Athletes who are deaf or hard-of-hearing (D/HoH) have differing postural control performance differences compared with athletes who are hearing; however, no evidence exists regarding their reliance on visual information. Therefore, the purpose of this study was to compare the visual reliance during postural control between athletes who are D/HoH and athletes who are hearing. Athletes who are D/HoH ( n = 22) and athletes who are hearing ( n = 24) completed the traditional modified clinical test of sensory interaction and balance tasks with the addition of a third visual condition using stroboscopic vision glasses. Independent t tests revealed sway velocity Romberg ratios for eyes closed/eyes open on firm, eyes closed/eyes open on foam ( p = .01), and stroboscopic vision/eyes open on foam were different between groups ( p < .05 for all). Sway area Romberg ratios were not different ( p > .05). Findings may allow health care professionals to gauge recovery from injury in athletes who are D/HoH.

IntroductionExternal continuous perturbations using a motion platform have been developed by employing either sum-of-sines (SoS) or a pseudorandom ternary sequence (PRTS) of numbers to quantify body sway evoked in the medial-lateral (ML) or anterior-posterior (AP) directions, which ultimately helps understand the human postural control system. These stimuli have been provided via pitch tilts of the motion platform for evaluations of AP balance responses or roll tilts for ML balance responses. However, little is known about whether a healthy postural control system responds to 2-dimensional (2D) perturbations similarly when the perturbation stimuli are provided in semicircular canal coordinates (i.e., right-anterior/left-posterior (RALP) and left-anterior/right-posterior (LARP)) versus roll/pitch coordinates. Stimuli provided in either set of coordinates were orthogonal in both time and space. Our 2D platform perturbations provided in RALP/LARP coordinates will have the potential to better assess the contribution of each pair of the vertical semicircular canals to postural control for individuals with dysfunction of the vertical semicircular canals.MethodsTo address this knowledge gap, we developed four different balance perturbation trajectories using sum-of-sines (SoS) signals and simultaneously provided those stimuli in (i) roll and pitch, (ii) RALP and LARP, and (iii) roll, pitch, RALP, and LARP dimensions. Center of pressure (CoP) data were collected from 24 healthy participants (40 13 years of age) on a commercially available motion platform (Virtualis Motion VR, Perault, France). A discrete Fourier transform (DFT) was applied to the CoP data to identify responses at perturbed frequencies (i.e., spectral response components).ResultsWe found that ML and AP postural responses were not significantly different when the platform perturbations were simultaneously provided in RALP/LARP coordinates versus roll/pitch coordinates.DiscussionThis finding suggests that our 2D platform perturbations in RALP/LARP coordinates allow us (1) to compare ML and AP responses evoked by RALP and LARP stimuli to existing literature showing those responses evoked by roll and pitch stimuli and (2) to characterize postural responses for individuals with sensory deficits to better isolate contributions of the vertical semicircular canals to postural control.

OBJECTIVES:The clinical differentiation of two common vestibular disorders, Meniere's disease (MD) and vestibular migraine (VM), remains challenging and is based on criteria provided by expert panels rather than the results of diagnostic tests. We therefore investigated the hypothesis that perceptual thresholds for passive motions that activate the inner ear vestibular sensors (canals, otolith organs) can be used to improve the clinical differentiation of MD and VM. DESIGN:Self-motion perceptual thresholds were measured in MD and VM patients using a multiaxis motion platform during movements that included linear translations (along the naso-occipital, interaural, and superior-inferior axes); angular rotations (in the yaw plane); and head tilts (about an earth-horizontal roll axis). Conventional vestibular testing (caloric, video head impulse testing, and cervical vestibular evoked myogenic potential) was also performed in MD and VM patients. RESULTS:MD patients demonstrated elevated superior-inferior thresholds compared with VM patients and healthy controls; and elevated roll tilt thresholds compared with VM patients, consistent with previously described changes in saccular function in MD and in central vestibular integration in VM. Standard clinical vestibular tests, in contrast, did not differ significantly between MD and VM patients, nor did they correlate with perceptual thresholds. CONCLUSIONS:Our results support the hypothesis that perceptual threshold testing could be helpful to differentiate MD from VM in clinical practice. More generally, our findings suggest that perceptual threshold testing may provide information that is not available in the standard clinical vestibular test battery, implying that perceptual threshold tests could increase the diagnostic utility of the clinical vestibular test battery.

