Search Results (59)

Peripheral vestibulopathy (PV) is a common disorder that causes dizziness and balance impairment, substantially affecting patients’ quality of life. When symptoms persist, they frequently lead to anxiety, depression, and an increased risk of social isolation. Although central vestibular compensation (CVC) often promotes functional recovery, current pharmacological options remain limited and are primarily aimed at symptom control. Consequently, they should be considered adjuncts rather than alternatives to rehabilitation-based strategies. Vestibular rehabilitation (VR) remains the cornerstone of treatment for promoting functional recovery in patients with PV. Based on the complementary mechanisms of adaptation, substitution, and habituation, VR enhances the central nervous system’s ability to compensate for vestibular deficits by optimizing the integration of visual, proprioceptive, and residual vestibular inputs. Robust evidence from both clinical and preclinical studies has demonstrated its efficacy in improving postural stability, dynamic balance, gaze stabilization, and overall functional performance. Experimental studies using animal models have further highlighted the critical role of active sensorimotor training in ecologically relevant environments for enhancing vestibular compensation. Pharmacological interventions may further facilitate these adaptive processes by modulating the neurobiological mechanisms underlying vestibular compensation, thereby improving responsiveness to rehabilitation. Likewise, emerging neuromodulation approaches, including galvanic vestibular stimulation, have shown promising potential to enhance neural plasticity and augment the effects of rehabilitation. Consequently, combining VR with targeted pharmacological therapies and/or vestibular stimulation techniques may provide synergistic benefits and maximize functional recovery. In conclusion, vestibular rehabilitation should remain the foundation of PV management and be integrated with pharmacological and neuromodulatory approaches within a multidisciplinary therapeutic framework. Further research is needed to optimize rehabilitation protocols, identify the biological determinants of successful vestibular compensation, and develop personalized therapeutic strategies aimed at maximizing functional recovery and improving patients’ quality of life. Full article

Background: Digital workflows in implant prosthodontics continue to evolve, yet standardized protocols integrating clinician-driven abutment customization and peri-implant soft-tissue conditioning remain limited. This pilot study aimed to present and evaluate a progressive gingival digital workflow for cement-retained implant-supported restorations based on chairside adjustment of prefabricated abutments according to gingival maturation. Methods: A retrospective comparative study included 39 patients rehabilitated with 161 implants and followed for 24–48 months. The experimental group comprised 87 bone-level implants restored using a progressive digital workflow involving staged healing, chairside abutment customization, provisional tissue conditioning, and digital fabrication of definitive restorations. Outcomes were compared with 74 tissue-level implants restored using a conventional protocol with healing abutments and prefabricated prosthetic abutments. Clinical and radiographic outcomes included plaque index, bleeding on probing (BOP), peri-implant sulcus depth, marginal bone resorption, complications, and patient satisfaction. Results: Both groups demonstrated favorable clinical outcomes, with no significant differences in plaque index, gingival condition, BOP (28.74% vs. 21.62%), sulcus dimensions, or marginal bone resorption (11.49% vs. 12.16%) (p > 0.05). Logistic regression identified plaque accumulation, vestibular sulcus depth, and implant duration as predictors of BOP, whereas implant type was not associated with BOP or bone resorption. Patient satisfaction, assessed using a visual analog scale, was uniformly high. Most patients reported maximum scores across all domains, with only minor esthetic concerns reported by a few participants. No major prosthetic complications or screw loosening occurred during follow-up. Conclusions: The proposed workflow demonstrated favorable clinical performance and appears to be a feasible restorative approach. However, because implant design and restorative workflow differed simultaneously, findings should be interpreted cautiously. Larger prospective studies are needed to confirm these results. Full article

