Gernot Walter Ernst

• Eikemo, Marie; Løseth, Guro Engvig; Carlyle, Molly; Trøstheim, Martin Ostenfeldt; Ernst, Gernot Walter & Pazmandi, Claudia [Show all 14 contributors for this article] (2026). Effects of psychosocial stress on opioid self-administration in healthy participants: a randomized, placebo-controlled crossover trial. Nature Mental Health. doi: 10.1038/s44220-026-00700-x. Full text in Research Archive
• Bajwa, Imad Javaid; Nilsen, Andre Sevenius; Skukies, René Sebastian; Aamodt, Arnfinn; Ernst, Gernot Walter & Storm, Johan Frederik [Show all 7 contributors for this article] (2025). A repeated awakening study exploring the capacity of complexity measures to capture dreaming during propofol sedation | Scientific Reports. Scientific Reports. 15, p. 1–12. doi: 10.1038/s41598-025-12695-z. Full text in Research Archive Show summary

  Patients undergoing general anesthesia are often assumed to be unconscious. However, it is known that conscious experiences in the form of dreams occur even in unresponsive states induced by anesthetics. Here, we recorded resting state electroencephalography (EEG) as well as EEG combined with TMS perturbations in 20 healthy participants during propofol sedation. Participants were repeatedly awoken from deep sedation and asked immediately whether they had experiences just before waking up and what they experienced. Out of the 52 attempted awakenings in this study, 24 produced reports of having had an experience, while there were 5 reports of no experience. In the remaining 23 attempts, the subject was either unarousable or the report too incoherent to provide information about their experience prior to awakening. We then tested whether two different consciousness measures based on EEG complexity—the state transitions perturbational complexity index (PCIst) and single-channel Lempel-Ziv complexity (LZc)—differed between awakenings with and without experience. While our study confirms earlier findings that the EEG complexity measures significantly decrease from the awake state to the sedated state, we find no evidence that these measures differ between periods associated with reports of dreaming and non-dreaming, within the sedated state. A few interpretations and limitations are discussed.

• Bajwa, Imad Javaid; Nilsen, Andre Sevenius; Skukies, René Sebastian; Aamodt, Arnfinn; Ernst, Gernot Walter & Storm, Johan Frederik [Show all 7 contributors for this article] (2025). A repeated awakening study exploring the capacity of complexity measures to capture dreaming during propofol sedation. Scientific Reports. 15. doi: 10.1038/s41598-025-12695-z. Full text in Research Archive Show summary

  Patients undergoing general anesthesia are often assumed to be unconscious. However, it is known that conscious experiences in the form of dreams occur even in unresponsive states induced by anesthetics. Here, we recorded resting state electroencephalography (EEG) as well as EEG combined with TMS perturbations in 20 healthy participants during propofol sedation. Participants were repeatedly awoken from deep sedation and asked immediately whether they had experiences just before waking up and what they experienced. Out of the 52 attempted awakenings in this study, 24 produced reports of having had an experience, while there were 5 reports of no experience. In the remaining 23 attempts, the subject was either unarousable or the report too incoherent to provide information about their experience prior to awakening. We then tested whether two different consciousness measures based on EEG complexity—the state transitions perturbational complexity index (PCIst) and single-channel Lempel-Ziv complexity (LZc)—differed between awakenings with and without experience. While our study confirms earlier findings that the EEG complexity measures significantly decrease from the awake state to the sedated state, we find no evidence that these measures differ between periods associated with reports of dreaming and non-dreaming, within the sedated state. A few interpretations and limitations are discussed.

• Viermyr, Hans-Kittil; Halvorsen, Bente; Sagen, Ellen Lund; Michelsen, Annika Elisabet; Barratt-Due, Andreas & Kåsine, Trine [Show all 73 contributors for this article] (2024). High viral loads combined with inflammatory markers predict disease severity in hospitalized COVID-19 patients: Results from the NOR-Solidarity trial. Journal of Internal Medicine. ISSN 0954-6820. 296(3), p. 249–259. doi: 10.1111/joim.13820. Full text in Research Archive Show summary

