Vibratory Stimuli Research Articles

Static and dynamic proprioceptive recognition through vibrotactile stimulation

Objective. Proprioceptive information provides individuals with a sense of our limb’s static position and dynamic movement. Impaired or a lack of such feedback can diminish our ability to perform dexterous motions with our biological limbs or assistive devices. Here we seek to determine whether both static and dynamic components of proprioception can be recognized using variation of the spatial and temporal components of vibrotactile feedback. Approach. An array of five vibrotactors was placed on the forearm of each subject. Each tactor was encoded to represent one of the five forearm postures. Vibratory stimulus was elicited to convey the static position and movement of the forearm. Four experimental blocks were performed to test each subject’s recognition of a forearm’s simulated static position, rotational amplitude, rotational amplitude and direction, and rotational speed. Main results. Our results showed that the subjects were able to perform proprioceptive recognition based on the delivered vibrotactile information. Specifically, rotational amplitude recognition resulted in the highest level of accuracy (99.0%), while the recognition accuracy of the static position and the rotational amplitude-direction was the lowest (91.7% and 90.8%, respectively). Nevertheless, all proprioceptive properties were perceived with >90% accuracy, indicating that the implemented vibrotactile encoding scheme could effectively provide proprioceptive information to the users. Significance. The outcomes suggest that information pertaining to static and dynamic aspects of proprioception can be accurately delivered using an array of vibrotactors. This feedback approach could be used to potentially evaluate the sensorimotor integration processes during human–machine interactions, and to improve sensory feedback in clinical populations with somatosensory impairments.

Perspectives of using vibrational communication data to develop safe methods for insect population size control

The transition to organic farming requires the development of new methods of population pest control without using insecticides. Accumulating evidence of insect vibrational communication indicate that the use of natural and modified signals pests may impede their successful communication on the plant, thereby reducing their population. Therefore, this study was conducted during 20 August to 16 October 2020 at Kharkevich Institute and discusses the effectiveness of using impetuses on the example widespread species Pentatoma rufipes which can damage large range of plants. Artificial models of stimuli, which were based on calling songs and rival signals of P. rufipes changed the behavior of female insects authentically in compared with control variant. The differences between duration of latent periods and number of successful approaches to the source of stimuli were discovered. There were shown, that artificial stimuli were attractive for females, wherein the difference of preferences between calling song and rival signals were more likely qualitative, i.e., stimuli were attractive equally. This fact explains by the way that agonistic behavior of males was directed only on the representatives of the same gender, not on females. We suppose that these signals can be used to increase efficiency of traditional methods of pest control, for example for attract insects to glue or pheromone traps. Both calling song (N = 16) and rival (N = 15) signals were used as stimuli. Two main behavioral responses of females to the stimulus were assessed - the latency period from the beginning of the stimulus application to the start of active movement of the female, % of successful approaches to the stimulus source. Control - no stimulus (N=15). The latency periods with and without stimulation differed significantly. The percentage of positive responses to stimuli was significantly higher than in the control (U-Mann-Whitney test; * p <0.05). On the contrary, the latency period before the onset of activity in the absence of a stimulus was significantly longer (Mann-Whitney U-test; p <0.05). No significant differences were found in the number of approaches to the stimulus between calling songs and rival signals. However, there is a noticeable tendency to an increase in the number of approaches when playing the calling song (62 and 48%, respectively). Differences in the latent periods of the activity of females in control and during stimulation show that the vibrational signals of males have a communication value. In future, the authors plan to show that when used together, vibration stimuli will increase the effectiveness of traditional glue and pheromone traps for P. rufipes.