OBJECTIVES:A growing body of evidence has linked vestibular function to the higher-order cognitive ability in aging individuals. Past evidence has suggested unique links between vestibular function and cognition on the basis of end-organ involvement (i.e., otoliths versus canals). However, past studies have only assessed vestibular reflexes despite the diversity of vestibular pathways. Thus, this exploratory study aimed to assess associations between vestibular perception and cognition in aging adults to determine potential relationships. DESIGN:Fifty adults (21 to 84 years; mean = 52.9, SD = 19.8) were included in this cross-sectional study. All participants completed a vestibular perceptual threshold test battery designed to target perception predominantly mediated by each end-organ pair and intra-vestibular integration: 1 Hz y -translation (utricle), 1 Hz z -translation (saccule), 2 Hz yaw rotation (horizontal canals), 2 Hz right anterior, left posterior (RALP), and left anterior, right posterior (LARP) tilts (vertical canals), and 0.5 Hz roll tilt (canal-otolith integration). Participants also completed standard assessments of cognition and path integration: Digit Symbol Substitution Test (DSST), Trail Making Test (TMT), and the Gait Disorientation Test (GDT). Associations were assessed using Spearman rank correlation, and multivariable regression analyses. RESULTS:For correlation analyses, DSST correlated to RALP/LARP tilt, roll tilt, and z -translation. TMT-A only correlated to z -translation, and TMT-B correlated to roll tilt and z -translation after correcting for multiple comparisons. GDT correlated to RALP/LARP tilt and y -translation. In age-adjusted regression analyses, DSST and TMT-B were associated with z -translation thresholds and GDT was associated with y -translation thresholds. CONCLUSIONS:In this cross-sectional study, we identified associations between vestibular perceptual thresholds with otolith contributions and standard measures of cognition. These results are in line with past results suggesting unique associations between otolith function and cognitive performance.

