Background Virtual reality (VR)-based balance assessment tools are increasingly integrated into vestibular rehabilitation, yet preliminary reference data for semi-immersive optokinetic stimulation (OKS) remain limited. The Computer-Assisted Rehabilitation Environment (CAREN), a semi-immersive projection-based system, may reduce the risk of cybersickness compared to head-mounted displays, but its utility for characterizing stimulus-specific postural responses in healthy adults has not been established. Methods One hundred healthy participants underwent 12 trials, including pre- and post-test eyes-open and eyes-closed baselines and eight directional OKS conditions (yaw, pitch, roll, tunnel flow). Postural sway was quantified via center-of-pressure (COP) metrics: mean COP position, mean distance, root mean square (RMS) distance, mean velocity, and 95% confidence ellipse area. Results OKS increased postural sway relative to the eyes-open baseline, but the effect was stimulus- and metric-specific. Roll-plane OKS (clockwise and counter-clockwise) produced the largest disruption, with ellipse area more than three times the baseline value ( p < 0.001). Tunnel flow caused less postural disruption than roll. Sway increases were mainly anterior-posterior; ellipse area and medial-lateral RMS increased only during roll. Mean COP position showed a significant unidirectional lean only during roll (rightward with clockwise rotation, leftward with counter-clockwise rotation). Exploratory analyses found no association with age or sex. Conclusion Semi-immersive OKS elicits reproducible, stimulus-specific postural responses in healthy adults, with roll-plane stimuli producing maximal instability and tunnel flow engaging distinct adaptive mechanisms. These preliminary reference data provide benchmarks for characterizing healthy postural responses to semi-immersive OKS and support the design of future studies to validate stimulus-specific OKS paradigms in clinical populations.
BackgroundInconsistencies in outcome measures used in randomized controlled trials (RCTs) in Menière's Disease (MD) make it challenging to compare trial results. A Core Outcome Set (COS) standardizes outcome measures across studies, improving comparability and enhancing data synthesis for stronger evidence in clinical trials.ObjectiveTo develop a consensus-based COS for MD trials by identifying the most clinically relevant outcome domains and outcomes, using a Delphi procedure.MethodsTwo two-round Delphi surveys were conducted among international experts, including ENT specialists, neurologists, audiologists, and clinical researchers, to identify outcome domains and outcomes for inclusion in the COS. Participants assessed the importance of MD-related outcome domains in the first Delphi survey, and outcomes in the second Delphi survey using a 9-point Likert scale, with predefined consensus thresholds determining inclusion.ResultsA total of 112 experts from 35 countries participated in this study, each completing at least one Delphi round. In the first Delphi, consensus was reached on inclusion of six out of twelve predefined outcome domains: body function and structures, hearing, dizziness, tinnitus, aural fullness, and quality of life. In the second Delphi, consensus was reached on the inclusion of the following additional outcomes: dizziness severity, number of vertigo attacks, duration of vertigo attack, hearing loss, pure tone average, tinnitus severity, aural fullness severity, quality of life related to dizziness, quality of life related to hearing, quality of life related to social activity or work, drop attacks and vestibular function.ConclusionThis study represents a key phase of the COSMED-study through two structured, two-round Delphi procedures on outcome domains and outcomes to be considered in the COS for MD.
BackgroundSome patients with unilateral vestibular loss remain with persistent symptoms and posture and gait instability despite standard vestibular rehabilitation. This exploratory study examined the effects of neurofeedback training using a wearable mandibular vibrotactile device in patients with unilateral vestibular loss who had persistent symptoms and postural instability despite standard vestibular rehabilitation.MethodsTwelve patients who did not respond to standard vestibular rehabilitation underwent neurofeedback training using a wearable mandibular vibrotactile device providing real-time body tilt information in the roll plane via mandibular vibratory stimulation for 3 months. The Dizziness Handicap Inventory (DHI), posturography, and gait analysis were assessed before and after training without wearing the device.ResultsAfter neurofeedback training, the mean DHI score significantly decreased from 61.3 to 47.2 (p < 0.01). The total COP velocity with eyes closed significantly decreased from 3.79 to 3.08 cm/s (p < 0.05). The mediolateral COP velocity with eyes open and eyes closed significantly decreased from 1.25 to 0.96 cm/s and from 2.09 to 1.62 cm/s, respectively (p < 0.05). Gait stride length significantly increased from 1.11 to 1.21 m (p < 0.05), and gait speed significantly increased from 1.04 to 1.17 m/s (p < 0.05). The mediolateral center-of-mass path length during gait significantly decreased from 235.0 to 178.1 mm (p < 0.05).ConclusionsIn this exploratory study, neurofeedback training using a wearable mandibular vibrotactile device was associated with improved dizziness and postural instability in patients with unilateral vestibular loss who had persistent symptoms despite standard vestibular rehabilitation.