Background/Objectives. Spinal misalignment in childhood and adolescence may be associated with altered sensory integration and body representation. The subjective visual vertical reflects visual, vestibular, and somatosensory integration, but its relationship with pediatric spinal misalignment remains uncertain. This study investigated the subjective visual vertical using two complementary paradigms. Methods. This exploratory, single-center, cross-sectional study included participants aged 7–17 years with clinically identified spinal misalignment. Participants underwent standardized physiatric assessment and subjective visual vertical testing using a luminous-line test and the Bucket Test. Spearman’s rank correlations examined associations with clinical and radiographic variables, with false-discovery-rate control using the Benjamini–Hochberg procedure. Radiographic analyses were restricted to participants with available imaging. Results. Fifty-seven participants were included (mean age 12.8 years, SD 2.25), and all completed both tests. Mean subjective visual vertical was 0.053° (SD 0.953) with the luminous-line test and −0.561° (SD 1.165) with the Bucket Test. Radiographs were available for 21 participants. No association remained significant after false-discovery-rate correction. Two luminous-line associations were nominally significant before correction: primary lumbar curve presence (ρ = −0.278, p = 0.036) and secondary thoracolumbar curve presence (ρ = −0.324, p = 0.015); both had q = 0.721. The tests were moderately correlated (ρ = 0.493, p < 0.001). Radiographic sensitivity and subgroup analyses showed no significant findings. Conclusions. Subjective visual vertical was not robustly associated with spinal misalignment characteristics in this modest, clinically heterogeneous cohort. Larger controlled studies with standardized imaging and adequately powered severity groups are required. Full article

Background/Objectives: Postural control depends on the integration and reweighting of visual, somatosensory, vestibular, and contextual sensory information. Stable auditory cues may support balance, whereas complex musical stimulation may impose additional sensory-cognitive demand during multisensory conflict. This study examined the acute effects of relative device-output music intensity on virtual-reality-based postural control in trained athletes and explored whether responses differed by sport background. Methods: Forty-eight athletes from tennis, combat sports, swimming, football, and volleyball completed the Clinical Test of Sensory Interaction in Balance delivered through virtual reality (CTSIB-VR) and Limits of Stability (LOS) assessments under four auditory conditions: routine/no sound and low (+10 dB), moderate (+20 dB), and high (+30 dB) relative device-output increments. Linear mixed-effects models included sport, auditory condition, and their interaction as fixed effects and participant-specific random intercepts and random linear condition slopes. Model-based estimated marginal means, Bonferroni-adjusted contrasts, 1.5×IQR sensitivity analyses, and robust generalized estimating equations were calculated. Results: Auditory condition affected all five CTSIB-VR outcomes (Wald χ²(3) = 16.773–94.404, all p < 0.001). The routine condition exceeded the high-intensity condition for composite score (adjusted mean difference = 6.05, 95% CI 3.99–8.10; Bonferroni-adjusted p < 0.001) and somatosensory score (8.62, 95% CI 6.78–10.46; adjusted p < 0.001). Sport × condition interactions were significant for all CTSIB-VR outcomes (χ²(12) = 54.869–98.953, all p < 0.001), but sport-stratified findings were exploratory. For LOS, auditory-condition effects were detected for endpoint excursion (p = 0.004), maximum excursion (p < 0.001), and directional control (p = 0.002), whereas reaction time (p = 0.648) and movement velocity (p = 0.056) did not show clear main effects. Sensitivity analyses supported the endpoint-excursion, maximum-excursion, and directional-control findings; movement-velocity inference was method-sensitive. Conclusions: Relative device-output music intensity was associated with consistent changes in CTSIB-VR sensory-organization measures and outcome-specific changes in LOS performance. Sport-related patterns require confirmation in adequately powered, balanced samples. Full article

(1) Background: The effects of posterior parietal cortex (PPC)-targeted transcranial direct current stimulation (tDCS) on postural stability and cortical activity remain unclear. Therefore, this study aimed to investigate and compare changes in cortical activity and postural stability before and following tDCS conditions. (2) Methods: Eight right-handed adults completed a baseline assessment followed by three stimulation sessions: left-anodal/right-cathodal (L-A/R-C), left-cathodal/right-anodal (L-C/R-A), and sham on the PPC. The sessions were administered in a randomized Latin square design with a minimum 4-day washout period between each. At baseline and following each tDCS session, cortical activity was measured using functional near-infrared spectroscopy, and postural stability during a tandem stance was assessed utilizing the Balance Error Scoring System (BESS) and a force platform. (3) Results: Compared with the baseline measurements, significant deactivation in the right middle temporal gyrus (MTG) was observed following L-C/R-A stimulation. Furthermore, postural stability measures revealed significantly higher BESS error scores and greater sway length following L-C/R-A stimulation compared to both the baseline and L-A/R-C conditions. (4) Conclusions: Bilateral tDCS over the PPC differentially influences cortical activity and postural control depending on the stimulation polarity. Specifically, L-C/R-A stimulation was associated with impaired visual–vestibular integration and postural stability. These preliminary findings highlight the critical role of interhemispheric parietal balance in posture regulation and suggest that polarity-specific tDCS protocols may be important considerations for the future. Full article

