EAN 2026 | iSPHYNCS study: new biomarkers in central disorders of hypersomnolence

The patients in the center of the International Swiss Primary Hypersomnolence and Narcolepsy Cohort Study, or iSPHYNCS, are patients who present to the sleep clinic with excessive daytime sleepiness, sleep attacks or an excessive need of sleep, so long hours of sleep over 24 hours, for unknown reasons. And if those patients additionally show cataplexy, which are short and transient moments of muscle weakness, or other symptoms like hypnagogic hallucinations, then the sleep clinician might have the suspicion of narcolepsy type 1 and might even be correct about this. But if those additional symptoms are not there it is actually very difficult to diagnose and in the end also to treat those patients. So in 2020 we started the Swiss primary hypersomnolence and narcolepsy cohort study which later in 2023 became international and here in Switzerland actually within Bern and there are currently eight participating centers all over Switzerland and four international centers. And this study is a well multicentric prospective longitudinal observational cohort study including exactly this group of patients, patients with hypersomnolence or excessive daytime sleepiness with the suspicion of a central disorder of hypersomnolence and then we follow them up over three years. So far we have included 412 individuals, this was my last number, including 57 healthy controls, and we collect multimodal data types. And there is first hypothesis-driven approaches to analyze those data. And in the end, we also would like to employ more unsupervised approaches from the machine learning area to analyze those data and to put them all together, which might help us to find new phenotypes and hidden clusters maybe in this very complicated group of disorders. So several publications have so far resulted from this study. So most recently we published the detection of a fragment of hypocretin-1 and a method to measure hypocretin-1 and its fragment in the cerebrospinal fluid with mass spectrometry. We have also analyzed questionnaires and metadata by clustering approaches and found out that there might be different groups in this narcolepsy borderland, one of which is mainly defined by more affective symptoms or like more depression and also anxiety. We have also shown that there is a high prevalence of psychiatric comorbidities in our cohort, both in patients with narcolepsy type 1, but even more, almost 50% in patients with other central disorders of hypersomnolence, and that those psychiatric comorbidities actually significantly reduce quality of life and also lead to other hypersomnolence-related symptoms being a larger burden to the patient. So I think the conclusion here can be that psychiatric comorbidities should be treated in this patient cohort or in this patient population since they are quite relevant. We have also shown that long-term analysis with smartwatches, in our case it is a Fitbit smartwatch which is distributed to the patients over one year, that this is feasible in such a patient cohort. We had quite good adherence rates and we also showed that there are potential group differences in narcolepsy type 1 and controls and just analyzing Fitbit data or smartwatch data. And we also showed that calorie consumption is a good proxy for non-parametric circadian rhythm analysis if we compare smartwatch data to actigraphy data. And in the end we also could show that the Swiss narcolepsy scale to detect narcolepsy type 1 also worked in our population. So the iSPHYNCS study is really a team effort of a very large and international team of dedicated physicians and researchers. There are students, PhD students, doctoral students working on this study, study nurses, we have a study coordinator, a data manager and all those people are doing really good work to make this very large and very complicated study going with the hope to find new biomarkers for central disorders of hypersomnolence.

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