Vibrotactile Stimulation Research Articles

A novel device for studying temperature and touch interactions.

Recently, there has been increasing interest in developing auditory-to-vibrotactile sensory devices. However, the potential of these technologies is constrained by our limited understanding of which features of complex sounds can be perceived through vibrations. The present study aimed to investigate the vibrotactile perception of acoustic features related to timbre, an essential component to identify environmental, speech and musical sounds. Discrimination thresholds were measured for six features: three spectral (number of harmonics, harmonic roll-off ratio, even-harmonic attenuation) and three temporal (attack time, amplitude modulation depth and amplitude modulation frequency) using auditory, vibrotactile and combined auditory + vibrotactile stimulation in 31 adult humans with normal tactile and auditory sensitivity. Result revealed that all spectral and temporal features can be reliably discriminated via vibrotactile stimulation only. However, for spectral features, vibrotactile thresholds were significantly higher (i.e., worse) than auditory thresholds whereas, for temporal features, only vibrotactile amplitude modulation frequency was significantly higher. With simultaneous auditory and tactile presentation, thresholds significantly improved for attack time and amplitude modulation depth, but not for any of the spectral acoustic features. These results suggest that vibrotactile temporal cues have a more straightforward potential for assisting auditory perception, while vibrotactile spectral cues may require specialized signal processing schemes.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-21908-4.

Objectives: Sports-related concussion (SRC) is mostly associated with contact and combat sports. However, emerging evidence suggest that cyclists are also at risk of repeated concussion injury. Moreover, long-term neurophysiological outcomes in cycling cohorts remain underexplored. This novel study investigated the long-term effect of repetitive concussions in cyclists. Road, mountain biking (MTB), and BMX riders with a history of concussions and self-reported persistent symptoms were assess for neurophysiology and cognitive–motor performance compared to previously concussed cyclists with no ongoing symptoms. Both groups were compared to age-matched with controls. Methods: Using a cross-sectional between-group design, 25 cyclists with a history of concussions (15 symptomatic, 10 asymptomatic) and 20 controls completed symptom reporting, cognitive and balance assessments (SCAT5), sensorimotor testing using vibrotactile stimulation, and neurophysiological assessments via transcranial magnetic stimulation (TMS). Results: Symptomatic cyclists reported a higher number of concussions compared to asymptomatic cyclists (p = 0.041). Cognitive testing revealed large effects (d > 1.0), with impaired concentration in symptomatic cyclists compared to controls (p = 0.005). Motor assessments demonstrated large effects (d > 1.0), with slower tandem gait times (p < 0.001) and greater errors (p = 0.02) in the symptomatic group. Sensorimotor testing indicated slowed simple reaction times (p = 0.001) and poorer temporal order judgement (p = 0.038). TMS showed large effects (d > 1.0) in increased cortical inhibition in the symptomatic group, with prolong cortical silent periods (p < 0.05) and large effects (d > 1.0), and reduced short interval intracortical inhibition (p = 0.001) compared to asymptomatic cyclists and controls. Conclusions: Cyclists reporting persistent symptoms showed greater cortical inhibition and impaired cognitive–motor performance, consistent with findings in contact sport athletes. These results suggest that repeated concussions in cycling carry risk of chronic neurophysiological alterations. Cycling disciplines should consider more rigorous concussion identification protocols and stricter management strategies to mitigate persistent and long-term consequences.

A literature review on vibrotactile stimulation devices for individuals with Parkinson's disease.