Background: The video head impulse test (vHIT) is a standard tool for assessing semicircular canal function through vestibulo-ocular reflex (VOR) gain and corrective saccades (CS). Although reduced gain accompanied by CS typically indicates vestibular hypofunction, a paradoxical pattern—normal gain with CS—is occasionally observed, and its clinical significance remains unclear. Methods: We retrospectively analyzed 1573 patients who underwent both vHIT and bithermal caloric testing between September 2022 and September 2025. Among them, 1174 subjects with normal bilateral horizontal VOR gains (0.8–1.2) were evaluated for CS. CS were defined as at least three consistent refixation saccades on one side, verified visually. Subjects were categorized into Right-, Left-, and Bilateral-CS groups. Comparisons were made between CS(+) and CS(−) sides, as well as among groups, using paired and one-way ANOVA tests. Results: CS were identified in 46.3% (544 in 1174) of subjects with normal VOR gains, most frequently on the right side. The side showing CS exhibited significantly lower caloric responses than the contralateral side (p < 0.001). Bilateral CS were more common in older patients. Canal paresis values indicated that the CS side corresponded to the weaker caloric side, suggesting subtle unilateral hypofunction. Conclusions: Even with normal gain, the presence of CS may reflect mild vestibular asymmetry rather than a benign artifact. In addition, bilateral CS were associated with older age, suggesting a possible contribution of age-related vestibular or compensatory mechanisms. Careful control of methodological biases and integration with other vestibular tests are essential for interpretation. Full article

Background: Maintaining postural stability requires the integration of multisensory information, including visual, vestibular, and somatosensory inputs. This study aimed to investigate the effects of narrowband noise across different frequency bands on static postural balance and cortical activation in healthy adults. Methods: Twenty healthy adults participated in a repeated-measures experiment in which they maintained a tandem stance with eyes closed under four conditions: no sound, low-frequency narrowband noise (500 Hz), mid-frequency narrowband noise (2000 Hz), and high-frequency narrowband noise (5000 Hz). Static balance was assessed using center of pressure parameters, including sway length, ellipse surface, delta X, and delta Y, recorded via a pressure measurement platform. Cortical activation in the premotor cortex (PMC), frontal eye fields (FEF), superior temporal gyrus (STG), and middle temporal gyrus (MTG) was measured simultaneously using functional near-infrared spectroscopy. Results: Mid-frequency narrowband noise significantly improved postural stability, as evidenced by reductions in sway length, ellipse surface, and delta Y compared to the high-frequency and no-sound conditions (p < 0.05). In contrast, high-frequency narrowband noise consistently produced the greatest postural instability, with significantly larger ellipse surface and delta Y values (p < 0.05). Regarding cortical activation, high-frequency stimulation induced significantly greater bilateral activation in the PMC compared to low-frequency stimulation, while all auditory conditions elicited widespread activation across PMC, STG, and MTG. Conclusions: These findings suggest that the frequency characteristics of auditory stimulation exert differential neurophysiological effects on balance control. Mid-frequency narrowband noise may enhance static balance by facilitating sensorimotor integration, whereas high-frequency narrowband noise may induce PMC hyperactivation, potentially contributing to postural instability. Full article