Editorial

Welcome to the sixth issue in 2021. I am very pleased to announce the journals’ Scopus CiteScore of 2.0 for 2020 indicating another scientifically successful year. On behalf of the J.UCS team, I would like to thank all authors for their sound research contributions, the reviewers for their very helpful suggestions and the consortium members for their financial support. Your commitment and dedicated work have strongly contributed to the long-lasting success of our journal. In this regular issue, I am very pleased to introduce five accepted papers from six different countries and 17 involved authors. Edinelço Dalcumune, Luis Antonio Brasil Kowada, André da Cunha Ribeiro, Celina Miraglia Herrera de Figueiredo and Franklin de Lima Marquezino from Brazil present in their article a new algorithm for synthesis of reversible circuits for arbitrary n-bit bijective functions using generalized Toffoli gates, which include positive and negative controls. Murat Firat, Derya Yiltas-Kaplan and Ruya Samli introduce their work on a machine learning method - including Artificial Neural Network (ANN), Linear Regression (LR) and Gradient Boosting (GB) - for determining optimal seat capacity that can supply the highest load factor for the flight operation between any two countries. In a collaborative research between Switzerland, China and the Netherlands Fabian Honegger, Yuan Feng and Matthias Rauterberg have investigated in their research effects of visual, auditory, vibration and draught stimuli on the sense of presence. Julio Moreno, David G. Rosado, Luis E. Sánchez, Manuel A. Serrano and Eduardo Fernández-Medina from Spain discuss in their research a security reference architecture for cyber-physical systems. Adem Tuncer from Turkey introduces a new approach based on a Artificial Bee Colony Algorithm for solving the 15-puzzle problem.

Evaluating the effect of multi-sensory stimulations on simulator sickness and sense of presence during HMD-mediated VR experience

Some lines of evidence have shown that sensory input, especially related to vestibular and somatosensory stimulation, may reduce the symptoms related to simulator sickness and increase the sense of presence in VR. The present study aims at understanding how mechanical vibration and auditory stimulation can be used to improve user experience in the context of VR mediated by head-mounted displays. Four different groups comprising a total of 80 participants were tested under different conditions of sensory input (visual and vibration, visual-auditory, combined visual-auditory and vibratory, and visual only), during a VR roller-coaster experience. No significant differences in simulator sickness were found between the groups exposed to seat vibration and/or audio. However, sense of presence showed to be increased when vibratory stimuli were included. Post-hoc analyses showed that female users but not male ones, experienced an increase of sense of presence when vibratory stimulation was used. Practitioner summary: The study showed that including sound or vibration stimulation during VR experience does not reduce simulator sickness. However, sense of presence is promoted by vibratory stimulation. Post-hoc analyses showed that female users experienced an increase of sense of presence by vibratory stimulation, but not male ones.

Free and Forced Vibration Modes of the Human Fingertip

Computational analysis of free and forced vibration responses provides crucial information on the dynamic characteristics of deformable bodies. Although such numerical techniques are prevalently used in many disciplines, they have been underutilized in the quest to understand the form and function of human fingers. We addressed this opportunity by building DigiTip, a detailed three-dimensional finite element model of a representative human fingertip that is based on prior anatomical and biomechanical studies. Using the developed model, we first performed modal analyses to determine the free vibration modes with associated frequencies up to about 250 Hz, the frequency at which humans are most sensitive to vibratory stimuli on the fingertip. The modal analysis results reveal that this typical human fingertip exhibits seven characteristic vibration patterns in the considered frequency range. Subsequently, we applied distributed harmonic forces at the fingerprint centroid in three principal directions to predict forced vibration responses through frequency-response analyses; these simulations demonstrate that certain vibration modes are excited significantly more efficiently than the others under the investigated conditions. The results illuminate the dynamic behavior of the human fingertip in haptic interactions involving oscillating stimuli, such as textures and vibratory alerts, and they show how the modal information can predict the forced vibration responses of the soft tissue.

Dose-Response Effect of Vibratory Stimulus on Synaptic and Muscle Plasticity in a Middle-Aged Murine Model.

Whole body vibration plays a central role in many work categories and can represent a health risk to the musculoskeletal system and peripheral nervous system. However, studies in animal and human models have shown that vibratory training, experimentally and/or therapeutically induced, can exert beneficial effects on the whole body, as well as improve brain functioning and reduce cognitive decline related to the aging process. Since the effects of vibratory training depend on several factors, such as vibration frequency and vibration exposure time, in this work, we investigated whether the application of three different vibratory protocols could modulate synaptic and muscle plasticity in a middle-aged murine model, counteracting the onset of early symptoms linked to the aging process. To this end, we performed in vitro electrophysiological recordings of the field potential in the CA1 region of mouse hippocampal slices, as well as histomorphometric and ultrastructural analysis of muscle tissue by optic and transmission electron microscopy, respectively. Our results showed that protocols characterized by a low vibration frequency and/or a longer recovery time exert positive effects at both hippocampal and muscular level, and that these effects improve significantly by varying both parameters, with an action comparable with a dose–response effect. Thus, we suggested that vibratory training may be an effective strategy to counteract cognitive impairment, which is already present in the early stages of the aging process, and the onset of sarcopenia, which is closely related to a sedentary lifestyle. Future studies are needed to understand the underlying molecular mechanisms and to determine an optimal vibratory training protocol.

