorter duration of the symptomatic phase in sporadic CJD (sCJD) (3.4 months) versus gCJD (5.15 months). Cognitive/behavioural changes, insomnia, and sensory disturbance were more pronounced in the early symptoms of gCJD. Periodic EEG discharges were more frequent in sCJD (83%) than gCJD (56%), all 19 available MR findings were CJD specific and localisation of abnormalities varied amongst the CJD forms. CONCLUSIONS: The surveillance of CJD in ES (2004-2016) showed an increased incidence of CJD in ES, reaching the incidence rate of the whole country, with a permanent proportion of 70% gCJD cases based on the E200K mutation. Clinical, electrophysiological and MR features of sCJD and gCJD cases were in conformity with already published data. Epidemiological analysis of CJD in ES shows increasing detection of CJD but also suggests that current routine surveillance systems for CJD may underestimate the true burden of disease, especially sporadic cases in Slovakia.

EU questionnaire to screen for obstructive sleep apnoea validated in Slovakia.

OBJECTIVE: Obstructive sleep apnoea syndrome (OSAS) associated with daytime sleepiness (DS) contributes to a higher incidence of motor vehicle accidents. Validation of fitness to drive in driving license applicants, with special concern regarding OSAS accompanied by excessive DS, became mandatory under new EU legislation in January 2016. The aim of the study was to translate and validate the recommended questionnaire to screen for OSAS (Q-OSAS) in the Slovak population. No data on any Q-OSAS validation has previously been published. METHODS: The translated Q-OSAS was administered to 311 Slovak patients prior to a planned overnight polysomnography. The diagnostic accuracy of the Q-OSAS in OSAS with an apnoea-hypopnoea index of 15 or more/h of sleep was evaluated by calculating the area under the ROC curve. RESULTS: The sensitivity and specificity of the cut-off at 10 points for the Q-OSAS was 57% and 67%, respectively, with an increase of sensitivity and a decrease of specificity with a lowering of the cut-off values. Excluding the Epworth Sleepiness Scale (ESS) score from the final statistics yielded the best sensitivity (77%), specificity (50%), and an area under the ROC curve (0.637) for the cut-off value of 8 points (an equivalent of 10 points with the full version of the Q-OSAS). CONCLUSION: The Q-OSAS is an appropriate screening tool to facilitate the screening of subjects potentially at risk from moderate and severe OSAS. A modified two-step interpretation of the Q-OSAS in Slovakia yielded the best sensitivity, and in the future could promote evaluation of sleepiness in sleep and wake disorders other than OSAS for fitness to drive.

Serostatus and risk factors of tick-borne encephalitis.

OBJECTIVE: The aim of this seroepidemiological study was to determine the current prevalence of antibodies against tick-borne encephalitis virus (TBEV) in the representative group of Slovak population with included potential risk factors for TBEV. METHODS: Representative group consisted of 428 persons (also with possible exposure to risk factors for tick bite or raw milk consumption). Serum samples were screened by commercial enzyme-linked immunosorbent assay (ELISA). The persons involved in the study completed questionnaires with general demographic, epidemiological and clinical data. During the analysis, we used linear regression to interpret the influence between selected variables. RESULTS: We detected 1.2% prevalence of positive IgG and 1.6% prevalence of positive IgM antibodies in all tested groups. Our results also confirmed that the following risk factors such as tourism, hunting, fishing, and consumption of raw milk are significantly associated with the prevalence of specific antibodies against TBEV. CONCLUSION: The results of seroprevalence obtained by this study confirm the possibility of infection with TBEV among respondents exposed to possible contact with ticks.

West Nile virus - a new infection in the Slovak Republic?