Background: Walking is a dynamic activity that relies on inputs from the multisensory system, i.e., somatosensory, vision, and vestibular. These inputs are processed and integrated in the central nervous system to produce motor impulses for efficient walking balance. The Sensory Organization Test (SOT) is established as the gold standard for assessing sensory contributions to standing balance. However, no comparable assessments have been developed for the clinical evaluation of balance during gait. This study evaluated the Gait Sensory Interaction Test (GaitSIT), a novel virtual reality (VR)-based assessment for characterizing sensory-condition-specific changes in walking balance. Methods: The GaitSIT comprises a VR environment with a physical compliant foam walking surface that evaluates gait–balance by systematically manipulating and evaluating the sensory systems. Twenty-nine healthy young adults (mean age 24.9 ± 6.4 years) were instructed to complete 6 m walking trials under six standardized conditions (C): eyes open, eyes closed/dark scene, and rotating visual scenes on a firm surface, then repeated on a foam surface. Wearing an Oculus VR headset, participants were instructed to walk in a straight line at their preferred speed, as naturally as possible, in two test sessions on the same day, followed by a third test session 24 h later. Headset-derived sway measures, including position, velocity, and acceleration data, were recorded, and the continuous trajectory deviation angle (i.e., directional control) and sensory ratios were calculated. Linear mixed-effects models included trial-level walking speed as a covariate. Additionally, participants completed the modified Clinical Test of Sensory Interaction on Balance (mCTSIB) as a clinical standing-balance reference measure; its concurrent-validity findings will be reported separately. Results: Significant condition effects were observed for position, velocity, acceleration, and CTDA after adjustment for trial-level walking speed (all $p<0.001$), indicating that the six sensory conditions elicited distinct gait–balance responses. Significant differences relative to the baseline condition (C1) were observed across conditions C2–C6 for position, C3–C6 for velocity, and C2 and C5 for acceleration. Session effects were not significant for any primary kinematic outcome after speed adjustment. A significant condition × session interaction was observed for position ($p<0.001$), whereas velocity, acceleration, and CTDA demonstrated no significant interactions. Walking speed was significantly associated with position, acceleration, and CTDA, but not velocity. Sensory-ratio analyses revealed larger visual and vestibular ratios relative to somatosensory ratios, with the visual and vestibular ratios generally decreasing across sessions. Conclusions: GaitSIT successfully manipulated sensory conditions during overground walking and produced significant changes in gait-related sway, directional control, and sensory-ratio measures. These findings support the feasibility of GaitSIT as a portable, low-cost, and immersive assessment framework for characterizing sensory-condition-specific gait–balance responses after accounting for walking speed and providing indirect behavioral indices related to sensory reweighting. Full article

Postural control is a multilevel adaptive system that stabilizes the body in space through dynamic sensory rebalancing and predictive neuromotor regulation. This review synthesizes current data on the neural mechanisms of balance maintenance, individual strategies for integrating multisensory information, and the role of immersive virtual reality as a controlled experimental and neuromodulation platform, synthesising evidence from 73 studies across neuroscience, cognitive psychology, and VR-based rehabilitation. Particular attention is paid to the cognitive style of “field dependence/independence”, which reflects stable preferences for the dominance of visual or vestibular-proprioceptive signals and consistently predicts the selection of postural strategies. We show that traditional averaged models ignore interpersonal variability, whereas immersive VR allows for the parametric induction of sensory conflicts, quantitative assessment of sensory dependence profiles, and facilitates the study of adaptive reorganization at the cortical, brainstem, and spinal levels. The review substantiates the need to move from standardized protocols to personalized approaches in diagnostics and neurorehabilitation that consider individual patterns of input rebalancing. The integration of behavioural metrics with neurophysiological markers in a VR environment provides a foundation for developing predictive balance models and targeted training interventions. However, the translational application of VR-based approaches requires careful consideration of methodological limitations, including cybersickness, hardware latency, and ecological validity, to ensure robust and generalisable outcomes. Full article

Human spaceflight in microgravity induces profound physiological adaptations, yet its effects on the sensory system remain comparatively underexplored. While musculoskeletal and cardiovascular changes are well documented, sensory alterations pose equally important challenges to astronaut safety, performance, and post-mission recovery. Calcium ions (Ca²⁺), as universal intracellular messengers, play central roles in sensory transduction, neurotransmitter release, and adaptive signaling across all sensory modalities. Emerging evidence suggests that microgravity may influence Ca²⁺ homeostasis and Ca²⁺-dependent cellular processes, potentially affecting the functional integrity of sensory pathways. In this review, we synthesize current findings on the impact of microgravity on Ca²⁺-dependent processes in the five classical senses. Evidence from spaceflight studies, ground-based analogs, and related physiological models suggests possible alterations in taste receptor signaling, Ca²⁺-binding protein expression, mechanotransduction pathways, and vestibular function. However, direct evidence for microgravity-induced disruption of Ca²⁺ signaling remains limited for several sensory modalities. Collectively, these changes are associated with altered taste and smell perception, visual disturbances, reduced tactile sensitivity, and vestibular imbalance. By integrating both direct evidence and mechanistic hypotheses across sensory systems, this review highlights Ca²⁺ signaling as a potential unifying mechanism underlying sensory adaptation to microgravity. We further identify key knowledge gaps and discuss potential directions for developing targeted countermeasures aimed at preserving sensory function during long-duration missions. Beyond spaceflight, these insights contribute to a broader understanding of Ca²⁺-mediated sensory physiology under extreme environmental conditions. Full article