Neural oscillations in beta (13-30Hz) and gamma (>30Hz) frequency bands index a variety of sensorimotor and cognitive processes. To compare two rehabilitation regimens for chronic stroke patients with a hemiparetic hand, we randomly assigned them to either music-supported therapy or physiotherapy for 10 weeks. Previously, we reported the music group's improved motor speed, mood, well-being, and rhythm perception. Here, we investigated changes in neural oscillatory activities. Here, our magnetoencephalography (MEG) data showed significant group-by-session interaction in both somatosensory and auditory-motor paradigms. The control group exhibited a prominent increase in gamma-band frequencies accompanying the somatosensory steady-state responses entrained by 22-Hz vibrotactile stimulation, indicating compensatory functions from the contralesional brain. In contrast, the music group showed a gradual enhancement of auditory-motor coupling in beta-band event-related power changes during passive metronome listening. The music group's increase in beta dynamics in the auditory cortex aligns with our previous work and their improvement in behavioral rhythm perception. Whole-brain data during listening and tapping demonstrated reduced beta modulation in the sensorimotor and prefrontal cortices and temporal poles in the music group, likely related to movements with less effort and attention. The current findings contribute to understanding the frequency-specific communications of the auditory, sensory, and motor systems.

Vibrotactile stimulation has applications in a variety of fields, including medicine, virtual reality, and human–computer interaction. Eccentric Rotating Mass (ERM) vibrating motors are widely used in wearable haptic devices owing to their small size, low cost, and low-energy features. User experience with vibrotactile stimulation is an important factor in ergonomic design for these applications. The effects of ERM motor vibrations on upper-extremity sensation and perception, which are important in the design of better wearable haptic devices, have not been thoroughly studied previously. Our study focuses on the relationship between user sensation and perception and on different vibration parameters, including frequency, location, and number of motors. We conducted experiments with vibrotactile stimulation on 15 healthy participants while the subjects were both at rest and in motion to capture different use cases of haptic devices. Eight motors were placed on a consistent set of muscles in the subjects’ upper extremities, and one motor was placed on their index fingers. We found a significant correlation between voltage and sensation intensity (r = 0.39). This finding is important in the design and safety of customized haptic devices. However, we did not find a significant aggregate-level correlation with the perceived pleasantness of the simulation. The sensation intensity varied based on the location of the vibration on the upper extremities (with the lowest intensities on the triceps brachii and brachialis) and slightly decreased (5.9 ± 2.9%) when the participants performed reaching movements. When a single motor was vibrating, the participants’ accuracy in identifying the motor without visual feedback increased as the voltage increased, reaching up to 81.4 ± 14.2%. When we stimulated three muscles simultaneously, we found that most participants were able to identify only two out of three vibrating motors (41.7 ± 32.3%). Our findings can help identify stimulation parameters for the ergonomic design of haptic devices.

When designing a haptic interface, simplicity is crucial to avoid negative effects caused by excessive weight and complexity. Using multimodal information, haptic illusions, and providing context are known to create simpler interfaces. We have previously proposed the use of single overlapped vibrotactile stimulation (SOVS) for presenting spatiotemporal tactile perception, a method that simultaneously presents overlapped waveforms to multiple body parts. There, the acceleration measured from a person dribbling a basketball with an accelerometer positioned on the index finger and the floor was overlapped to present as stimuli. When the stimuli were presented simultaneously to the hand and the feet, it demonstrated a dribbling sensation, like an imaginary ball moving back and forth between the hand and the feet. This demonstrated the potential to eliminate the need for time synchronization and reduce the number of required channels, ultimately leading to the development of simple haptic interfaces that enhance an immersive experience. In this paper, we aim to investigate the key factor behind the perception of SOVS using simple vibrotactile stimuli. The first experiment measured the occurrence rate of the dribbling feeling for different combinations of prepared stimuli, and the results show that the combination of two different input amplitudes is crucial for the occurrence rate of the phenomenon. The second experiment assessed how realistic each stimulus, presented to the hand and the feet separately, felt to the participants. The results show that for the hand, the perceived reality corresponded to the strength of input amplitude, whereas the second-strongest input amplitude was perceived as most realistic for the feet. This suggests that when the combination consists of duplicate input amplitudes and/or those with low perceived reality, the occurrence rate tends to decrease.

