Feasibility Assessment of Noninvasive Vestibular System Masking for Recalcitrant Pediatric Vertigo Management

Abstract

Objective:

In pediatric populations, untreated vertigo can be detrimental to overall health and quality of life. Current therapies for vestibular dysfunction include medical management and vestibular physical therapy. Noninvasive alternatives, such as vestibular stimulation, are gaining more attention. For this investigation, we trialed a novel study device utilizing noninvasive vestibular system masking (nVSM), which imparts low-frequency vibrations to the skull to alleviate common symptoms. In this pilot case series, we sought to determine the impact induced by this device as a treatment option.

Methods:

Prospective pilot study at a tertiary, stand-alone children’s hospital. Adolescents with persistent vertigo were tested in a computerized dynamic posturography (CDP) machine, which created real-world simulations to induce dizziness. CDP was completed twice during the testing appointment: once without the nVSM for a baseline level and then with the device. Symptom severity was assessed via the Pediatric Vestibular Symptom Questionnaire (PVSQ).

Results:

Five female patients with a mean age of 15.6 years were recruited into the trial. We observed a trend that might suggest differential responses across patient types, though a small sample size precludes any definitive conclusions. Mean PVSQ scores in the pre- and posttesting periods demonstrated decreased symptom severity (2.02-1.32). Although 2 participants reported slightly worsened scores, most expressed enthusiasm for continued access to the device.

Conclusion:

In this uncontrolled pilot study, patients reported symptom reductions while using the device; however, controlled studies are needed to distinguish therapeutic effects from placebo responses. The device was well tolerated and may function as a low-risk, noninvasive alternative to current therapies. Future work will continue to evaluate the device’s effectiveness. In this pilot study, for patients with no other options, the nVSM based on low-frequency inner ear stimulation has the potential to serve as a valuable and immediate treatment for symptom relief.

Introduction

The vestibular system consists of a crucial set of structures intricately involved in the maintenance of balance and spatial orientation. Dysfunction of this system can result in a variety of symptoms, including dizziness, vertigo, nausea, gaze instability, and a pervasive sense of unsteadiness. ¹ Vestibular dysfunction can arise from either peripheral or central causes, and symptoms can manifest either suddenly or progress gradually. ¹

Central causes of vestibular dysfunction refer to deficiencies of the central vestibular system in processing and interpreting incoming sensory signals and generating outgoing signals. ² In contrast, peripheral causes relate to the anomalies of the vestibular system itself, as seen in vestibular neuritis or benign paroxysmal positional vertigo.^{2 -5} While vestibular dysfunction has been well-characterized in adults,^{6 -8} it also significantly affects children, often leading to disrupted daily activities, missed school, and reduced quality of life.^9,10

Pediatric vertigo is commonly caused by benign paroxysmal positional vertigo and vestibular migraine, and some cases remain difficult to treat. ¹¹ Current treatments for vestibular dysfunction include medications, vestibular rehabilitation therapy, and lifestyle modifications.^2,3,12,13 Medications either modulate the symptom intensity, as in vestibular suppressants, antiemetic medications, and migraine therapies, or impact the underlying disease, as in calcium channel antagonists. ¹² Certain medications, especially sedatives, can affect the rate of adjustment or compensation for damage of the vestibular system, providing relief yet slowing the brain’s ability to adapt and recover from vestibular damage by suppressing neural activity. ³ Vestibular therapy is also an option; rehabilitation for vestibular dysfunction is tailored to the presenting symptoms, with main objectives of vestibular therapy being to enhance abilities to adapt, habituate, and substitute. ³ Adaptation refers to inducing long-term changes in the nervous system’s response to head movements. Exercises to improve adaptation include gaze stability, where the head moves while maintaining a focus on 1 visual target. Habituation pertains to a repeated exposure to a stimulus that evokes symptoms to reduce the response, and substitution relies on other sensory cues to stabilize gaze and balance. ³ While noninvasive treatments such as vestibular rehabilitation therapy exist, they can be time-intensive, require consistent participation, and may not be effective for all patients. ⁴

