Måns Magnusson

Motion sickness (MS) affects up to 2/3rds of the population traveling by car and most people will experience a form of MS in their life [1]. Currently, scopolamine and antihistamines are the main p...

Relevance of motion sickness Motion sickness, in all its forms, remains a universal human challenge. Whether it is seasickness that plagued the Vikings as they crossed the North Atlantic, carsickness affecting millions of daily commuters, or cybersickness emerging with the rapid growth of immersive digital technologies, motion-induced discomfort continues to shape how humans travel, work, and interact with their environments. It is estimated that up to one-third of people experience significant motion sickness under certain conditions, while nearly everyone is susceptible given sufficient stimulus intensity. Such prevalence makes motion sickness not a niche concern, but a global issue at the intersection of health, safety, and performance.In professional contexts, motion sickness has critical consequences. For example, naval personnel, pilots, astronauts, offshore workers, and even surgeons using robotic or virtual interfaces must perform with high precision in environments where motion-induced discomfort could impair concentration and operational ability. In everyday life, children experience high rates of carsickness, commuters struggle with nausea on buses and trains, and virtual reality users often abandon otherwise promising applications due to cybersickness. The costs are personal, economic, and societal. Motion sickness in global context The Icelandic setting for this congress provides a particularly resonant backdrop. As a nation built upon seafaring traditions, Icelanders have long faced the realities of motion sickness. Fishermen and sailors remain at risk during voyages that underpin the country's economy and cultural heritage. This lived experience emphasizes the urgency of advancing scientific solutions that not only reduce discomfort but also safeguard performance and safety.Globally, the problem has broadened. Beyond seasickness and carsickness, the rise of autonomous vehicles, commercial spaceflight, and extended reality technologies (XR) introduces entirely new domains where motion sickness can emerge. For autonomous vehicles, passenger comfort and trust are essential for adoption. In space exploration, motion sickness continues to threaten mission performance during critical phases of travel. In the virtual domain, cybersickness challenges the adoption of VR/AR in healthcare, training, education, and entertainment. Thus, Iceland hosts this congress not just as a symbolic center of maritime history but as an international hub where researchers, clinicians, and innovators unite to address one of humanity's oldest yet most pressing physiological challenges. Scientific frontiers in motion sickness research Over decades, research into motion sickness has evolved from descriptive accounts to highly sophisticated, interdisciplinary investigations. Several critical frontiers now define the field: i) quantitative evaluation - traditional reliance on subjective reporting is now complemented by advanced biosignal monitoring, neuroimaging, and machine learning approaches. These enable real-time assessment of motion sickness onset, progression, and recovery; il) pathophysiological understanding - competing theories of sensory conflict, postural instability, and vestibular-autonomic interaction continue to guide inquiry. Advances in neuroscience, including electroencephalography (EEG) and connectivity analyses, promise a more precise understanding of underlying processes; iii) technological countermeasures - from pharmacological interventions to novel behavioral, sensory, and cognitive strategies, researchers are exploring ways to mitigate symptoms without compromising alertness or function; iv) applied settingsinvestigations now span ships, aircraft, cars, trains, and virtual environments, reflecting the wide-reaching impact of motion sickness. Studies in autonomous vehicles, for example, explore prediction and mitigation strategies crucial for future mobility systems; v) individual differences - research increasingly accounts for age, sex, genetic predispositions, and psychological traits, moving toward personalized predictions of susceptibility and intervention strategies.By addressing these frontiers, the Congress aims to bridge fundamental science with practical application, ensuring that theoretical insights translate into real-world benefits. Congress theme and objectives The theme of this congress, "Quantitative evaluation of motion sickness," highlights the growing importance of objective, reproducible measures in advancing the field. Quantification allows researchers to compare findings across studies, develop predictive models, and evaluate the effectiveness of interventions. Without robust evaluation methods, progress risks being fragmented and anecdotal. The objectives of the congress are threefold: i) to foster innovation by bringing together experts from neuroscience, physiology, psychology, engineering, and clinical practice; ii) to inspire collaboration across national and into application by linking laboratory findings to challenges in transportation, healthcare, and technology design. Through lectures, discussions, and interactive sessions, participants will gain exposure to cutting-edge techniques while sharing their own advances in research and practice. The role of interdisciplinary collaboration Motion sickness research exemplifies the necessity of interdisciplinary science. Understanding the condition requires expertise in vestibular physiology, neurocognitive processes, biomechanics, pharmacology, psychology, and ergonomics. At the same time, addressing the problem in real-world settings calls upon engineering, design, and industry collaboration.For example, the design of autonomous vehicle interiors cannot ignore insights from vestibular science. Similarly, VR hardware and software developers must engage with neuroscientists to reduce cybersickness and ensure user safety. The congress thus creates a rare platform for crosssector dialogue, uniting...