OBJECTIVE: The aim of the study was to evaluate the seroprevalence of West Nile virus (WNV) among the variable population of Eastern Slovakia. METHODS: A serologic survey was conducted using 464 serum samples. The basic demographic, epidemiologic and clinical information was obtained for each serum sample at the time of specimen collection. The presence of antibodies against WNV was investigated using a commercial enzyme-linked immunosorbent assay (ELISA). All the ELISA positive samples were further analysed by a neutralization test with WNV and Usutu virus. RESULTS: Three serum samples (0.65%) from the participants (N = 464) were considered positive for antibodies to WNV. A 29-year-old female was repeatedly exposed to mosquito bites working as a shepherdess and participating in many outdoor activities. Two other females (61 and 76 years old) were treated at the Department of Neurology due to monoparesis of the upper extremity, vertigo; both had a significant epidemiological history with frequent tick and mosquito bites and stay in an endemic region. CONCLUSIONS: Although there was no evidence of WNV infection in the Slovak Republic, the epidemiological situation in the neighbouring countries warrants vigilance and appropriate measures, including the introduction of specific diagnostic tools into clinical practice. The constant monitoring of birds and mosquitoes also seems necessary.

Seroprevalence of Lyme disease in Eastern Slovakia.

OBJECTIVE: Lyme disease (LD) is chronic, multi-system zoonosis transmitted by ticks, and LD aetiological agents are spirochetes of the Borrelia burgdorferi sensu lato complex. The aim of the cross-sectional study was to analyze the LD incidence on the basis of the presence of specific antibodies in the serum of patients in Eastern Slovakia, and to compare the results of serological ELISA and immunoblot assays. METHODS: Venous blood with questionnaires was obtained by field sampling of respondents from Eastern Slovakia. Overall, we examined 537 human sera by the ELISA and for confirmation we tested all positive IgG antibodies against the Borrelia immunoblot assay. RESULTS: Our results confirmed the high serum prevalence of anti-Borrelia antibodies (17.9% for IgG), while the immunoblot seropositive test was confirmed in 69.8% of responders from ELISA IgG positive sera. Positive antibodies of the IgM class were found in 7.6% of the population under study. Most commonly found were antibodies against VlsE (80.2%), p41 (66.7%), p18 (56.3%), p100 (41.7%), p58 (31.3%), and p39 (30.2%). CONCLUSION: It should be noted that detection of antibodies against B. burgdorferi s.l. is only an indirect evidence of the presence of this bacterium in the development of clinical signs of LD in humans. Laboratory LD tests should be performed in accordance with valid standards, positive and uncertain results must be confirmed by the Western Blot/Immunoblot assay.

The European Narcolepsy Network (EU-NN) database.

Narcolepsy with cataplexy is a rare disease with an estimated prevalence of 0.02% in European populations. Narcolepsy shares many features of rare disorders, in particular the lack of awareness of the disease with serious consequences for healthcare supply. Similar to other rare diseases, only a few European countries have registered narcolepsy cases in databases of the International Classification of Diseases or in registries of the European health authorities. A promising approach to identify disease-specific adverse health effects and needs in healthcare delivery in the field of rare diseases is to establish a distributed expert network. A first and important step is to create a database that allows collection, storage and dissemination of data on narcolepsy in a comprehensive and systematic way. Here, the first prospective web-based European narcolepsy database hosted by the European Narcolepsy Network is introduced. The database structure, standardization of data acquisition and quality control procedures are described, and an overview provided of the first 1079 patients from 18 European specialized centres. Due to its standardization this continuously increasing data pool is most promising to provide a better insight into many unsolved aspects of narcolepsy and related disorders, including clear phenotype characterization of subtypes of narcolepsy, more precise epidemiological data and knowledge on the natural history of narcolepsy, expectations about treatment effects, identification of post-marketing medication side-effects, and will contribute to improve clinical trial designs and provide facilities to further develop phase III trials.

Smoking Prevalence and Its Clinical Correlations in Patients with Narcolepsy-cataplexy.

Narcolepsy-cataplexy (NC) is a chronic neurological disease with suggested autoimmune etiopathogenesis. Nicotine stimulates central nervous system and smoking increases the risk of autoimmune diseases. Assessment of smoking habits and its correlation to clinical parameters among 87 adult NC patients (38 male, 49 female) included night polysomnography and multiple sleep latency test. In our sample, 43.7% NC patients were regular smokers, and 19.5% former smokers compared to 22.2%, and 12.6%, respectively, in the general population. Patients started to smoke in the mean age of 20.0 (SD ±6.0) years. 72.2% of NC smokers started to smoke before the onset of NC and the mean of the delay between smoking onset and NC onset was 9.1 (±5.8) years. We found a direct correlation between smoking duration and the number of awakenings, duration of N1 sleep, REM sleep latency, and apnoea/hypopnoea index (AHI), and, on the contrary, indirect correlation between smoking duration and N3 sleep duration, showing that smoking duration consistently correlates with sleep macrostructure. Smoking is highly prevalent in NC and has relationship with clinical features of NC.