Beyond these traditional treatments, noninvasive vestibular stimulation has gained attention as a potential therapeutic option. A noninvasive vestibular system masking (nVSM) device was developed by Otolith Labs (Washington, DC, USA) to mitigate symptoms of vertigo by delivering low-frequency vibrations (30-70 Hz) to the skull. ¹⁴ The proposed mechanism is based on the stochastic resonance phenomenon, in which the addition of low-level noise enhances the brain’s ability to process weak or distorted signals. Specifically, the device is believed to function by continuously resetting the central velocity storage of the vestibular pathway, a feedback loop between the nodulus/uvula of the cerebellum and the inferior vestibular nucleus.^{14 -16} Therefore, the nVSM device likely functions through several complementary mechanisms: (1) stochastic resonance ¹⁷ ; (2) disruption of abnormal signals through bone-conducted vibration that reaches the vestibular end organs ¹⁸ ; (3) continuous resetting of central velocity storage mechanisms, thereby reducing conflicting inputs. ¹⁹ Further physiological studies are needed to confirm these hypotheses.

Prior research in adults has demonstrated that vestibular stimulation can mitigate symptoms of motion sickness, ²⁰ seasickness, ²¹ and balance impairments. ²² Additionally, studies in virtual reality environments have demonstrated that vestibular stimulation can extend tolerable exposure durations by reducing nausea. ³ These findings suggest that vestibular stimulation in adults may reduce symptoms associated with vestibular dysfunction. However, its application in pediatric populations remains unexplored. It remains unknown whether vestibular stimulation would be equally effective in the pediatric population as in the adult population, whether pediatric patients would tolerate vestibular stimulation similarly, or whether the therapeutic effects of a noninvasive vestibular stimulation device would differ in pediatric patients. Given that vestibular dysfunction in children can significantly impact their daily activities, school performance, and quality of life, identifying effective, noninvasive interventions is of particular importance.^{23 -25} For this pilot case series, we trialed the novel nVSM device aimed to immediately offer symptom alleviation through low-frequency vibrations to the skull. By expanding prior research into the pediatric population, we aim to assess its feasibility, efficacy, and role as an intervention for children experiencing recalcitrant vertigo.

Device and Setup

The device consists of a headband, a precisely calibrated vibrating transducer, and a control case housing the printed circuit board, battery, and user controls (Figure 1). The transducer, positioned behind the right mastoid, delivers nearly inaudible vibrations at frequencies ranging between 50 and 65 Hz, with force levels between 0.20 and 0.80 Newtons. ¹⁵ The placement of vibration stimuli on the mastoid process has been shown to influence vestibular responses, ¹⁴ supporting the rationale for our device’s positioning. The vibrations are powered by an electromagnetic coil, generating a sinusoidal signal transmitted through a soft foam pad for user comfort, with the transducer secured with an adjustable headband. The device offers 4 adjustable power levels, allowing for customization based on individual preferences. ¹⁵

Figure 1.

Otolith Labs (Washington, DC, USA) device description

Materials and Methods

After obtaining Children’s National Institutional Review Board approval, patients undergoing vestibular evaluation were invited to participate in this study, conducted between December 2022 and June 2023. Written informed consent from patients’ legally authorized representatives was obtained. All patients underwent comprehensive vestibular assessment at Children’s National Hospital prior to enrollment, which included videonystagmography with caloric testing, vestibular-evoked myogenic potentials, video head impulse testing, and rotary chair testing, where clinically indicated ²⁶ (Table 1). Patients with primarily psychogenic dizziness were not candidates for this particular intervention. Patients lacked benefit from other treatments/interventions, such as vestibular physical therapy and medication (Table 2).

Table 1.

Central and Vestibular Test Outcomes and Corresponding Diagnoses. Columns Specify Abnormal or Normal Results of Central and Vestibular Tests, and Diagnosis Post-Clinical Vestibular Assessment.