Effects of Sinusoidal Vibrations on the Motion Response of Honeybees

Vibratory signals play a major role in the organization of honeybee colonies. Due to the seemingly chaotic nature of the mechano-acoustic landscape within the hive, it is difficult to understand the exact meaning of specific substrate-borne signals. Artificially generated vibrational substrate stimuli not only allow precise frequency and amplitude control for studying the effects of specific stimuli, but could also provide an interface for human-animal interaction for bee-keeping-relevant colony interventions. We present a simple method for analyzing motion activity of honeybees and show that specifically generated vibrational signals can be used to alter honeybee behavior. Certain frequency-amplitude combinations can induce a significant decrease and other signals might trigger an increase in honeybees’ motion activity. Our results demonstrate how different subtle local modulatory signals on the comb can influence individual bees in the local vicinity of the emitter. Our findings could fundamentally impact our general understanding of a major communication pathway in honeybee colonies. This pathway is based on mechanic signal emission and mechanic proprio-reception of honeybees in the bee colony. It is a candidate to be a technologically accessible gateway into the self-regulated system of the colony and thus may offer a novel information transmission interface between humans and honeybees for the next generation of “smart beehives” in future beekeeping.

Oxidation processes at the surface of BaTiO3 thin films under environmental conditions

Dissociation and adsorption of water on ferroelectric oxide surfaces playimportant role in the processes of screening and switching dynamics of ferroelectric polarization, as well as in catalytic processes which can be additionally coupled with light, temperature or vibration stimuli. In this work,we present XPS study of ferroelectric BaTiO3thin films and determine the entanglement between surface chemistry, polarization direction and stability, by observing changes upon time exposure to environmental conditions, heating in O2atmosphereandirradiation in vacuum. We devote special attention to Ba 3d spectral region and identify two different oxidation states of O atoms in the compounds of Ba. While this second specie was generally attributed to Ba in surface compounds where it has different oxygen coordination than in the bulk, based on the XPS results of oxygen annealed thin films,we demonstrate that this so far neglected component, corresponds to barium peroxide (BaO2)and identify it as important active specie for the study of screening mechanisms closely related with catalytic activity present in this ferroelectric material. Finally, we report on chemically assisted polarization switching in thin films induced byheating in vacuum or exposure to X-Ray radiation due to the formation of positive surface electric field created by oxygen orelectron vacancies, respectively.

Effect of contingent vibratory stimulus via an oral appliance on sleep bruxism after the splint adaptation period

Contingent vibratory feedback stimuli applied by a specially designed oral appliance (OA) have been reported to be effective in reducing sleep bruxism (SB). However, the inhibitory effects of the OA, which occur immediately after OA delivery, may have confounded this finding. This study sought to shed light on the effects of vibratory stimuli on SB after the OA adaptation period, when its inhibitory effects are diminished. Fourteen 'definite' SB patients were enrolled. A force-based bruxism detection system was utilised to trigger a vibrator attached to the OA. Masseter electromyographic activity during sleep was recorded at home using portable polysomnography. After using the OA without vibratory stimulus for 16 nights (adaptation period), intermittent vibratory stimuli were applied every other half-hour for four nights (intervention period). Electromyographic activity over 10% of the maximum voluntary contraction was regarded as a SB episode. The number and the total duration of SB episodes per hour of sleep were calculated for the sessions with and without stimuli separately and averaged for four intervention nights. The effects of stimuli on these two variables were evaluated. The number and the total duration of the sessions without stimuli were 5.2episodes/h and 35.3s/h, respectively. These values significantly decreased to 3.9episodes/h and 15.1s/h (p<.05) for the sessions with vibratory stimuli. Contingent vibratory stimulus via an OA may be effective for the management of SB even after adaptation to OA.