The vestibular system – the organs in our inner ear that sense head motion and gravity – contribute to self-motion perception, balance control, and several reflexive responses. Maintaining robust vestibular sensation imposes a high metabolic load; consider that the human vestibular periphery has over 100,000 hair cells requiring energy to maintain depolarization and roughly 40,000 peripheral neurons requiring energy to support an average firing rate of nearly 100 action potentials per second for each neuron. Therefore, the aim of this study was to evaluate the impact of reduced oxygen (hypoxia) on the human vestibular system. To quantify the impacts of hypoxia, vestibular function was quantified using standard forced-choice psychophysical methods to determine the smallest earth-vertical (i.e., upward/downward) translation that a seated human could reliably sense. To manipulate blood oxygenation, we controlled the O 2 content of the air that participants breathed using a Reduced Oxygen Breathing Device 2 (Environics). To quantify blood oxygenation and pulse rate, we used a standard fingertip pulse oximeter. We hypothesized that: (1) blood oxygenation would decrease when breathing air with lower oxygen content, (2) human vestibular thresholds would worsen with reduced blood oxygenation, and (3) vestibular degradation would increase as blood oxygenation decreases. All data were collected at an elevation of ~800’. On different days, 15 participants breathed air with 20.9% or 15.4% oxygen content to simulate 0’ and 8,000’ altitudes respectively. As predicted, blood oxygenation (SpO2) reduced from an average of 96.7% when participants breathed air with 20.9% oxygen to 91.4% when breathing air with 15.4% oxygen content ( F (1,11) = 148.27, p <.001, Generalized eta squared = 0.770). Earth-vertical translation thresholds were significantly higher when breathing 15.4% oxygen than 20.9% oxygen ( F (1,14) = 22.49, p <.001, Generalized eta squared = 0.096). The largest threshold increase (median 41%; mean 33%) was observed in the 3 rd threshold test conducted 30 to 45 minutes after reducing O 2 content. Further, Type II linear regression showed that thresholds degraded as blood oxygenation decreased (R = -0.29). Despite these relatively large changes in perceptual precision, subjects reported no spatial disorientation illusions. These results show that vestibular thresholds were both significantly and substantively impacted at a simulated altitude of 8,000’. The significant correlation showing increasing thresholds with decreasing SpO2 suggests that decreases in tissue oxygenation may cause an increase in vestibular thresholds. These findings are noteworthy because the mild hypoxia condition was designed to match the cabin pressurization required in the US by the FAA for commercial flights. These results suggest that many of us who have flown in a commercial jet may have temporarily experienced degraded vestibular function. Behavioral impacts remain to be understood, but vestibular precision appears to be a harbinger of human hypoxia. Support provided by the Office of Naval Research (ONR) via a Multidisciplinary University Research Initiative grant (MURI N00014-20-1-2163). This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Purpose/hypothesisHomeostatic plasticity is an innate self-regulatory process that functions to stabilize neural excitability in response to sensory perturbations. The purpose of this study was to investigate homeostatic plasticity in vestibular perceptual responses by measuring changes in vestibular perceptual thresholds after exposure to passive whole-body self-motion stimuli (vestibular conditioning). We hypothesized that small amplitude stimuli (i.e., subthreshold conditioning) would cause a decrease in thresholds, whereas large amplitude stimuli (i.e., suprathreshold conditioning) would cause an increase in thresholds.MethodsOne-Hz yaw rotation vestibular perceptual thresholds were measured before and immediately after 20-min blocks of passive whole-body motion (i.e., conditioning) in a cohort of 12 healthy adults (27 ± 8.19 years; 10 female). The conditioning stimuli consisted of 1 Hz sinusoidal motions and included (a) subthreshold yaw rotations with a peak velocity equal to 57.4% of the baseline threshold (T0.57x), (b) suprathreshold yaw rotations with a peak velocity equal to 200% of the baseline threshold (T2x), or (c) a sham stimulus consisting of 0.1 mm/s interaural translations (TSham). A subset of the group returned to complete an additional subthreshold yaw rotation condition with a peak velocity equal to 20% of the baseline threshold (T0.2x). A cohort of 5 individuals (1 female) with chronic unilateral vestibular hypofunction participated in the T0.57x subthreshold conditioning stimulus.ResultsYaw rotation thresholds were significantly increased after suprathreshold conditioning (1.36 ± 0.75°/s, p = 0.004), increasing an average of 31.75% relative to baseline (1.05 ± 0.52°/s). However, counter to our hypothesis, yaw rotation thresholds were not significantly lowered in our healthy adult population after either of the two subthreshold conditioning tasks (T0.57x: 1.11 ± 0.62°/s, p = 0.61; T0.2x: 1.20 ± 0.69°/s, p = 0.385). Yet, four out of the five participants with chronic unilateral vestibular hypofunction displayed an improvement in perceptual thresholds (Range of 10.32–29.14%) following the T0.57x subthreshold conditioning task.ConclusionThese data suggest (1) that 20 min periods of passive whole-body motion are sufficient to modify vestibular perception and (2) that the impact of subthreshold conditioning on perceptual thresholds may depend on the baseline integrity of the vestibular system.

This chapter delves into the multifaceted role of the vestibular system in sensory perception, balance, and spatial orientation. It highlights the system's evolutionary roots, showing its significance across vertebrates and its contributions to human locomotion and cognition. Spatial orientation involves three key modalities—angular motion, linear motion, and tilt perception—sensed by specialized vestibular organs such as semicircular canals and otolith organs. The chapter then explores multisensory integration, where vestibular inputs merge with visual, somatosensory, and motor signals to support dynamic perception and reflexes like the vestibulo-ocular reflex, which stabilizes vision during head motion. Vestibular system dysfunction causes symptoms such as dizziness, disorientation, and balance deficits, highlighting its vital but often unnoticed role in everyday life.