α-synuclein antibody 5G4 identifies idiopathic REM-sleep behavior disorder in abdominal skin biopsies.

INTRODUCTION: Idiopathic REM-sleep behavior disorder (iRBD) is considered the most specific prodromal marker of Parkinson's disease (PD). With the need to improve early detection of prodromal α-synucleinopathies, several methods to identify peripheral α-synuclein (α-syn) pathology have been exploited in manifest and prodromal PD with varying diagnostic accuracy. Recently, a disease specific 5G4 antibody has been evaluated in skin biopsies of manifest PD patients. The aim of our study was to analyze the 5G4 α-syn immunoreactivity in skin biopsies of deeply phenotyped subjects with iRBD and controls. METHODS: The study cohort consisted of 28 patients with PD, 24 subjects with iRBD and 27 healthy controls, recruited from the CEGEMOD, PDBIOM and PARCAS cohorts. All subjects were deeply phenotyped and assessed for prodromal PD (pPD) probability based on MDS research criteria. Abdominal skin punch biopsies were processed and stained using a conformation specific 5G4 α-syn antibody as well as axonal markers SMI-31 and S100. RESULTS: 5G4-positivity was identified in 23/28 PD patients, 20/24 iRBD subjects and 8/27 healthy controls. Compared to healthy controls, sensitivity and specificity reached 83.33 % and 70.37 % for iRBD; and 82.14 % and 70.37 % for PD, respectively. 5G4-positivity rate in our study was irrespective of the calculated pPD probability of iRBD subjects. CONCLUSIONS: This work establishes the diagnostic yield of conformation specific 5G4 α-syn antibody testing in skin biopsies of subjects with pPD, specifically iRBD. The diagnostic accuracy for this method seems to be similar for both manifest and prodromal PD and is not dependent on the pPD probability ratios.

Clinical, polysomnographic and genome-wide association analyses of narcolepsy with cataplexy: a European Narcolepsy Network study.

The aim of this study was to describe the clinical and PSG characteristics of narcolepsy with cataplexy and their genetic predisposition by using the retrospective patient database of the European Narcolepsy Network (EU-NN). We have analysed retrospective data of 1099 patients with narcolepsy diagnosed according to International Classification of Sleep Disorders-2. Demographic and clinical characteristics, polysomnography and multiple sleep latency test data, hypocretin-1 levels, and genome-wide genotypes were available. We found a significantly lower age at sleepiness onset (men versus women: 23.74 ± 12.43 versus 21.49 ± 11.83, P = 0.003) and longer diagnostic delay in women (men versus women: 13.82 ± 13.79 versus 15.62 ± 14.94, P = 0.044). The mean diagnostic delay was 14.63 ± 14.31 years, and longer delay was associated with higher body mass index. The best predictors of short diagnostic delay were young age at diagnosis, cataplexy as the first symptom and higher frequency of cataplexy attacks. The mean multiple sleep latency negatively correlated with Epworth Sleepiness Scale (ESS) and with the number of sleep-onset rapid eye movement periods (SOREMPs), but none of the polysomnographic variables was associated with subjective or objective measures of sleepiness. Variant rs2859998 in UBXN2B gene showed a strong association (P = 1.28E-07) with the age at onset of excessive daytime sleepiness, and rs12425451 near the transcription factor TEAD4 (P = 1.97E-07) with the age at onset of cataplexy. Altogether, our results indicate that the diagnostic delay remains extremely long, age and gender substantially affect symptoms, and that a genetic predisposition affects the age at onset of symptoms.

Psychotic Episode and Schizophrenia in Slovakian Narcolepsy Database.