Summating potentials from the utricular macula of anaesthetized guinea pigs

The Summating Potential (SP) was first recorded in the cochlea in the 1950s and represents an objective measure of cochlear hair cell function, in vivo. Despite being a regular tool in hearing research, a similar response has not yet been recorded from the vestibular system. This is mainly due to the lack of experimental techniques available to record electrical vestibular hair cell responses in isolation from the much larger cochlear potentials. Here we demonstrate the first recordings of the vestibular SP, evoked by Bone-Conducted Vibration (BCV) and Air-Conducted Sound (ACS) stimuli, in anaesthetized guinea pigs. Field potential measurements were taken from the basal surface of the utricular macula, and from the facial nerve canal following surgical or chemical ablation of the cochlea. SPs were evoked by stimuli with frequencies above ~200 Hz, and only with moderate to high intensity (~0.005–0.05 g) BCV and ACS (~120–140 dB SPL). Neural blockade abolished the Vestibular short-latency Evoked Potential (VsEP) and Vestibular Nerve Neurophonic (VNN) from the facial nerve canal recordings but did not abolish the vestibular SP nor the vestibular microphonic. Importantly, the vestibular SP was irreversibly abolished from the utricle and facial nerve canal recordings following local gentamicin application, highlighting its hair cell origin. This is the first study to record the Summating Potential from the mammalian vestibular system, in vivo, providing a novel research tool to assess vestibular hair cell function during experimental manipulations and animal models of disease.

Effectiveness of whole-body vibration or biofeedback postural training as an add-on to vestibular exercises rehabilitation therapy in chronic unilateral vestibular weakness: A randomized controlled study.

The efforts to achieve better functional results in vestibular rehabilitation have been continued by using different visual and somatosensory stimuli for a long time. Whole-body vibration (WBV) is a mechanical vertical stimulation that provides high frequency vibration stimulus to the proprioceptive receptors. Biofeedback provides continuous information to the subject regarding postural changes. These techniques may aid to improve vestibular rehabilitation. We aimed to investigate the effect of adding WBV or biofeedback postural training (BPT) to standard rehabilitation exercises in patients with chronic unilateral vestibular weakness. Ninety patients were randomized into three groups. Group 1 had WBV and Group 2 BPT in addition to the standard rehabilitation exercises. Group 3 only carried out the home-based exercises and served as the control. Outcome measures such as static posturography, Berg Balance Scale, Timed Up-and-Go test, Visual Analog Scale, and Dizziness Handicap Inventory (DHI) were used for comparison. Statistically significant gains were achieved in all groups with all parameters at the end of treatment when compared to baseline (p < 0.05). The patients in Group 1 (WBV), however, were significantly better than those in Groups 2 and 3 at the static posturographic stability score, Berg Balance Scale, and DHI (p < 0.05). Adding WBV to a rehabilitation program may be an effective strategy to improve postural stability and achieve better physical, functional and emotional outcomes.

Perception of Static Position and Kinesthesia of the Finger using Vibratory Stimulation.

Proprioception provides information regarding the state of an individual's limb in terms of static position and kinesthesia (dynamic movement). When such feedback is lost or impaired, the performance of dexterous control of our biological limbs or assistive devices tends to deteriorate. In this study, we determined if external vibratory stimulation patterns could allow for the perception of a finger's static position and kinesthesia. Using four tactors and two stimulus levels, eight vibratory settings corresponded to eight discrete finger positions. The transition patterns between these eight settings corresponded to kinesthesia. Three experimental blocks assessed the perception of a finger's static position, speed, and movement (amplitude and direction). Our results demonstrated that both position and kinesthesia could be recognized with over 93% accuracy. The outcomes suggest that vibratory stimulus can inform subjects of static and dynamic aspects of finger proprioception. This sensory stimulation approach can be implemented to improve outcomes in clinical populations with sensory deficits, and to enhance user experience when users interact with assistive devices.