  Objectives To investigate temporal changes in the association between SARS-CoV2 viral load (VL) and markers of inflammation during hospitalization, as well as the ability of these markers alone or in combination to predict severe outcomes. Methods Serial oropharyngeal and blood samples were obtained from hospitalized COVID-19 patients (n = 160). Levels of inflammatory markers and oropharyngeal VL were measured during hospitalization (admission, days 3–5, and days 7–10) and related to severe outcomes (respiratory failure/intensive care unit admission). Results Elevated admission levels of IL (interleukin)-6, IL-33, IL-8, monocyte chemoattractant protein-1 (MCP-1), interferon-γ-induced protein 10 (IP-10), IL-1β, and IL-1Ra were associated with severe outcomes during hospitalization. Although no inflammatory markers correlated with VL at baseline, there was a significant correlation between VL and levels of IP-10 and MCP-1 at days 3–5, accompanied by IL-8 and IL-6 at days 7–10. Finally, there was a seemingly additive effect of IP-10, MCP-1, and IL-6 in predicting severe outcomes when combined with high VL at baseline. Conclusions An increasing number of inflammatory markers were associated with VL during the first 10 days of hospitalization, and several of these markers were associated with severe outcomes, in particular when combined with elevated VL. Future studies should assess the potential for combining antiviral and immunomodulatory treatment, preferably guided by viral and inflammatory biomarkers, for the selection of high-risk patients.

• Heinz, Andreas; Gutwinski, Stefan; Krausz, Michael; Ernst, Gernot Walter; Vogel, Marc & Scherbaum, Norbert (2024). Challenges in the treatment of opioid dependence. Nervenarzt. ISSN 0028-2804. 95(9), p. 811–817. doi: 10.1007/s00115-024-01691-9. Full text in Research Archive
• Carlyle, Molly; Kvande, Malin; Meier, Isabell M.; Trøstheim, Martin Ostenfeldt; Buen, Kaja & Jensen, Eira Nordeng [Show all 9 contributors for this article] (2023). Does childhood adversity alter opioid drug reward? A conceptual replication in outpatients before surgery. Addiction Research and Theory. ISSN 1606-6359. doi: 10.1080/16066359.2023.2211348. Full text in Research Archive
• Eikemo, Marie; Meier, Isabell M.; Løseth, Guro Engvig; Trøstheim, Martin Ostenfeldt; Ørstavik, Nikoline & Jensen, Eira Nordeng [Show all 10 contributors for this article] (2023). Opioid analgesic effects on subjective well-being in the operating theatre*. Anaesthesia. ISSN 0003-2409. 78(9), p. 1102–1111. doi: 10.1111/anae.16069. Full text in Research Archive
• Meier, Isabell M.; Eikemo, Marie; Trøstheim, Martin Ostenfeldt; Buen, Kaja; Jensen, Eira Nordeng & Karlsen, Siri Gurandsrud [Show all 10 contributors for this article] (2023). Factors associated with use of opioid rescue medication after surgery. Regional anesthesia and pain medicine. ISSN 1098-7339. doi: 10.1136/rapm-2023-104412. Full text in Research Archive
• Snitz, Kobi; Honigstein, Danielle; Weissgross, Reut; Ravia, Aharon; Mishor, Eva & Perl, Ofer [Show all 29 contributors for this article] (2022). An olfactory self-test effectively screens for COVID-19. Communications Medicine. 2(1). doi: 10.1038/s43856-022-00095-7. Full text in Research Archive
• Pan, Hongchao; Peto, Richard; Karim, Quarraisha Abdool; Alejandria, Marissa M.; Henao-Restrepo, Ana-Maria & Hernández-García, César [Show all 51 contributors for this article] (2022). Remdesivir and three other drugs for hospitalised patients with COVID-19: final results of the WHO Solidarity randomised trial and updated meta-analyses. The Lancet. ISSN 0140-6736. 399(10339), p. 1941–1953. doi: 10.1016/S0140-6736(22)00519-0. Full text in Research Archive Show summary