This chapter explores the mechanisms enabling the brain to perceive and recognize objects, starting from simple visual features to complex object identification. It details the transition from early processing of edges and lines in the primary visual cortex (V1) to advanced analysis in the extrastriate and inferotemporal regions, highlighting the “what” and “where” pathways that distinguish object identity from spatial location. Midlevel vision addresses challenges in object perception, such as recognizing occluded or ambiguous objects, by organizing basic visual inputs into coherent entities using principles like edge grouping and figure-ground assignment. The chapter extends to object recognition, emphasizing how stored memories and neural plasticity facilitate identifying diverse stimuli, including faces and complex shapes. By combining computational models and experimental findings, the chapter underscores the sophisticated yet efficient strategies of the visual system in deciphering a dynamic visual world.

Vestibular perceptual thresholds quantify sensory noise associated with reliable perception of small self-motions. Previous studies have identified substantial variation between even healthy individuals’ thresholds. However, it remains unclear if or how an individual’s vestibular threshold varies over repeated measures across various time scales (repeated measurements on the same day, across days, weeks, or months). Here, we assessed yaw rotation and roll tilt thresholds in four individuals and compared this intra-individual variability to inter-individual variability of thresholds measured across a large age-matched cohort each measured only once. For analysis, we performed simulations of threshold measurements where there was no underlying variability (or it was manipulated) to compare to that observed empirically. We found remarkable consistency in vestibular thresholds within individuals, for both yaw rotation and roll tilt; this contrasts with substantial inter-individual differences. Thus, we conclude that vestibular perceptual thresholds are an innate characteristic, which validates pooling measures across sessions and potentially serves as a stable clinical diagnostic and/or biomarker.

Our ability to maintain our balance plays a pivotal role in day-to-day activities. This ability is believed to be the result of interactions between several sensory modalities including vision and proprioception. Past research has revealed that different aspects of vision including relative visual motion (i.e., sensed motion of the visual field due to head motion), which can be manipulated by changing the viewing distance between the individual and the predominant visual cues, have an impact on balance. However, only a small number of studies have examined this in the context of virtual reality, and none examined the impact of proprioceptive manipulations for viewing distances greater than 3.5 m. To address this, we conducted an experiment in which 25 healthy adults viewed a dartboard in a virtual gymnasium while standing in narrow stance on firm and compliant surfaces. The dartboard distance varied with three different conditions of 1.5 m, 6 m, and 24 m, including a blacked-out condition. Our results indicate that decreases in relative visual motion, due to an increased viewing distance, yield decreased postural stability - but only with simultaneous proprioceptive disruptions.

IntroductionPseudorandom balance perturbations use unpredictable disturbances of the support surface to quantify reactive postural control. The ability to quantify postural responses to a continuous multidirectional perturbation in two orthogonal dimensions of sway (e.g., AP and ML) has yet to be investigated.MethodsWe developed a balance perturbation paradigm that used two spectrally independent sum of sinusoids signals (SoS1, SoS2), one for each orthogonal dimension of tilt (roll and pitch), to deliver a two-dimensional (2D) balance perturbation. In a group of 10 healthy adults we measured postural sway during 2D perturbations, as well as for each of the two individual 1D perturbation components.ResultsWe found that during 2D perturbations, spectral peaks in the sway response were larger at the perturbed frequencies when compared to (1) the adjacent non-perturbed frequencies and (2) the frequencies contained within the orthogonal, spectrally independent perturbation signal. We also found that for each of the two spectra (SoS1, SoS2), the magnitude and timing of the sway response relative to the platform disturbance was similar when measured during 1D and 2D conditions.DiscussionThese data support that our novel 2D SoS perturbation test was able to evoke ML and AP postural responses that were (1) specific to the roll and pitch perturbations, respectively, and (2) similar to the responses provoked by individual 1D perturbations.