270 Sleep Enhancement Technology: A Survey of Devices

Abstract Introduction Innovations in consumer sleep technologies have risen exponentially and providers struggle to keep up with patient expectations in this arena. Although there is high quality data on the validity on commercial sleep monitoring devices, there has been a rise in devices for the explicit purpose of sleep enhancement. We sought to identify existing consumer sleep devices that claim to enhance sleep, provide a comprehensive review of the main characteristics of these devices, and look into the types of evidence the developers offered to support their claims. Methods Using a scoping review framework we identified and mapped out the main characteristics of sleep enhancement devices in the consumer market. We systematically used a common search engine and the FDA database using various combinations of sleep-related search terms, such as “sleep enhancement device”. Through an iterative process, we identified and categorized devices based on the intervention target. Devices that were exclusively for clinical use and required a prescription, such as for the treatment of obstructive sleep apnea or diagnosed insomnia, were excluded. Results We identified 34 sleep enhancement devices, all 34 were found via web search and one was also found in the FDA Database. We defined the following overlapping categories: reduce sleep latency (94.1%), increase restorative sleep (17.6%), and/or “other” (32.4%). About half of the devices use sound (44.1%), 26.5% use visual stimuli, and 11.8% use vibration. Additionally, roughly a third of all devices claim to entrain brain signals associated with sleep. Half of devices found operate near the bed without being in contact with the consumer, 44.1% are worn on the body, and the remaining 5.9% operate in bed, near the consumer. Conclusion For the most part, commercial sleep enhancement devices target sleep latency or claim to increase the restorative power of sleep. These devices generally use auditory, visual, and vibratory stimuli, and half are worn on the body. Lack of evidence supporting whether these devices actually improve sleep questions the utility of such devices and demonstrates the need for validation standards for consumer sleep enhancement devices. Support (if any) Department of Defense Military Operational Medicine Research Program (MOMRP)

Schooling in Xenopus laevis Tadpoles as a Way to Assess Their Neural Development.

Escape behaviors, orienting reflexes, and social behaviors in Xenopus laevis tadpoles have been well-documented in the literature. Schooling behavior experiments allow for the observation of tadpole social interactions and in the past have been used to characterize behavioral deficits in models of neurodevelopmental disorders. Unlike other species of frogs, Xenopus tadpoles show polarized schooling. Not only do tadpoles aggregate, they also swim in the same direction. Quantifying both aggregation and relative swim angle can give us an important measure of social behavior and sensory integration. Past iterations of these experiments have required the continued presence of an experimenter throughout the duration of each trial and relied on expensive software for subsequent data analysis. The instrument configuration and analysis protocol outlined here provide an automated method to assess schooling by delivering a series of timed vibratory stimuli to a group of tadpoles to induce swimming behavior and then controlling a camera to document their positions via still images. Both stimulus delivery and image acquisition are automated using the Python programming language. Analysis is done using ImageJ and custom Python scripts, which are provided in this protocol. The specific equipment configuration and scripts shown here provide one solution, but other equipment and custom scripts can be substituted.

Foot and ankle somatosensory deficits in children with cerebral palsy: A pilot study.

To investigate foot and ankle somatosensory function in children with cerebral palsy (CP). Ten children with spastic diplegia (age 15 ± 5 y; GMFCS I-III) and 11 typically developing (TD) peers (age 15 ± 10 y) participated in the study. Light touch pressure and two-point discrimination were assessed on the plantar side of the foot by using a monofilament kit and an aesthesiometer, respectively. The duration of vibration sensation at the first metatarsal head and medial malleolus was tested by a 128 Hz tuning fork. Joint position sense and kinesthesia in the ankle joint were also assessed. Children with CP demonstrated significantly higher light touch pressure and two-point discrimination thresholds compared to their TD peers. Individuals with CP perceived the vibration stimulus for a longer period compared to the TD participants. Finally, the CP group demonstrated significant impairments in joint position sense but not in kinesthesia of the ankle joints. These findings suggest that children with CP have foot and ankle tactile and proprioceptive deficits. Assessment of lower extremity somatosensory function should be included in clinical practice as it can guide clinicians in designing more effective treatment protocols to improve functional performance in CP.

Anthropogenic underwater vibrations are sensed and stressful for the shore crab Carcinus maenas

Acoustic pollution in aquatic environments has increased with adverse effects on many aquatic organisms. However, little work has been done considering the effects of the vibratory component of acoustic stimuli, which can be transmitted in the substrate and propagated into the aquatic medium. Benthic marine organisms, including many invertebrates, are capable of sensing seabed vibration, yet the responses they trigger on organism have received little attention. This study investigates the impact of underwater vibration on the physiology and behaviour of a ubiquitous inhabitant of coastal areas of the northern hemisphere, the shore crab Carcinus maenas. We developed a novel vibratory apparatus with geophones supported on a softly sprung frame to induce a seabed vibration of 20 Hz frequency, as observed during dredging, piling and other anthropogenic activities. The geophone internal mass caused the frame to vibrate in a controlled manner. Our results show that transition from ambient to anthropogenic vibrations induced an increase in activity and antennae beats in shore crabs, indicating perception of the vibratory stimulus and a higher stress level. There was also a trend on sex-specific responses to anthropogenic vibration, with males showing a higher activity level than females. However, no effect of anthropogenic vibrations was found upon oxygen consumption. These results show that anthropogenic underwater vibration induces behavioural responses in Carcinus maenas. This highlights the importance of evaluating man-made vibratory activities on coastal invertebrates and the necessity of evaluating anthropogenic effects on both sexes.