  Background The Solidarity trial among COVID-19 inpatients has previously reported interim mortality analyses for four repurposed antiviral drugs. Lopinavir, hydroxychloroquine, and interferon (IFN)-β1a were discontinued for futility but randomisation to remdesivir continued. Here, we report the final results of Solidarity and meta-analyses of mortality in all relevant trials to date. Methods Solidarity enrolled consenting adults (aged ≥18 years) recently hospitalised with, in the view of their doctor, definite COVID-19 and no contraindication to any of the study drugs, regardless of any other patient characteristics. Participants were randomly allocated, in equal proportions between the locally available options, to receive whichever of the four study drugs (lopinavir, hydroxychloroquine, IFN-β1a, or remdesivir) were locally available at that time or no study drug (controls). All patients also received the local standard of care. No placebos were given. The protocol-specified primary endpoint was in-hospital mortality, subdivided by disease severity. Secondary endpoints were progression to ventilation if not already ventilated, and time-to-discharge from hospital. Final log-rank and Kaplan-Meier analyses are presented for remdesivir, and are appended for all four study drugs. Meta-analyses give weighted averages of the mortality findings in this and all other randomised trials of these drugs among hospital inpatients. Solidarity is registered with ISRCTN, ISRCTN83971151, and ClinicalTrials.gov, NCT04315948. Findings Between March 22, 2020, and Jan 29, 2021, 14 304 potentially eligible patients were recruited from 454 hospitals in 35 countries in all six WHO regions. After the exclusion of 83 (0·6%) patients with a refuted COVID-19 diagnosis or encrypted consent not entered into the database, Solidarity enrolled 14 221 patients, including 8275 randomly allocated (1:1) either to remdesivir (ten daily infusions, unless discharged earlier) or to its control (allocated no study drug although remdesivir was locally available). Compliance was high in both groups. Overall, 602 (14·5%) of 4146 patients assigned to remdesivir died versus 643 (15·6%) of 4129 assigned to control (mortality rate ratio [RR] 0·91 [95% CI 0·82–1·02], p=0·12). Of those already ventilated, 151 (42·1%) of 359 assigned to remdesivir died versus 134 (38·6%) of 347 assigned to control (RR 1·13 [0·89–1·42], p=0·32). Of those not ventilated but on oxygen, 14·6% assigned to remdesivir died versus 16·3% assigned to control (RR 0·87 [0·76–0·99], p=0·03). Of 1730 not on oxygen initially, 2·9% assigned to remdesivir died versus 3·8% assigned to control (RR 0·76 [0·46–1·28], p=0·30). Combining all those not ventilated initially, 11·9% assigned to remdesivir died versus 13·5% assigned to control (RR 0·86 [0·76–0·98], p=0·02) and 14·1% versus 15·7% progressed to ventilation (RR 0·88 [0·77–1·00], p=0·04). The non-prespecified composite outcome of death or progression to ventilation occurred in 19·6% assigned to remdesivir versus 22·5% assigned to control (RR 0·84 [0·75–0·93], p=0·001). Allocation to daily remdesivir infusions (vs open-label control) delayed discharge by about 1 day during the 10-day treatment period. A meta-analysis of mortality in all randomised trials of remdesivir versus no remdesivir yielded similar findings. Interpretation Remdesivir has no significant effect on patients with COVID-19 who are already being ventilated. Among other hospitalised patients, it has a small effect against death or progression to ventilation (or both).

• Blesius, Valeria; Schölzel, Christopher; Ernst, Gernot Walter & Dominik, Andreas (2022). Comparability of Heart Rate Turbulence Methodology: 15 Intervals Suffice to Calculate Turbulence Slope – A Methodological Analysis Using PhysioNet Data of 1074 Patients. Frontiers in Cardiovascular Medicine. 9. doi: 10.3389/fcvm.2022.793535. Full text in Research Archive
• Schölzel, Christopher; Blesius, Valeria; Ernst, Gernot & Dominik, Andreas (2021). Characteristics of mathematical modeling languages that facilitate model reuse in systems biology: a software engineering perspective. npj Systems Biology and Applications. 7:27, p. 1–20. doi: 10.1038/s41540-021-00182-w. Full text in Research Archive
• Schölzel, Christopher; Blesius, Valeria; Ernst, Gernot Walter; Goesmann, Alexander & Dominik, Andreas (2021). Countering reproducibility issues in mathematical models with software engineering techniques: A case study using a one-dimensional mathematical model of the atrioventricular node. PLOS ONE. 16(7), p. 1–36. doi: 10.1371/journal.pone.0254749. Full text in Research Archive
• Kåsine, Trine; Riise, Anne Margarita Dyrhol; Barratt-Due, Andreas; Kildal, Anders Benjamin; Olsen, Inge Christoffer & Nezvalova-Henriksen, Katerina [Show all 39 contributors for this article] (2021). Neutrophil count predicts outcome in hospitalized COVID-19 patients. Results from the NOR-Solidarity trial. Journal of Internal Medicine. ISSN 0954-6820. 291(2), p. 241–243. doi: 10.1111/joim.13377. Full text in Research Archive Show summary