Background: The vestibular system has traditionally been interpreted within a reflex-based framework, mainly centered on gaze stabilization, vestibulo-ocular reflex pathways, and peripheral vestibular deficits. This model remains essential, but it is insufficient to explain the full spectrum of postural, perceptual, visual-motion, and self-motion complaints observed in contemporary clinical otoneurology. Objective: This conceptual narrative review examines selected representative works by Kathleen E. Cullen as landmarks in a broader transition from reflex physiology to predictive, multimodal, context-dependent, body-centered self-motion control. Methods: This is not a systematic or bibliometric review. Papers were selected because they mark distinct conceptual steps in Cullen’s work: neural encoding of self-motion, peripheral and central coding strategies, multimodal integration, active versus passive self-motion, reafference suppression, body-centered encoding, proprioceptive prediction, vestibular cerebellar internal models, sensory reweighting, and clinical translation. Synthesis: Angelaki and Cullen’s 2008 synthesis and Cullen’s subsequent work demonstrate that vestibular processing is inherently multimodal from the earliest central stages and that neural representations of self-motion depend on behavioral context. Vestibular nuclei, visual-vestibular networks, and vestibular cerebellar circuits integrate labyrinthine signals with optic flow, proprioceptive, oculomotor, motor, cerebellar, cortical, and contextual information. This architecture enables the brain to distinguish expected from unexpected motion, suppress predictable vestibular reafference during voluntary action, compute internal estimates of body motion, adapt to altered sensory reliability, and reweight sensory inputs according to task demands. Conclusions: The clinical relevance of this trajectory is substantial. Patients may show preserved high-acceleration vestibulo-ocular reflex responses while experiencing persistent instability, visually induced dizziness, defective self-motion perception, or abnormal sustained vestibular processing. Such dissociations are not paradoxical when the vestibular system is understood as a predictive, distributed, body-centered control system. Cullen’s long lesson offers a neurophysiological foundation for a modern vestibular grammar in which clinical findings are interpreted across the reflexive, perceptual, postural, visual-vestibular, sustained, and predictive domains. Full article

Motorist’s disorientation syndrome (MDS) is seen in 1 to 5% of patients in a tertiary neurotology clinic and remains an underdiagnosed pathology. It was first described in 1985 by Page & Gresty, using the term “visual vertigo”. Patients described sensations of veering or turning over while driving an automobile when visual input was restricted. This was exacerbated at high speeds, on winding roads, going down hills, or when overtaken by a vehicle. All patients in this initial study had peripheral or central neurotological abnormalities and showed exaggerated responses during optokinetic stimulation. Some sufferers considered giving up driving. The first aims of this narrative review were to delineate the symptoms of MDS as detailed in the literature, to outline precipitating situations and to discuss associated pathologies such as anxiety. The second aim was to differentiate MDS from similar syndromes, such as persistent postural-perceptual dizziness (PPPD) and motion sickness (MS). In addition, we looked at the role of vestibular assessments and discussed the involvement of the otolith organs and semicircular canals. In this review, eight publications were analyzed. MDS is related to a visual-vestibular or a visio-visual conflict and occurs in drivers (both males and females). It is associated with anxiety in 17–39% of cases. Mild vestibular-test abnormalities or exaggerated response to opto-kinetic stimulations are seen in 60–100% of cases. Between 50 and 62% of patients have a migraine history. Convergence and strabismic problems are also often seen. Symptoms usually settle after 6 ± 4 years but can persist for longer in females. MDS is multifactorial, and similar to certain forms of PPPD but different than MS. Its pathophysiology is still in question, and we support the role of the velocity storage integrator as a recent hypothesis. Treatment includes vestibular rehabilitation, virtual reality, cognitive behavioral therapies and orthoptic sessions, and the results are promising. The authors also strongly feel that future research on clarifying MDS pathology should study a wider scope of vestibular assessments to evaluate semicircular canal/otolithic function, as well as the vestibulo-ocular reflex, analyze optokinetic nystagmus time constant, and perform a systematic orthoptic examination. Full article