BackgroundThe neural mechanisms underlying somatosensory processing in individuals with acquired single-sided deafness (SSD) and potential central neuronal cross-modal reorganization remain largely unexplored. This study investigates the impact of SSD on somatosensory perception and attentional processing.MethodsElectrophysiological responses using EEG, and behavioral measures (discrimination thresholds, hit rates and reaction times) were assessed in adults with acquired SSD and normal-hearing (NH) controls for vibrotactile stimulation at two distinct frequencies. Differences in cortical somatosensory evoked potentials between adults with acquired SSD and normal-hearing (NH) controls, focusing on peak amplitudes and peak times of key event-related potential components (P50, N70, P100, N140, and P3b) and their cortical generators were assessed.ResultsWhile both groups exhibited comparable behavioral performance, significant differences emerged in electrophysiological responses. Individuals with SSD showed increased P3b amplitude (albeit non-significant) and significantly delayed P3b peak times, indicating that individuals with acquired SSD exhibit alterations in attentional mechanisms associated with somatosensory perception. In addition, source localization analysis of the P50 component using standardized low-resolution brain electromagnetic tomography (sLORETA) revealed group differences in cortical activation patterns, with SSD individual showing additional recruitment of auditory-related areas, including the superior temporal gyrus, the middle temporal gyrus and the insula. This further supports the notion of compensatory neuroplasticity in auditory pathways following severe to profound unilateral hearing loss.ConclusionOur results indicate that SSD is associated with neural reorganization in somatosensory and auditory pathways. The observed modifications in both early and late somatosensory responses, coupled with alterations in source activity, suggest that individuals with SSD engage alternative neural mechanisms when processing vibrotactile stimuli, differing from the typical patterns observed in NH individuals. Understanding these changes prior to cochlear implantation will facilitate the development of personalized auditory rehabilitation strategies following cochlear implantation.

ABSTRACTTouch has an affective dimension, conveyed through low‐threshold mechanoreceptors known as C‐tactile (CT) afferents, which are activated by gentle, caress‐like contact. While there is evidence that these fibers modulate nociceptive input, their influence on the processing of other somatosensory afferent activity remains largely unknown. In this study, we explored how slow brushing (CT‐optimal stimulation) modulates somatosensory evoked potentials (SEPs) elicited by electrical stimulation of the median nerve (occurring at 0.7 to 3.7 s after stimulus onset), compared to vibration (at 200 Hz) and no touch, in 30 healthy participants. CT‐targeted stimulation was delivered using a robotic arm developed in‐house equipped with a cosmetic brush, which applied slow brushing movements at CT‐optimal speeds (~3 cm/s) over the dorsal forearm. Vibrotactile stimulation, targeting A‐beta fibers, was delivered using vibration motors adjacent to the brushed area, with intensity calibrated to match the perceived strength of brushing. SEPs were recorded under these three conditions. Our results showed no differences between slow brushing, vibration, and no touch conditions in the amplitude of early SEPs recorded over the somatosensory cortex (N20, P25, N30, and P45), which may indicate that CT stimulation does not affect early cortical processing of somatosensory information. However, a reduced frontocentral P150 SEP component was observed during slow brushing compared to the other conditions. This finding suggests that CT stimulation may reduce somatosensory input transmitted through the lemniscal system, possibly engaging brain areas involved in attentional and cognitive processing.

Usability and Feasibility of In-home Vibro-Tactile Stimulation for Treating Voice Symptoms in Laryngeal Dystonia.