Objective The vestibulo-ocular reflex (VOR) is critical for stabilizing vision during head motion and for daily multitasking activities. The suppression head impulse paradigm (SHIMP) complements the head impulse paradigm (HIMP) and is considered more sensitive for residual vestibular function. This study examined the impact of cognitive and motor dual-tasking on SHIMP in healthy adults. Methods Twenty-two participants performed single-task HIMP and SHIMP alongside two cognitive dual-task SHIMP (serial subtraction, map navigation) and one motor dual-task SHIMP (counter clicking). Outcomes included VOR gain and anti-compensatory saccade parameters (number, latency, amplitude, duration, and peak velocity). Results VOR gain was lower in SHIMP than HIMP (0.827 +/- 0.140 vs 0.941 +/- 0.123; p < 0.001). Cognitive dual-task markedly affected anti-compensatory saccade, reducing saccade number (15-22%), prolonging latency (39-47%), decreasing amplitude (20%), shortening duration (similar to 5%), and reducing peak velocity (similar to 10%) (all p < 0.05). Motor dual-task modestly increased gain (0.868 +/- 0.131 vs 0.827 +/- 0.140; p = 0.025) but only increased anti-compensatory saccade latency by 17% (p < 0.05). Conclusions Dual-tasking exerted distinct effects on SHIMP outcomes. VOR gain remained largely preserved, whereas anti-compensatory saccades were substantially impaired. These findings highlight the contribution of central and attentional mechanisms to anti-compensatory saccade generation and suggest that these parameters may provide complementary information to VOR gain during SHIMP testing.
Background Virtual reality can simulate the testing of cognitive, sensory, and motor skills using simulated environments. Eye stabilization is necessary to maintain visual acuity during rapid head movements; this is achieved through mechanisms such as the vestibulo-ocular reflex. Objective This study aimed to investigate the short-term effect of a passive, non-interactive virtual reality stimulus on dynamic visual acuity and postural sway in healthy young adults. Methods 24 healthy young adults (9 males, 15 females) aged 20-39, with an average age of 26.08 +/- 4.14 were included in the study. All participants underwent the Sensory Organization Test (SOT), Static Visual Acuity Test (SVAT), Perception Time Test (PTT), Dynamic Visual Acuity Test (DVAT), Gaze Stabilization Test (GST), and Visual Analogue Scale (VAS) to assess symptoms that may arise from virtual reality. These tests were repeated for all participants after the virtual reality experience, and completed on the same day. Results Statistically significant differences were obtained in the balance score of the SOT (COMP, mean decrease 2.29 points, 95% CI 0.49-4.10, p = 0.015, Cohen's d = 0.54) and the left-side GST (mean increase 24.7 ms, 95% CI -45.82 to -3.64, p = 0.024, Cohen's d = -0.52) in the pre/post virtual reality experience comparison. Virtual reality had no statistically significant effect on SOT conditions 1-6 individually (all p > 0.05), although CON6 and PTT were borderline (CON6: p = 0.095, r = 0.34; PTT: p = 0.053, r = 0.40). No statistically significant differences were found between pre- and post-treatment in PTT and DVAT (both p > 0.05). Conclusion It has been demonstrated that a passive, non-interactive virtual reality stimulus may affect balance and gaze stabilization by increasing postural sway over a short, same-day time frame. Clinicians and researchers should be aware of these possible short-term effects when using similar VR-based paradigms for vestibular assessment and rehabilitation.