Our ability to maintain our balance plays a pivotal role in day-to-day activities. This ability is believed to be the result of interactions between several sensory modalities including vision and proprioception. Past research has revealed that different aspects of vision including relative visual motion (i.e., sensed motion of the visual field due to head motion), which can be manipulated by changing the viewing distance between the individual and the predominant visual cues, have an impact on balance. However, only a small number of studies have examined this in the context of virtual reality, and none examined the impact of proprioceptive manipulations for viewing distances greater than 3.5 m. To address this, we conducted an experiment in which 25 healthy adults viewed a dartboard in a virtual gymnasium while standing in narrow stance on firm and compliant surfaces. The dartboard distance varied with three different conditions of 1.5 m, 6 m, and 24 m, including a blacked-out condition. Our results indicate that decreases in relative visual motion, due to an increased viewing distance, yield decreased postural stability - but only with simultaneous proprioceptive disruptions.

Although perceptual thresholds have been widely studied, vestibuloocular reflex (VOR) thresholds have received less attention, so the relationship between VOR and perceptual thresholds remains unclear. We compared the frequency dependence of human VOR thresholds to human perceptual thresholds for yaw head rotation in both upright ("yaw rotation") and supine ("yaw tilt") positions, using the same human subjects and motion device. VOR thresholds were generally a little smaller than perceptual thresholds. We also found that horizontal VOR thresholds for both yaw rotation about an Earth-vertical axis and yaw tilt (yaw rotation about an Earth-horizontal axis) were relatively constant across four frequencies (0.2, 0.5, 1, and 2 Hz), with little difference between yaw rotation and yaw tilt VOR thresholds. For yaw tilt stimuli, perceptual thresholds were slightly lower at the lowest frequency and nearly constant at all other (higher) frequencies. However, for yaw rotation, perceptual thresholds increased significantly at the lowest frequency (0.2 Hz). We conclude 1) that VOR thresholds were relatively constant across frequency for both yaw rotation and yaw tilt, 2) that the known contributions of velocity storage to the VOR likely yielded these VOR thresholds that were similar for yaw rotation and yaw tilt for all frequencies tested, and 3) that the integration of otolith and horizontal canal signals during yaw tilt when supine contributes to stable perceptual thresholds, especially relative to the low-frequency perceptual thresholds recorded during yaw rotation.NEW & NOTEWORTHY We describe for the first time that human VOR thresholds differ from human forced-choice perceptual thresholds, with the difference especially evident at frequencies below 0.5 Hz. We also report that VOR thresholds are relatively constant across frequency for both yaw rotation and yaw tilt. These findings are consistent with the idea that high-pass filtering in cortical pathways impacts cognitive decision-making.

This chapter explains the mechanisms underlying color perception, starting with the basic principles where color arises from the interaction between light wavelengths and the nervous system. It outlines three essential steps: detection, where photoreceptors in the eye convert light into signals; discrimination, where the nervous system distinguishes between different wavelengths; and appearance, where perceived colors are assigned to objects and remain stable under various conditions. The chapter then highlights individual differences in color perception, from genetic factors to cultural influences, and explores the unique role of color in everyday vision, including its adaptive significance for tasks like recognizing objects or signals. Finally, it considers broader questions, such as the purpose of color vision and its ability to transform the physical wavelengths of light into the rich, subjective experience of a colorful world. These insights emphasize how biological and perceptual processes intertwine to create our vibrant visual reality.