ID	Central	Vestibular	Diagnosis
1	Normal	Abnormal	Bilateral vestibular hypofunction
2	Normal	Abnormal	Right vestibular hypofunction
3	Abnormal	Abnormal/normal	Right superior vestibulocochlear nerve dysfunction
4	Abnormal	Abnormal	Central dysfunction with slight right hypofunction
5	Abnormal	Abnormal	Abnormal central and vestibular dysfunction, bilateral

Table 2.

General Clinical Features of Subjects. Columns Include Participant ID, Sex, Age (Years), Symptom Duration (Months), Presumed Etiology of Vestibular Symptoms, and Previous Treatments Received. All Participants Were Female, Aged 15 to 17 years, With a Range of Vestibular Conditions and Prior Interventions.

ID	Sex	Age (y)	Symptom duration (mo)	Presumed etiology	Previous treatment
1	F	17	8	Tooth extraction	Vestibular physical therapy, migraine medication
2	F	16	18	No provocation	Vestibular physical therapy, migraine medication
3	F	15	5	Vestibular schwannoma	Migraine medication
4	F	15	18	COVID-19 infection	Migraine medication
5	F	15	7	Midline cerebellar pilocytic astrocytoma	Vestibular physical therapy

Patients were tested in the computerized dynamic posturography (CDP) machine, a quantitative assessment of balance function that measures a patient’s ability to maintain postural stability with sensory conditions. ²⁷ The system includes a force plate platform that can move while recording body sway, along with a visual surround that creates realistic environmental simulations. All patients participated in a testing scenario simulating navigation through a busy grocery store aisle. Throughout the test, patients were instructed to avoid obstacles by shifting their weight to the right or left.

The nVSM device was used in a single assessment session lasting 45 minutes. Before each testing session, proper positioning of the nVSM device was verified by the investigator. Patients were given a 2 minute familiarization period with the device before formal testing to adjust to the sensation. CDP was standardized across participants; each CDP testing condition (with and without the device) lasted ~3 minutes, with a 5 minute rest period between conditions: baseline, without the device, and intervention, with the device activated. Patients’ nVSM devices were initially set at power level 2 (of 4), with participants allowed to adjust the setting for comfort within a therapeutically effective range. All patients selected either level 2 or 3, corresponding to a vibration frequency of ~60 Hz.

Patients were administered the Pediatric Vestibular Symptom Questionnaire (PVSQ), a 10-item validated instrument assessing vestibular symptoms in pediatric populations. ²⁸ Items evaluate frequency of symptoms such as spinning sensations, unsteadiness, nausea, and visual disturbances on a 4-point scale (0 = never, 1 = almost never, 2 = sometimes, 3 = most of the time). ²⁸ Higher PVSQ scores indicate higher severity of symptoms. Demographic (age, sex) and clinical data (testing results, previous treatments) were recorded. Descriptive statistics were performed with GraphPad (Prism, 2022). Nonparametric analysis (Wilcoxon signed-rank test) was used given our small sample size.

Patient Selection

During the study period, we screened 12 pediatric patients with persistent vertigo symptoms from our vestibular clinic. Of these, 7 patients met our inclusion criteria of (1) dizziness or imbalance with unclear etiology after initial evaluation, (2) previous comprehensive vestibular testing, and (3) inadequate response to standard treatments including vestibular physical therapy and/or medication. Two eligible patients declined participation due to scheduling conflicts, resulting in our final sample of 5 participants, all of whom happened to be female adolescents.

Exclusion criteria included (1) inability to stand independently for CDP testing, (2) acute vestibular crisis requiring immediate intervention, (3) primary psychogenic dizziness, and (4) cognitive impairment preventing reliable symptom reporting. The predominance of female adolescents in our sample reflects the demographic profile of pediatric vestibular patients at our center during the recruitment period, though this distribution may not be representative of the broader pediatric vestibular population.