  Despite numerous studies on SARS-CoV-2-induced inflammation, we still lack markers for rapid disease progression with admission to intensive care unit (ICU) or respiratory failure(RF). Few studies have evaluated the prognostic value of routine diagnostic repertoire available at most hospitals. The NOR-Solidarity trial is an independent add-on study to the WHO Solidarity trial, evaluating hydroxychloroquine (HCQ)and remdesivir compared to standard of care in hospitalized COVID-19 patients [1]. We explored whether standard biomarkers in peripheral blood could give information on ICU admission and RFin hospitalized COVID-19 patients.

• Laeng, Bruno; Garvija, Lara; Løseth, Guro Engvig; Eikemo, Marie; Ernst, Gernot & Leknes, Siri (2021). ‘Defrosting’ music chills with naltrexone: The role of endogenous opioids for the intensity of musical pleasure. Consciousness and Cognition. ISSN 1053-8100. 90. doi: 10.1016/j.concog.2021.103105. Full text in Research Archive
• Ernst, Gernot Walter; Watne, Leiv Otto; Frihagen, Frede; Wyller, Torgeir Bruun; Dominik, Andreas & Rostrup, Morten (2021). Low Heart Rate Variability Predicts Stroke and Other Complications in the First Six Postoperative Months After a Hip Fracture Operation. Frontiers in Cardiovascular Medicine. 8, p. 1–8. doi: 10.3389/fcvm.2021.640970. Full text in Research Archive
• Barratt-Due, Andreas; Olsen, Inge Christoffer; Nezvalova-Henriksen, Katerina; Kåsine, Trine; Lund-Johansen, Fridtjof & Hoel, Hedda Benedicte [Show all 43 contributors for this article] (2021). Evaluation of the Effects of Remdesivir and Hydroxychloroquine on Viral Clearance in COVID-19 : A Randomized Trial. Annals of Internal Medicine. ISSN 0003-4819. 174(9), p. 1261–1269. doi: 10.7326/M21-0653. Full text in Research Archive Show summary

  Background: New treatment modalities are urgently needed for patients with COVID-19. The World Health Organization (WHO) Solidarity trial showed no effect of remdesivir or hydroxychloroquine (HCQ) on mortality, but the antiviral effects of these drugs are not known. Objective: To evaluate the effects of remdesivir and HCQ on all-cause, in-hospital mortality; the degree of respiratory failure and inflammation; and viral clearance in the oropharynx. Design: NOR-Solidarity is an independent, add-on, randomized controlled trial to the WHO Solidarity trial that included biobanking and 3 months of clinical follow-up (ClinicalTrials.gov: NCT04321616). Setting: 23 hospitals in Norway. Patients: Eligible patients were adults hospitalized with confirmed SARS-CoV-2 infection. Intervention: Between 28 March and 4 October 2020, a total of 185 patients were randomly assigned and 181 were included in the full analysis set. Patients received remdesivir (n = 42), HCQ (n = 52), or standard of care (SoC) (n = 87). Measurements: In addition to the primary end point of WHO Solidarity, study-specific outcomes were viral clearance in oropharyngeal specimens, the degree of respiratory failure, and inflammatory variables. Results: No significant differences were seen between treatment groups in mortality during hospitalization. There was a marked decrease in SARS-CoV-2 load in the oropharynx during the first week overall, with similar decreases and 10-day viral loads among the remdesivir, HCQ, and SoC groups. Remdesivir and HCQ did not affect the degree of respiratory failure or inflammatory variables in plasma or serum. The lack of antiviral effect was not associated with symptom duration, level of viral load, degree of inflammation, or presence of antibodies against SARS-CoV-2 at hospital admittance. Limitation: The trial had no placebo group. Conclusion: Neither remdesivir nor HCQ affected viral clearance in hospitalized patients with COVID-19.