Vestibular contributions to linear motion (i.e., translation) perception mediated by the otoliths have yet to be fully characterized. To quantify the maximal extent that non-vestibular cues can contribute to translation perception, we assessed vestibular perceptual thresholds in two patients with complete bilateral vestibular ablation to compare to our data in 12 young (< 40 years), healthy controls. Vestibular thresholds were assessed for naso-occipital (“ x -translation”), inter-aural (“ y -translation”), and superior-inferior (“ z -translation”) translations in three body orientations (upright, supine, side-lying). Overall, in our patients with bilateral complete vestibular loss, thresholds were elevated ~ 2–45 times relative to healthy controls. No systematic differences in vestibular perceptual thresholds were noted between motions that differed only with respect to their orientation relative to the head (i.e., otoliths) in patients with bilateral vestibular loss. In addition, bilateral loss patients tended to show a larger impairment in the perception of earth-vertical translations (i.e., motion parallel to gravity) relative to earth-horizontal translations, which suggests increased contribution of the vestibular system for earth-vertical motions. However, differences were also noted between the two patients. Finally, with the exception of side-lying x -translations, no consistent effects of body orientation in our bilateral loss patients were seen independent from those resulting from changes in the plane of translation relative to gravity. Overall, our data confirm predominant vestibular contributions to whole-body direction-recognition translation tasks and provide fundamental insights into vestibular contributions to translation motion perception.

This study examined the difference in the dynamic visual acuity test (DVAT) between collegiate athletes who are deaf or hard-of-hearing (D/HoH) (n = 38) and university club-level athletes who are hearing (n = 38). Dynamic visual acuity was assessed using the Bertec Vision Advantage (Bertec® Corporation, Columbus, Ohio, USA). No statistically significant differences between athletes who are D/HoH and who are hearing were found in DVAT for leftward (χ2 = 0.71, p = 0.40) or rightward (χ2 = 0.04, p = 0.84) head yaw rotation around an earth vertical axis. Dynamic visual acuity was similar for athletes regardless of hearing status. Baseline DVAT data may be of use for post-injury management of athletes who are D/HoH.

Background:Persistent postural perceptual dizziness (PPPD) is a common cause of chronic dizziness and imbalance. Emerging evidence suggests that changes in quantitative measures of postural control may help identify individuals with PPPD, however, traditional linear metrics of sway have yielded inconsistent results. Methodologies to examine the temporal structure of sway, including recurrent quantification analysis (RQA), have identified unique changes in dynamic structure of postural control in other patient populations. This study aimed to determine if adults with PPPD exhibit changes in the dynamic structure of sway and whether this change is modulated on the basis of available sensory cues.Methods:Twelve adults diagnosed with PPPD and twelve age-matched controls, completed a standard battery of quiet stance balance tasks that involved the manipulation of visual and/or proprioceptive feedback. For each group, the regularity and complexity of the CoP signal was assessed using RQA and the magnitude and variability of the CoP signal was quantified using traditional linear measures.Results:An overall effect of participant group (i.e., healthy controls vs. PPPD) was seen for non-linear measures of temporal complexity quantified using RQA. Changes in determinism (i.e., regularity) were also modulated on the basis of availability of sensory cues in patients with PPPD. No between-group difference was identified for linear measures assessing amount and variability of sway.Conclusions:Participants with PPPD on average exhibited sway that was similar in magnitude to, but significantly more repeatable and less complex than, healthy controls. These data show that non-linear measures provide unique information regarding the effect of PPPD on postural control, and as a result, may serve as potential rehabilitation outcome measures.

One's ability to maintain their center of mass within their base of support (i.e., balance) is believed to be the result of multisensory integration. Much of the research in this literature has focused on integration of visual, vestibular, and proprioceptive cues. However, several recent studies have found evidence that auditory cues can impact balance control metrics. In the present study, we sought to better characterize the impact of auditory cues on narrow stance balance task performance with different combinations of visual stimuli (virtual and real world) and support surfaces (firm and compliant). In line with past results, we found that reducing the reliability of proprioceptive cues and visual cues yielded consistent increases in center-of-pressure (CoP) sway metrics, indicating more imbalance. Masking ambient auditory cues with broadband noise led to less consistent findings; however, when effects were observed they were substantially smaller for auditory cues than for proprioceptive and visual cues - and in the opposite direction (i.e., masking ambient auditory cues with broadband noise reduced sway in some situations). Additionally, trials that used virtual and real-world visual stimuli did not differ unless participants were standing on a surface that disrupted proprioceptive cues; disruption of proprioception led to increased CoP sway metrics in the virtual visual condition. This is the first manuscript to report the effect size of different perturbations in this context, and the first to study the impact of acoustically complex environments on balance in comparison to visual and proprioceptive contributions. Future research is needed to better characterize the impact of different acoustic environments on balance.