Results

Five patients were recruited into this study, all of whom were female. Their mean age was 15.6 years. The patients were symptomatic for at least 5 months and presented with both organic and/or inorganic lesions causing peripheral or central vestibular dysfunction (Tables 1 and 2). Findings were mixed, but promising. Four out of 5 (80%) patients reported alleviation of symptoms from their baseline condition while wearing the nVSM device, as reflected in their PVSQ scores (Table 3 and Figure 2). Descriptive statistics demonstrated a mean reduction in symptom severity following device use. Mean PVSQ scores decreased from 2.02 ± 0.19 preintervention to 1.32 ± 0.80 postintervention. Median scores similarly declined from 2.11 (Interquartile range (IQR): 2.00-2.11) preintervention to 1.00 (IQR: 0.80-1.90) postintervention. Most patients expressed interest in continued access to the device after the trial period.

Table 3.

Patient Mean PVSQ Scores Pre- and Post-nVSM Device Trial. Scores Are Expressed as Mean ± Standard Deviation for Each Participant. A Paired Wilcoxon Signed-Rank Test Did Not Reach Statistical Significance (P = .125), but the Moderate-to-Large Effect Size (r = 0.69) Indicates a Consistent Direction of Improvement Across Participants.

ID	Mean score pretrial	Mean score posttrial	Effect size, P value
1	2.200 (±0.632)	2.400 (±0.699)	0.69, .125
2	2.111 (±0.333)	1.000 (±0.789)
3	1.700 (±0.483)	0.500 (±0.527)
4	2.000 (±0.816)	1.000 (±0.943)
5	2.111 (±0.782)	1.900 (±0.568)

Abbreviations: nVSM, noninvasive Vestibular System Masking; PVSQ, Pediatric Vestibular Symptom Questionnaire.

Figure 2.

Change in PVSQ scores pre- and postintervention. Gray circles represent individual patient mean scores at pre- and postintervention, connected by gray lines to show each participant’s score trajectory. Black circles indicate the group mean at pre- and postintervention. The overall trend, being a decrease in symptom score postintervention, is visually represented by a black line connecting mean scores pre- and postintervention. PVSQ, Pediatric Vestibular Symptom Questionnaire.

Baseline PVSQ scores in this cohort were comparable to previously published data for children with vestibular disorders, in whom mean scores range from ~1.7 to 2.2 and exceed the established symptomatic cut-off of 0.68. ²⁸ Following device use, postintervention scores were closer in value to those reported in children without vestibular symptoms (a score at or below 0.68), although mean scores remained within the abnormal range.

A paired, nonparametric Wilcoxon signed-rank test was used to estimate the magnitude of within-subject change. While this comparison did not reach statistical significance (W = 1.0, P = .125), the associated effect size was moderate-to-large (rank-biserial correlation r = 0.69), indicating a consistent direction of symptom improvement across participants despite our small sample size.

Discussion

This pilot study offers early insight into the potential use of a nVSM device for managing persistent vertigo in children. Dizziness and imbalance have been reported to be prevalent in 0.45% to 15% of children. ²⁹ Current interventions to improve the vestibular systems (ie, pharmacological management and vestibular therapy) are limited, time demanding, and time-dependent. ⁴ Vestibular therapy, although noninvasive, is dependent on active participation, attention, and following directions, which can be challenging for young children. ³⁰ As a result, adherence and therapeutic benefit may be reduced in pediatric populations. A noninvasive device that requires minimal active participation may therefore offer a practical adjunct or alternative to existing therapies.

The study represents the first application of nVSM technology in patients under 18 years of age, providing initial safety and feasibility data in the pediatric population. Across a diverse set of clinical presentations, patients reported symptom alleviation when wearing the device. Positive subjective feedback suggests that not only was the device well tolerated but also that it may fill an unmet need for alternative noninvasive symptom management.

Our study also generates preliminary efficacy signals that can inform power calculations for future trials. Interestingly, children with longer symptom duration or more complex vestibular profiles appeared to find greater benefit with the device. The heterogeneity of our patient population, while a limitation, provides valuable insights into which patient subtypes might benefit most from this intervention, suggesting those with central or bilateral hypofunction may be particularly responsive.