• Ernst, Gernot; Watne, Leiv; Rostrup, Morten & Neerland, Bjørn Erik (2020). Delirium in patients with hip fracture is associated with increased heart rate variability. Aging Clinical and Experimental Research. ISSN 1594-0667. 32, p. 2311–2318. doi: 10.1007/s40520-019-01447-5. Full text in Research Archive
• Blesius, Valeria; Schölzel, Christopher; Ernst, Gernot & Dominik, Andreas (2020). HRT assessment reviewed: A systematic review of heart rate turbulence methodology. Physiological Measurement. ISSN 0967-3334. 41(8). doi: 10.1088/1361-6579/ab98b3. Full text in Research Archive
• Iravani, Behzad; Arshamian, Artin; Ravia, Aharon; Mishor, Eva; Snitz, Kobi & Shushan, Sagit [Show all 25 contributors for this article] (2020). Relationship between odor intensity estimates and COVID-19 prevalence prediction in a Swedish population. Chemical Senses. ISSN 0379-864X. 45(6), p. 449–456. doi: 10.1093/chemse/bjaa034. Full text in Research Archive
• Schölzel, Christopher; Blesius, Valeria; Ernst, Gernot & Dominik, Andreas (2020). An Understandable, Extensible, and Reusable Implementation of the Hodgkin-Huxley Equations Using Modelica. Frontiers in Physiology. 11. doi: 10.3389/fphys.2020.583203. Full text in Research Archive Show summary

  The Hodgkin-Huxley model of the squid giant axon has been used for decades as the basis of many action potential models. These models are usually communicated using just a list of equations or a circuit diagram, which makes them unnecessarily complicated both for novices and for experts. We present a modular version of the Hodgkin-Huxley model that is more understandable than the usual monolithic implementations and that can be easily reused and extended. Our model is written in Modelica using software engineering concepts, such as object orientation and inheritance. It retains the electrical analogy, but names and explains individual components in biological terms. We use cognitive load theory to measure understandability as the amount of items that have to be kept in working memory simultaneously. The model is broken down into small self-contained components in human-readable code with extensive documentation. Additionally, it features a hybrid diagram that uses biological symbols in an electrical circuit and that is directly tied to the model code. The new model design avoids many redundancies and reduces the cognitive load associated with understanding the model by a factor of 6. Extensions can be easily applied due to an unifying interface and inheritance from shared base classes. The model can be used in an educational context as a more approachable introduction to mathematical modeling in electrophysiology. Additionally the modeling approach and the base components can be used to make complex Hodgkin-Huxley-type models more understandable and reusable.

• Garland, Eric; Trøstheim, Martin; Eikemo, Marie; Ernst, Gernot & Leknes, Siri (2019). Anhedonia in chronic pain and prescription opioid misuse. Psychological Medicine. ISSN 0033-2917. p. 1–12. doi: 10.1017/S0033291719002010. Full text in Research Archive
• Ernst, Gernot Walter; Watne, Leiv Otto; Frihagen, Frede Jon; Wyller, Torgeir Bruun; Dominik, Andreas & Rostrup, Morten (2017). Decreases in heart rate variability are associated with postoperative complications in hip fracture patients. PLOS ONE. 12:e0180423(7), p. 1–14. doi: 10.1371/journal.pone.0180423. Full text in Research Archive
• Ernst, Gernot (2017). Hidden signals - the history and Methods of heart rate variability. Frontiers in Public Health. 5. doi: 10.3389/fpubh.2017.00265. Full text in Research Archive
• Ernst, Gernot (2017). Heart-Rate Variability - More than Heart Beats? Frontiers in Public Health. 5. doi: 10.3389/fpubh.2017.00240. Full text in Research Archive
• Menzel, Michael; Schölzel, Christopher; Ernst, Gernot Walter & Dominik, Andreas (2016). Silicon Hearth: An easy to use interactive real-time baroreflex stimulator. Computing in cardiology. ISSN 2325-8861. 42, p. 973–976. doi: 10.1109/CIC.2015.7411075. Full text in Research Archive

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• Ernst, Gernot Walter (2014). Heart Rate Variability. Springer. ISBN 9781447143086. 336 p. Full text in Research Archive

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• Blesius, Valeria; Schölzel, Christopher; Ernst, Gernot & Dominik, Andreas (2021). Erratum: HRT assessment reviewed: A systematic review of heart rate turbulence methodology. Physiological Measurement. ISSN 0967-3334. 42(1). doi: 10.1088/1361-6579/abcf16. Full text in Research Archive
• Ernst, Gernot Walter & Rostrup, Morten (2010). HEART RATE VARIABILITY IN PALLIATIVE PATIENTS - A PILOT STUDY. Journal of Hypertension. ISSN 0263-6352. 28, p. E467–E467. Full text in Research Archive

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