Background: Alzheimer’s disease is a progressive neurodegenerative disorder characterized by cognitive decline and memory loss. Gamma (γ) oscillations are closely linked to learning and memory, and recent interest has grown around Gamma ENtrainment Using Sensory stimulation (GENUS) as a non-invasive neuromodulation strategy. However, the therapeutic impact of vibrotactile gamma stimulation under varying physical parameters such as acceleration remains underexplored. Methods: Differentiated SH-SY5Y cells were treated with amyloid-β (Aβ) and exposed to vibrotactile stimulation at 2.2 or 4.0 m/s2. In vivo, male C57BL/6N mice (7 weeks old, 35 g) were administered scopolamine to induce neurotoxicity and randomly assigned to sham, scopolamine, donepezil, or vibrotactile stimulation groups (n = 10 each). Behavioral tests, biochemical assays, Western blotting, and immunohistochemistry were performed to evaluate cognitive function, oxidative stress, cholinergic activity, synaptic plasticity, and neuroinflammation. Results: In vitro, SH-SY5Y cells exposed to amyloid-beta (Aβ) were treated with vibrotactile stimulation, resulting in enhanced neuronal marker expression at 2.2 m/s2. In vivo, mice receiving stimulation at 2.2 m/s2 showed improved cognitive performance, reduced oxidative stress, restored cholinergic function, suppressed neuroinflammation, and enhanced synaptic plasticity. Mechanistically, these effects were associated with activation of the AKT/GSK3β/β-catenin pathway. Conclusions: Our findings demonstrate that vibrotactile gamma stimulation at 2.2 m/s2 exerts greater therapeutic efficacy than higher acceleration, highlighting the importance of optimizing stimulation parameters. This work supports the potential of acceleration-tuned, non-invasive GENUS-based therapies as effective strategies for cognitive recovery in neurodegenerative conditions.

While scientific research has extensively explored how the brain integrates touch and pain signals, the cerebral processing of specific vibrotactile frequencies remains poorly understood. This gap is particularly significant given clinical evidence that vibrotactile stimulation can reduce pain in both chronic pain patients and experimental settings. Our study investigated the cortical electrophysiological correlates of peripheral vibrotactile stimulation across different frequencies in healthy volunteers, with a focus on frequency-dependent patterns of neuronal activation. While electroencephalogram (EEG) was recorded, healthy participants received vibrotactile stimulation (high-frequency burst stimulation with different inter-burst intervals) to the left index fingertip at frequencies corresponding to established neural rhythms: delta (2 Hz), theta (6 Hz), alpha (12 Hz), beta (20 Hz), and gamma (40 Hz). We compared the EEG bandwidth activity between vibrotactile stimulation conditions relative to resting baseline. Our findings demonstrated that vibrotactile stimulation produces distinct frequency-dependent patterns of cortical activation. A key finding was that 6 Hz stimulation selectively enhanced theta power in the left prefrontal cortex - an electrophysiological signature previously linked to successful pain relief. These findings advance the understanding of the “spectrotopic” nature of vibrotactile frequency processing in the cortex and provide a mechanistic foundation for developing novel vibration-based therapies in the future.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-14870-8.

Demonstrate proof-of-concept that superficial vibro-tactile stimulation (VTS) of the larynx can serve as a non-invasive neuromodulation method to reduce voice symptoms in people with abductor-type laryngeal dystonia (ABLD) and record the underlying neural response to VTS of the somatosensory-motor cortex. Using a wearable collar with embedded vibrators, 11 people with ABLD received VTS for 24 min. To assess voice effects, they vocalized vowels and spoke standardized test sentences and words. Cortical activity was recorded using 64-channel EEG. Smoothed cepstral peak prominence, cumulative word and sentence duration were derived from voice recordings as objective markers of speech quality next to perceived speech effort as a subjective marker. In response to VTS, 64% of participants rated their improvement in voice quality as noticeable to very noticeable. Analysis of objective voice measures indicated a reduction in voice symptoms in up to 45% of participants immediately after and/or 20 min past the cessation of VTS. The cortical response to VTS application was a reduced event-related spectral power in theta, alpha, and beta bands over left and right somatosensory-motor cortical areas that was most prominent over the left premotor cortex in 7/11 participants. Applying laryngeal VTS proved to be feasible and safe. VTS can induce acute short-term reductions in voice symptoms, which is important given the limited therapeutic options for ABLD. The electrocortical correlate of VTS was an event-related desynchronization of neuronal firing patterns over bilateral somatosensory-motor cortex.

Somatosensory cortical representations of the assimilation effect for vibrotactile stimulation.