A P300 Brain-Computer Interface Paradigm Based on Electric and Vibration Simple Command Tactile Stimulation.

This paper proposed a novel tactile-stimuli P300 paradigm for Brain-Computer Interface (BCI), which potentially targeted at people with less learning ability or difficulty in maintaining attention. The new paradigm using only two types of stimuli was designed, and different targets were distinguished by frequency and spatial information. The classification algorithm was developed by introducing filters for frequency bands selection and conducting optimization with common spatial pattern (CSP) on the tactile evoked EEG signals. It features a combination of spatial and frequency information, with the spatial information distinguishing the sites of stimuli and frequency information identifying target stimuli and disturbances. We investigated both electrical stimuli and vibration stimuli, in which only one target site was stimulated in each block. The results demonstrated an average accuracy of 94.88% for electrical stimuli and 95.21% for vibration stimuli, respectively.

Analysis of the effect of a one-time vibrotherapy treatment on selected skin characteristics, body composition and body circumferences of women with lipodystrophy

Lipodystrophy is a common problem that is more common in women than in men. Among the many methods of therapy, local vibrotherapy can be distinguished. However, the literature does not indicate which parameters describing the vibration stimulus show the optimal effect. The aim of the study was to indicate the vibration parameters which, after a single treatment, will affect selected skin features, composition and body circumferences of women with lipodystrophy. A study was conducted among 33 women who were divided into two groups and underwent a one-time vibration treatment with the use of low and high vibration parameters. Changes in body parameters were noticed in all women. Vibration treatments used to eliminate cellulite must be performed in series. With a single treatment, the use of a less intense stimulus may bring more beneficial effects to the skin. Studies with an extended observation protocol will indicate in the future whether these beneficial effects are adaptable.

Alms1 mutant zebrafish do not show hair cell phenotypes seen in other cilia mutants.

Multiple cilia-associated genes have been shown to affect hair cells in zebrafish (Danio rerio), including the human deafness gene dcdc2, the radial spoke gene rsph9, and multiple intraflagellar transport (IFT) and transition zone genes. Recently a zebrafish alms1 mutant was generated. The ALMS1 gene is the gene mutated in the ciliopathy Alström Syndrome a disease that causes hearing loss among other symptoms. The hearing loss seen in Alström Syndrome may be due in part to hair cell defects as Alms1 mutant mice show stereocilia polarity defects and a loss of hair cells. Hair cell loss is also seen in postmortem analysis of Alström patients. The zebrafish alms1 mutant has metabolic defects similar to those seen in Alström syndrome and Alms1 mutant mice. We wished to investigate if it also had hair cell defects. We, however, failed to find any hair cell related phenotypes in alms1 mutant zebrafish. They had normal lateral line hair cell numbers as both larvae and adults and normal kinocilia formation. They also showed grossly normal swimming behavior, response to vibrational stimuli, and FM1-43 loading. Mutants also showed a normal degree of sensitivity to both short-term neomycin and long-term gentamicin treatment. These results indicate that cilia-associated genes differentially affect different hair cell types.

Reducing the foot trajectory variabilities during walking through vibratory stimulation of the plantar surface of the foot

Variabilities or fluctuations in foot clearance are considered as a risk factor for falls during walking in older adults. The present study aimed to investigate whether the foot trajectory variability can be reduced by applying vibratory stimulation to the foot's plantar surface during walking. Ten healthy adults were asked to walk on a treadmill with vibratory shoes, and body kinematics were measured. Changes in the mean absolute deviations of the foot trajectory and joint and trunk angles were compared between the periods of applied or absent vibratory stimulus. Our results demonstrated that toe trajectory variability in the swing phase was significantly smaller when a vibratory stimulus was applied. Applying vibratory stimulus to the soles of the forefoot could potentially be used to reduce foot trajectory variability, which could reduce the risk of trips and associated falls during walking in older adults.