Narcolepsy type 1 (NT1), a central disorder of hypersomnolence, is associated with mood, anxiety or hyperactivity mental disorders. Association with psychotic episode or schizophrenia is rare and could be the source of diagnostic and therapeutic difficulties. Their frequency in the national narcolepsy database has not been systematically studied. The aim of the presented study was to calculate the frequency of NT1 patients diagnosed with psychosis and/or schizophrenia, to identify clinical characteristics of these cases, and to look for narcoleptic and psychotic symptoms during re-evaluation years later. We identified three (4%) cases diagnosed with a psychotic episode in the course of NT1. They were diagnosed with NT1 by age ≤18 years. In the re-evaluation (mean follow-up 9.8 years), we identified one case with a dual diagnosis of NT1 and schizophrenia; two cases were diagnosed with a solitary psychotic episode in the course of NT1. NT1 patients diagnosed in the age ≤18 years are at higher risk of psychotic episode, and this may be related to higher vulnerability during the ongoing neurodevelopmental period. Comorbid schizophrenia with NT1 in the Slovakian Narcolepsy Database was within the prevalence expected in the general population. The solitary psychotic episode in the course of NT1 did not reduce the possibility of subsequent symptomatic treatment afterwards.

Idling for Decades: A European Study on Risk Factors Associated with the Delay Before a Narcolepsy Diagnosis.

Purpose: Narcolepsy type-1 (NT1) is a rare chronic neurological sleep disorder with excessive daytime sleepiness (EDS) as usual first and cataplexy as pathognomonic symptom. Shortening the NT1 diagnostic delay is the key to reduce disease burden and related low quality of life. Here we investigated the changes of diagnostic delay over the diagnostic years (1990-2018) and the factors associated with the delay in Europe. Patients and Methods: We analyzed 580 NT1 patients (male: 325, female: 255) from 12 European countries using the European Narcolepsy Network database. We combined machine learning and linear mixed-effect regression to identify factors associated with the delay. Results: The mean age at EDS onset and diagnosis of our patients was 20.9±11.8 (mean ± standard deviation) and 30.5±14.9 years old, respectively. Their mean and median diagnostic delay was 9.7±11.5 and 5.3 (interquartile range: 1.7-13.2 years) years, respectively. We did not find significant differences in the diagnostic delay over years in either the whole dataset or in individual countries, although the delay showed significant differences in various countries. The number of patients with short (≤2-year) and long (≥13-year) diagnostic delay equally increased over decades, suggesting that subgroups of NT1 patients with variable disease progression may co-exist. Younger age at cataplexy onset, longer interval between EDS and cataplexy onsets, lower cataplexy frequency, shorter duration of irresistible daytime sleep, lower daytime REM sleep propensity, and being female are associated with longer diagnostic delay. Conclusion: Our findings contrast the results of previous studies reporting shorter delay over time which is confounded by calendar year, because they characterized the changes in diagnostic delay over the symptom onset year. Our study indicates that new strategies such as increasing media attention/awareness and developing new biomarkers are needed to better detect EDS, cataplexy, and changes of nocturnal sleep in narcolepsy, in order to shorten the diagnostic interval.

Data-Driven Phenotyping of Central Disorders of Hypersomnolence With Unsupervised Clustering.