Purpose: Sudden sensorineural hearing loss (SSNHL) is defined as 30 decibels (dB) hearing loss in 3 consecutive frequencies occurring within 72 h. Pure-tone average of four frequencies (PTA4) is commonly used to evaluate hearing levels but may not accurately reflect the recovery. We aimed to identify prognostic factors for recovery and to evaluate how recovery should be assessed, by comparing PTA4 with an individual pure-tone average (iPTA), including solely the hearing thresholds for the affected frequencies. Methods: Demographic, clinical, and audiologic factors were analyzed using multivariable linear and logistic regression models. A Bland-Altman plot was used to compare recovery measurements based on iPTA and PTA4. Results: In this cohort, the mean age was 57 years (range 19–91 years). Dizziness was a prominent negative predictive factor (logistic regression: iPTA OR 0.09 95% CI 0.02–0.38, for full recovery; linear regression: iPTA 14.4 dB poorer recovery). Tinnitus correlated with, on average, 4.9 dB poorer recovery ( P =0.043). Each day of delayed assessment was linked to a 0.84 dB reduction in recovery ( P P =0.003). Conclusion: Dizziness, tinnitus, and increasing disease duration until assessment are negative prognostic factors. Compared to PTA4, iPTA better reflects actual hearing recovery, particularly in frequency range-specific hearing loss.

The European Society for Clinical Evaluation of Balance Disorders (ESCEBD), based in Nancy, France, has been meeting yearly since 2005 to discuss equilibrium-related themes that are not yet clearly defined or standardized. One of our latest discussions was with regard to outlining strategies of internal and external compensation that may be used to cope with balance disorders. A Committee was elected to discuss the mechanisms of compensation that may be involved in coping with balance system disorders. Compensation, referring to the immediate or short-term adaptive mechanisms that are used to counterbalance the effects of deficiencies that disrupt balance maintenance, can include alternative strategies, resources, or environmental supports to overcome deficits or challenges associated with a deficiency. The strategies can be internal (i.e. utilizing the individual’s own multi-sensory neural integration, motor, and cognitive resources) or external (i.e. modifying the environment, or using assistive or adaptive devices) to reduce fall hazard and enhance safety. This report focuses principally on internal compensation, generated by sensorimotor processes of the central nervous system (CNS) in response to impairment of either sensory information (e.g. vestibular pathologies), the musculoskeletal system (e.g. lower limb amputation and myopathies) or the CNS itself (e.g. upper motor neuron syndrome). The multifactorial process of compensation may explain the limitations encountered by the CNS in compensating for complex bodily impairments and may also limit our understanding of how the CNS adapts to balance disorders. Newly developed devices, such as wearable sensory substitution devices, are on the horizon as possible tools.

In 2007, the Bárány Society embarked on a project to establish definitions of vestibular syndromes and disorders based on best available evidence, referred to as the International Classification of Vestibular Disorders (ICVD). Since then, numerous publications providing consensus-driven diagnostic criteria for vestibular symptoms, syndromes, and disorders have been published. Here, we reflect on the rationale for developing the ICVD as well as its subsequent achievements, challenges, and outlook. In this summary of the work of the ICVD to date, the authors will focus on practical aspects to help improve the utility and applicability of these diagnostic criteria moving forward.