This pilot study has several limitations. First, analysis is limited by a small sample size. A study with more children will allow for a more robust statistical analysis and a greater understanding of the extent of symptom improvement. Given the small sample size of this pilot study, statistical analyses should be considered exploratory, as the primary value of these results lies in identifying potential trends for future investigation. Our sample also consisted exclusively of female adolescents (mean age 15.6 years), limiting generalizability to males and younger pediatric populations. Furthermore, although all participants underwent comprehensive vestibular assessment, a psychiatric consultation was not included in the protocol. We recognize that pediatric dizziness may be associated with underlying psychiatric conditions, including depression. ³¹ Future studies will screen patients for psychiatric comorbidities to better characterize their potential contribution to symptom presentation. Second, there was no recorded objective measure of symptom alleviation; the data are self-reported by children. While CDP testing was conducted, we did not collect objective metrics such as equilibrium scores, sway parameters, or balance-loss events. This would have allowed us to corroborate self-reported symptoms with quantitative measurements. Future studies will systematically capture and analyze these objective parameters to provide more robust evidence of effect.

We also recognize that a sequential test protocol (baseline then device testing) could introduce habituation that could contribute to symptom improvement. This pilot study provides preliminary data that must be validated through larger, sham-controlled randomized controlled trials to establish efficacy and distinguish therapeutic effects from expectation or test–retest phenomena. The pilot study does not include a control group, limiting our ability to isolate the technology’s true therapeutic response from placebo response or natural symptom variability. Future studies incorporating randomized controlled trials would be helpful to determine whether symptom improvement is due to the device’s mechanism of action or nonspecific effects, such as expectation or novelty. The lack of long-term follow-up also leaves open the question of whether short-term or transient symptom relief translates into long-term benefit. Future work should focus on objective outcome measures, broader sample sizes, and patient demographics.

Furthermore, we recognize the limitation of using the PVSQ, a retrospective instrument designed to assess symptoms over the past month, to detect immediate changes during a single session. The observed changes may reflect momentary subjective impressions rather than true symptom modification. This is supported by an inconsistent response pattern, with 2 patients showing slight worsening of scores. In future studies, we will incorporate measures specifically designed for acute assessment, such as Visual Vertigo Analog Scales for dizziness severity, ³² and extend the follow-up period to better evaluate the long-term effects of the device using the PVSQ in its intended timeframe.

Additionally, neither participants nor investigators were blinded to the intervention, and the testing sequence (baseline followed by device) was not randomized, introducing potential expectancy and order effects. Future studies should incorporate indistinguishable sham controls and randomized testing sequences.

Lastly, although the device was well tolerated by the patients enrolled in the study, issues of practicality and wearability must be noted. Adolescents may be reluctant to wear a visible headband-style device in public. For younger children, it is possible that the sensation of wearing a headband-style device may affect their willingness to use it. However, patients would be able to wear such devices in the car or in the comfort of their home during symptom-provoking activities without social pressure. Additionally, it is possible that the nVSM device may not need to be worn continuously, but rather only during heightened episodes of symptom aggravation. This flexibility may improve compliance. Future studies will evaluate longer treatment durations and home use protocols to better emulate real-world conditions.

Despite these limitations, these results suggest that the nVSM device may offer an alternative for symptom management for pediatric patients who have limited response to traditional treatments. Its ease of use, minimal risk, and immediate perceived benefit point to potential clinical relevance, especially for children who may not tolerate or benefit from medications or rehabilitation. ⁵ The nVSM device may be promising in reducing symptoms relating to vestibular dysfunction and could provide another option for children who have exhausted other treatments.

Conclusion

In this uncontrolled pilot study, patients reported symptom reductions while using the device. While our preliminary findings suggest potential benefit, clinical adoption of nVSM technology for pediatric vertigo would require validation through randomized, blinded, controlled trials with adequate statistical power. For the patients enrolled in this study, all have previously attempted to manage their vestibular dysfunction through migraine medications and vestibular rehabilitation therapy. Noninvasive options are worth exploring, as the device offers symptom relief without the side effects of medication or the time commitment of vestibular rehabilitation. It provides a low-risk intervention that can be used at home or during travel, potentially increasing accessibility.