Context Because of the close proximity of the cochlea, vestibular apparatus, and shared neurovascular structures, the static postural control of athletes who are deaf or hard of hearing (D/HoH) may be different from that of athletes who are hearing. Limited research is available to quantify differences between these athletes. Objective To determine the effect of hearing status and stance condition on the static postural control of athletes. Design Cross-sectional study. Setting Athletic training facilities. Patients or Other Participants Fifty-five collegiate varsity athletes who were D/HoH (age = 20.62 ± 1.80 years, height = 1.73 ± 0.08 m, mass = 80.34 ± 18.92 kg) and 100 university club athletes who were hearing (age = 20.11 ± 1.59 years, height = 1.76 ± 0.09 m, mass = 77.66 ± 14.37 kg). Main Outcome Measure(s) Participants completed the Modified Clinical Test of Sensory Interaction and Balance on a triaxial force plate. Anteroposterior and mediolateral (ML) center-of-pressure (CoP) velocity, anteroposterior and ML CoP amplitude root mean square, and 95% ellipse sway area were calculated. Results Athletes who were D/HoH had a larger CoP velocity, larger ML root mean square, and larger sway area than those who were hearing (P values < .01). A significant main effect of stance condition was observed for all postural control variables (P values < .01). Conclusions During the Modified Clinical Test of Sensory Interaction and Balance, athletes who were D/HoH demonstrated a larger sway area compared with athletes who were hearing. Therefore, individualized baseline assessments of static postural control may be warranted for athletes who are D/HoH as opposed to comparisons with existing normative data.

OBJECTIVE:To assess vestibular (i.e., passive self-motion) perception in patients diagnosed with persistent postural-perceptual dizziness (PPPD). STUDY DESIGN:Case-controlled, cross-sectional, observational investigation. SETTING:Single-center laboratory-based study. PATIENTS:Thirteen patients with PPPD, 13 age-matched healthy control volunteers. Of those with PPPD, eight had co-occurring vestibular migraine (VM). INTERVENTIONS:All participants completed a vestibular threshold test battery reflecting perception with predominant inputs from ( a ) the otoliths (1-Hz interaural y -axis translation, 1-Hz superior-inferior z -axis translation), ( b ) the semicircular canals (2-Hz yaw rotation, 2-Hz tilts in the planes of the vertical canal pairs), and ( c ) and canal-otolith integration (0.5-Hz roll tilt). MAIN OUTCOME MEASURES:Direction-recognition thresholds for each vestibular threshold test condition. RESULTS:Across all patients with PPPD, higher thresholds for superior-inferior z -translations thresholds in comparison to age-matched healthy control participants were identified ( p < 0.001). Those patients with co-occurring VM and PPPD (PPPD/+VM) displayed significantly higher z -translation thresholds ( p = 0.006), whereas patients with PPPD without VM (PPPD/-VM) displayed significantly higher roll tilt thresholds ( p = 0.029). CONCLUSIONS:Patients with PPPD did not display a global worsening of passive self-motion perception as quantified by vestibular perceptual thresholds. Instead, patients with PPPD displayed elevated thresholds for only roll tilt and z -translation thresholds, with the relative change in each threshold impacted by the co-occurrence of VM. Because both z -translation and roll tilt motions are reliant on accurate gravity perception, our data suggest that patients with PPPD may exhibit impaired processing of graviceptive cues.