Background: The efficacy of corticosteroids for treating acute vestibular neuritis, or acute unilateral vestibulopathy (AUVP), remains controversial. Objective: This study aimed to evaluate whether corticosteroids improve vestibular function and reduce symptoms in both acute and chronic phases of AUVP. Methods: This randomized, placebo-controlled, double-blind trial included patients with AUVP (ages 18–80) from emergency departments at three sites in southern Sweden. Patients were randomly assigned to one of three groups: placebo, 3-day or 10-day corticosteroid treatment. The steroid groups received intravenous betamethasone followed by oral steroids, while the placebo group received intravenous saline followed by oral placebo. The primary outcome was canal paresis (%) after 12 months, measured via caloric testing. Secondary outcomes included vHIT gain, Diary Vertigo score, Dizziness Handicap Inventory, and Hospital Anxiety and Depression Scale. Analyses were conducted on an intention-to-treat basis. The trial was registered with the EU Clinical Trials Register (EudraCT Number: 2014-005484-32) and ClinicalTrials.gov (NCT00802529). Results: From December 2015 to March 2021, 350 patients were screened, and 69 were included: 23 in the 10-day corticosteroid group, 22 in the 3-day corticosteroid group, and 24 in the placebo group. All groups showed significant improvement in caloric function over time ( p = .002), with no significant differences between groups at any time point ( p = .629). Change in caloric asymmetry from baseline to 12 months did not differ between the treatment groups and the placebo group: mean difference −8.34 (95% CI –25.93 to 9.26; p = .347) in the 10-day steroid group and −6.61 (−24.67 to 11.45; p = .467) in the 3-day steroid group, compared with placebo. Secondary outcomes showed no significant differences between groups. Corticosteroid treatments were well tolerated with no safety concerns. Conclusions: Corticosteroid treatment does not significantly improve caloric recovery, vHIT gain recovery, or subjective well-being in patients with AUVP.

Parkinson’s disease (PD) can produce postural abnormalities of the standing body position such as kyphosis. We investigated the effects of PD, deep brain stimulation (DBS) in the subthalamic nucleus (STN), vision and adaptation on body position in a well-defined group of patients with PD in quiet standing and during balance perturbations. Ten patients with PD and 25 young and 17 old control participants were recruited. Body position was measured with 3D motion tracking of the ankle, knee, hip, shoulder and head. By taking the ankle as reference, we mapped the position of the joints during quiet standing and balance perturbations through repeated calf muscle vibration. We did this to explore the effect of PD, DBS in the STN, and vision on the motor learning process of adaptation in response to the repeated stimulus. We found that patients with PD adopt a different body position with DBS ON vs. DBS OFF, to young and old controls, and with eyes open vs. eyes closed. There was an altered body position in PD with greater flexion of the head, shoulder and knee (p≤0.042) and a posterior position of the hip with DBS OFF (p≤0.014). With DBS ON, body position was brought more in line with the position taken by control participants but there was still evidence of greater flexion at the head, shoulder and knee. The amplitude of movement during the vibration period decreased in controls at all measured sites with eyes open and closed (except at the head in old controls with eyes open) showing adaptation which contrasted the weaker adaptive responses in patients with PD. Our findings suggest that alterations of posture and greater forward leaning with repeated calf vibration, are independent from reduced movement amplitude changes. DBS in the STN can significantly improve body position in PD although the effects are not completely reversed. Patients with PD maintain adaptive capabilities by leaning further forward and reducing movement amplitude despite their kyphotic posture.

Gait disorders are a relevant factor for falls and possible to measure with wearable devices. If a wearable sensor can detect differences in gait parameters between fallers and non-fallers has not yet been studied. The aim of this study was to measure and compare gait parameters, vestibular function, and balance performance between fallers and non-fallers among a group of older persons. Participants were senior members (n = 101) of a Swedish non-profit gymnastic association. Gait parameters were obtained using an inertial measurement unit (IMU) that the participants wore on the leg while walking an obstacle course and on an even surface. Vestibular function was assessed by the Head-shake test, the Head impulse test, and the Dix–Hallpike maneuver. Balance was assessed by the Timed Up and Go, the Timed Up and Go manual, and the Timed Up and Go cognitive tests. Falls during the 12-month follow-up period were monitored using fall diaries. Forty-two persons (41%) had fallen during the 12-month follow-up. Fallers had more limited ability to vary their gait (gait flexibility) than non-fallers (p < 0.001). No other differences between fallers and non-fallers were found. The use of gait flexibility, captured by an IMU, seems better for identifying future fallers among healthy older persons than Timed Up and Go or Timed Up and Go combined with a cognitive or manual task.