Cortical activations induced by electrical versus vibrotactile finger stimulation using EEG.

Vibrotactile stimulation has been shown to enhance the music listening experience of cochlear implant (CI) users. However, while existing studies have focused on music perception, significant gaps remain in our understanding of how music induces emotions in CI users and the role of vibrotactile stimulation in this process. Furthermore, the after-effects of audio-vibrotactile music listening on audiometric test performances have not yet been investigated on CI users. This paper presents a study in which two groups of twelve CI users were each exposed to music alone and to music with concurrent vibrotactile stimulation delivered via a vest enhanced with actuators. Standardized tonal and speech tests were conducted before and after both types of exposure (audio and audio-vibrotactile). In particular, speech audiometry was conducted in the quiet condition (with no masking sounds) for the first group and with the competing sounds for the second group. Results from both groups consistently showed that the exposure to tactile music significantly enhanced CI users’ ability to decode tonal and speech signals compared to the effect resulting from exposure to sounds alone. The majority of participants preferred listening to music with concurrent vibrations over an audio-only experience, as it led to higher levels of immersion and engagement. Consistent with findings from previous studies on individuals with normal hearing, an increase in arousal in CI users was observed in the audio-vibrotactile condition compared to the absence of vibrations, regardless of the type of emotion being conveyed. Nevertheless, participants emphasized the need for vibrotactile devices to incorporate personalization mechanisms, allowing them to dynamically adjust vibration intensity for different body parts. These findings may open the door to novel therapeutic approaches for CI users.

Vibration offers a potential alternative modality for transcutaneous auricular vagus nerve stimulation (taVNS). However, mechanisms of action are not well-defined. The goal of this pilot study was to evaluate the potential of vibrotactile stimulation of the outer ear as a method for activating central brain regions similarly to established vagal nerve stimulation methods. Seven patients with intractable epilepsy undergoing stereotactic electroencephalography (sEEG) monitoring participated in the study. Vibrotactile taVNS was administered across five vibration frequencies (2, 6, 12, 20, and 40 Hz) following a randomized stimulation pattern with 30 trials per frequency. Spectral coherence during stimulation was analyzed across theta (4-8 Hz), alpha (8-13 Hz), beta (13-30 Hz), and broadband gamma (70-170 Hz) frequency bands. At the group level, vibrotactile taVNS significantly increased coherence in theta (effect sizes 6 Hz: r = 0.311; 20 Hz: r = 0.316; 40 Hz: r = 0.264) and alpha bands (effect sizes 20 Hz: r = 0.455; 40 Hz: r = 0.402). Anatomically, multiple limbic brain regions exhibited increased coherence during taVNS compared to baseline. The percentage of total electrode pairs demonstrating increased coherence was also quantified at the individual level. Twenty Hz vibration resulted in the highest percentage of responder pairs across low-frequency coherence measures, with a group-average of 33% of electrode pairs responding, though inter-subject variability was present. Overall, vibrotactile taVNS induced significant low-frequency coherence increases involving several limbic system structures. Further, parametric characterization revealed the presence of inter-subject variability in terms of identifying the vibration frequency with the greatest coherence response. These findings encourage continued research into vibrotactile stimulation as an alternative modality for noninvasive vagus nerve stimulation.