Background/Objectives: Persistent dizziness after the apparent resolution of an acute or episodic vestibular disorder remains a frequent and clinically challenging condition. In many patients, symptoms persist despite negative positional testing, absence of spontaneous nystagmus, and preserved high-frequency vestibular responses on video head impulse testing. This discrepancy suggests that persistent dizziness may not always be explained by incomplete recovery of a single peripheral vestibular lesion but may reflect a dissociation between transient/high-frequency vestibular responses and sustained/low-frequency or integrative vestibular processing. The aim of this study was to propose a hypothesis-generating, case-based clinical framework for interpreting this dissociation and its implications for targeted vestibular rehabilitation. Methods: This was a retrospective, hypothesis-generating, case-based clinical study derived from routine specialist neuro-otological practice. Four illustrative cases were selected because they represented distinct patterns of persistent dizziness in which preserved or near-preserved transient vestibular responses coexisted with abnormalities in sustained, otolithic, visual–vestibular, or velocity-storage-dependent processing. All patients underwent detailed clinical history assessment, bedside neuro-otological examination, and multidomain vestibular assessment according to clinical indication. The purpose of the study was not to estimate prevalence, validate diagnostic accuracy, or demonstrate treatment efficacy but to illustrate a physiology-based interpretive framework. Results: The four cases showed different patterns of time-domain dissociation. These included low-frequency integrative dysfunction without clear peripheral lateralization, incompletely compensated unilateral vestibular asymmetry, selective unilateral otolithic loss despite preserved semicircular canal high-frequency responses, and bilateral sustained vestibular hypofunction unmasked by an apparently resolved BPPV-like event. Across cases, persistent symptoms were better explained by the relationship between transient and sustained vestibular domains than by any single test result considered in isolation. Conclusions: Persistent dizziness may arise from different combinations of preserved transient vestibular responses and impaired sustained or integrative vestibular processing. The proposed framework does not introduce new vestibular tests and does not claim to validate a new diagnostic entity. Rather, it organizes established vestibular investigations within a time-domain model that may help identify clinically meaningful dissociations and guide individualized, domain-specific vestibular rehabilitation. Prospective studies with larger samples and external validation are required to determine the diagnostic and therapeutic value of this approach. Full article

This is a narrative review that explores the development of non-implantable vestibular devices designed to address postural instability, particularly in aging populations and patients with vestibular hypofunction. It establishes that balance relies on complex sensory integration and that the functional decline of this system creates a significant medical need. Three principal technological strategies are examined: sensory substitution devices, galvanic vestibular stimulation (GVS), and immersive visual feedback systems. Sensory substitution devices, which convert balance data into auditory, tactile, or electrotactile cues, demonstrate significant promise. Examples like vibrotactile belts provide feedback that reduces postural sway, enhancing stability and patient confidence. Parallel to this, GVS—using electrical currents applied to the mastoids—emerges as a potent non-invasive method to modulate vestibular pathways, improving balance control and even inducing neuroplastic changes, especially with stochastic “noisy” signals. The most recently developed devices include augmented and virtual reality technologies that offer innovative visual feedback, creating enriched rehabilitation environments that accelerate recovery by promoting sensory reweighting and neural adaptation. This review concludes that while implantable prostheses are advancing, non-invasive devices offer versatile, affordable, and complementary solutions for balance restoration. The future success of non-invasive alternatives hinges on developing more sophisticated stimulation protocols that account for the complexity of natural movement and individual patient contexts, expanding therapeutic options for vestibular disorders. Full article

Postural control relies on the integration of visual, vestibular, and somatosensory inputs under biomechanical constraints. Conventional Romberg testing provides limited quantitative insight, particularly regarding directional control and sensory dependence. Wearable inertial measurement units (IMUs) enable portable, multidimensional assessment of postural sway. Thirty healthy adults (15 females, 15 males) completed a modified Romberg protocol with systematic manipulation of stance (normal, tandem), visual condition (eyes open, eyes closed), and arm position (arms at sides, arms forward), including both left and right leading foot during tandem stance. Whole-body kinematics were recorded using a full-body IMU system comprising 17 wireless sensors. Center-of-mass (CoM) trajectories were derived from a 23-segment biomechanical model, and linear, spatial, and nonlinear sway metrics were computed. Statistical analyses were conducted using repeated-measures ANOVA, with significance set at p < 0.05. Visual deprivation significantly increased sway path length, mean sway velocity, and sway area across all stance conditions (p < 0.001). Tandem stance elicited greater mediolateral sway than normal stance (p < 0.001). Romberg ratios exceeded unity for all metrics and were significantly higher in tandem stance (p < 0.01). Arm position effects were negligible in normal stance but showed significant Vision × Arm interactions during tandem stance (p < 0.05). Leading foot position had no significant main effects. Combining a modified Romberg protocol with full-body IMU-based CoM analysis enables sensitive characterization of sensory dependence and directional postural control. Tandem stance with visual deprivation increases mediolateral postural demands under reduced base-of-support conditions, providing a more challenging context for evaluating directional postural control. Full article