BACKGROUND AND OBJECTIVES: Recent studies fueled doubts as to whether all currently defined central disorders of hypersomnolence are stable entities, especially narcolepsy type 2 and idiopathic hypersomnia. New reliable biomarkers are needed, and the question arises of whether current diagnostic criteria of hypersomnolence disorders should be reassessed. The main aim of this data-driven observational study was to see whether data-driven algorithms would segregate narcolepsy type 1 and identify more reliable subgrouping of individuals without cataplexy with new clinical biomarkers. METHODS: We used agglomerative hierarchical clustering, an unsupervised machine learning algorithm, to identify distinct hypersomnolence clusters in the large-scale European Narcolepsy Network database. We included 97 variables, covering all aspects of central hypersomnolence disorders such as symptoms, demographics, objective and subjective sleep measures, and laboratory biomarkers. We specifically focused on subgrouping of patients without cataplexy. The number of clusters was chosen to be the minimal number for which patients without cataplexy were put in distinct groups. RESULTS: We included 1,078 unmedicated adolescents and adults. Seven clusters were identified, of which 4 clusters included predominantly individuals with cataplexy. The 2 most distinct clusters consisted of 158 and 157 patients, were dominated by those without cataplexy, and among other variables, significantly differed in presence of sleep drunkenness, subjective difficulty awakening, and weekend-week sleep length difference. Patients formally diagnosed as having narcolepsy type 2 and idiopathic hypersomnia were evenly mixed in these 2 clusters. DISCUSSION: Using a data-driven approach in the largest study on central disorders of hypersomnolence to date, our study identified distinct patient subgroups within the central disorders of hypersomnolence population. Our results contest inclusion of sleep-onset REM periods in diagnostic criteria for people without cataplexy and provide promising new variables for reliable diagnostic categories that better resemble different patient phenotypes. Cluster-guided classification will result in a more solid hypersomnolence classification system that is less vulnerable to instability of single features.

Comparison in detection of prodromal Parkinson's disease patients using original and updated MDS research criteria in two independent cohorts.

INTRODUCTION: MDS research criteria for prodromal Parkinson's disease (pPD) were published in 2015 and updated in 2019. We aimed to determine the difference in pPD patient detection rates in two cohorts recruited via gastrointestinal symptoms (PARCAS study) and the presence of a probable REM sleep behaviour disorder (PDBIOM study) using the original and updated criteria. METHODS: We evaluated all risk and prodromal markers, except genetic testing, plasma urate and physical inactivity, in both cohorts and DaT scan, diabetes mellitus type II and cognitive deficit in the PARCAS cohort. Thresholds of 50% probability for possible pPD and 80% for probable pPD were used. RESULTS: PPD status as identified by the original/updated criteria showed differences for probable pPD (n = 8/9; original/updated criteria) and possible pPD (n = 9/13) in the PARCAS cohort (total n = 158), as well as for probable pPD (n = 19/21) and possible pPD (n = 6/3) in the PDBIOM cohort (total n = 48). A high concordance rate was found between the two criteria sets (p < 0.001 for all groups). CONCLUSION: All probable pPD cases remained in the same category after evaluation with both criteria; three possible pPD cases based on the original criteria exceeded the threshold for probable pPD based on the updated criteria, and five possible new pPD cases were detected, with only one shift in the opposite direction. The updated MDS pPD research criteria tend to identify more patients as positive, yet their accuracy needs to be determined in prospective studies.

New 2013 incidence peak in childhood narcolepsy: more than vaccination?

Increased incidence rates of narcolepsy type-1 (NT1) have been reported worldwide after the 2009-2010 H1N1 influenza pandemic (pH1N1). While some European countries found an association between the NT1 incidence increase and the H1N1 vaccination Pandemrix, reports from Asian countries suggested the H1N1 virus itself to be linked to the increased NT1 incidence. Using robust data-driven modeling approaches, that is, locally estimated scatterplot smoothing methods, we analyzed the number of de novo NT1 cases (n = 508) in the last two decades using the European Narcolepsy Network database. We confirmed the peak of NT1 incidence in 2010, that is, 2.54-fold (95% confidence interval [CI]: [2.11, 3.19]) increase in NT1 onset following 2009-2010 pH1N1. This peak in 2010 was found in both childhood NT1 (2.75-fold increase, 95% CI: [1.95, 4.69]) and adulthood NT1 (2.43-fold increase, 95% CI: [2.05, 2.97]). In addition, we identified a new peak in 2013 that is age-specific for children/adolescents (i.e. 2.09-fold increase, 95% CI: [1.52, 3.32]). Most of these children/adolescents were HLA DQB1*06:02 positive and showed a subacute disease onset consistent with an immune-mediated type of narcolepsy. The new 2013 incidence peak is likely not related to Pandemrix as it was not used after 2010. Our results suggest that the increased NT1 incidence after 2009-2010 pH1N1 is not unique and our study provides an opportunity to develop new hypotheses, for example, considering other (influenza) viruses or epidemiological events to further investigate the pathophysiology of immune-mediated narcolepsy.