Neonatal Opioid Withdrawal Syndrome (NOWS) continues to be a major public health burden. Our objective was to assess the efficacy of a stochastic vibro-tactile stimulation (SVS) mattress in reducing initiation of pharmacotherapy in neonates at risk for NOWS. A multicenter, prospective, non-blinded, randomized clinical trial of neonates born ≥ 35 weeks gestation. Neonates randomized to either SVS mattress or standard crib mattress The outcomes examined were initiation of pharmacotherapy, readiness for discharge, NOWS monitoring scores, cry quality and mattress acceptability surveys. Of 62 infants enrolled, 4 infants (10.0%) in the SVS group and 4 infants (18.2%) in the standard group were initiated on pharmacotherapy. Infants in SVS group demonstrated early readiness for discharge, with no differences between the two groups for NOWS scoring or cry quality. Overall, 60% of nurses and 80% of parents found the SVS mattress helped calm the neonate. Although the SVS mattress demonstrated a trend towards lower initiation of pharmacotherapy and earlier readiness for discharge, the results were not statistically significant due to fewer neonates being enrolled than expected. The mattress was highly acceptable to parents and nurses. Registered at ClinicalTrials.gov ID # NCT04834297; https://clinicaltrials.gov/study/NCT04834297 IMPACT: Improving on current non-pharmacologic interventions for the prevention and treatment of Neonatal Opioid Withdrawal Syndrome (NOWS) is critically important. Our study focused on assessing the efficacy of a stochastic vibro-tactile stimulation (SVS) mattress in reducing the use of pharmacotherapy in neonates at risk for NOWS within the first 5 days after birth. In neonates at risk for NOWS, the SVS mattress may reduce the need for pharmacotherapy and improve readiness for discharge while being acceptable to parents and nurses.

Estimation of Virtual Force Sensation in Vibrotactile Stimulation during Grasping Tasks Using Machine Learning on Electroencephalogram Data

The glymphatic clearing function has been proposed to be dependent on 40 Hz gamma oscillation, which is fundamental for the pathogenesis of neurodegenerative diseases. It is evident that multisensory and vibrotactile stimulation have been proven to enhance gamma oscillation and boost glymphatic clearance of amyloid load. These multisensory stimulations induce gamma frequency entrainment via thalamus. The cholinergic neurons in basal forebrain provide massive projections to the olfactory bulb, hippocampus, and neocortex. Degeneration of these neurons causes smell loss, memory impairment and recognition deficits during the early stage of Alzheimer’s disease. Cholinergic neuronal degeneration is among the earliest events during AD development. The Olfactory pathway provides a powerful sensation bypassing the thalamus, and the olfactory gamma oscillation is synchronized with hippocampus. The olfactory bulb, hippocampus, and neocortex are modulated by the cholinergic neurons in basal forebrain, which, based our preliminary data, have been shown to be responsive to both odorant and nociceptive stimulus. On the other hand, olfactory LFP oscillations have been proposed as the mechanism that facilitates synchronization of olfactory output and odor information processing. Our team and other labs have reported that neuronal discharge in olfactory bulbs can be increased or depressed by stimulation of horizontal diagonal band (HDB) of the basal forebrain either through electrical or optogenetic stimulation, but how do these stimulations affect the local field potential oscillation remain poorly understood. Here we used electrical stimulation on HDB and investigated the oscillation the olfactory bulb in awake and anesthetized the mice. We observed spontaneous LFP activity in both olfactory bulb and HDB consisting of theta (2 - 12 Hz), beta (15 - 36 Hz) and gamma (40 - 80 Hz) band oscillations. We found that electrical stimulation of HDB (300 mA, 100 Hz, 25 pulses) induced increased spiking activity (Zhan, et al 2014) but did not significantly affect low and high gamma oscillation in the olfactory bulb in both awake and anesthetized mice with urethane (i.e., 1.5 g/kg). We also presented Odorants (sharpie alcohol mixtures: n-propanol, n-butanol and diacetone alcohol) to a different group of mice, which induced increased spiking activity and brief increase of oscillations across all bands of frequencies in the horizontal diagonal band in anesthetized mice. In addition, we used tail pinching that induced increased spiking activity and enhanced oscillation in high (70-100 Hz) and low gamma (40-70 Hz) bands in the horizontal diagonal band in anesthetized mice, but the theta (1-10 Hz) and beta (12-35 Hz) oscillations were not affected significantly. Our experiments suggest that light nociceptive or odor stimulus can increase gamma oscillation in the basal forebrain, thus may contribute to odor representation and may be involved in glymphatic perfusion and neurodegeneration. Karen Toffler Charitable Trust, DC CFAR Pilot Grant and the HUCOM Bridge Fund to XZ 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.