Auditory Biofeedback Research Articles

Reconnecting Anisometropic Amblyopic Eyes to the Cortex: VEP-Based Auditory Biofeedback.

This study aimed to evaluate the effectiveness of a visual rehabilitation method for anisometropic amblyopia that uses visual evoked potential (VEP) parameters and sound biofeedback to increase objectiveness. an observational, case-controlled trial. Ophthalmology Clinic, Emergency County Hospital, Cluj-Napoca, Romania. Sixteen subjects with amblyopic anisometropia, aged 15-57, and sixteen controls, aged 24-33, were included. Subjects were divided into two groups. The control group, composed of normal-vision subjects, and the amblyopic group received 10 training sessions. The rehabilitation program lasted 10 min, took place twice a week, and ran over five consecutive weeks. During each session, the subjects were asked to fixate on a target on the computer screen and were instructed to keep the fixation and maintain the sound of the biofeedback at high frequency. The study assessed the main visual parameters at baseline, after 10 sessions, and 1, 3, 6, and 12 months after treatment. Performance was evaluated by measuring visual acuity, contrast sensitivity, and reading velocity (words/minute). In the experimental group, mean BCVA improved with two rows, which means an improvement in the LogMARLogMAR scale with an average of nine letters. These values tended to be maintained over time. Both groups showed better reading velocities after training, but this parameter has undergone large variability during follow-ups. Contrast sensitivity was also improved and stable. Visual rehabilitation with the Retimax Vision Trainer can improve visual performance in patients with amblyopia after the critical period, an improvement that is maintained in most cases for at least one year after treatment.

Assessment of the Acute Effects of Wearable Sensor Derived Auditory Biofeedback on Gross Lumbar Proprioception

Lower back disorders (LBDs) affect a large proportion of the population, and treatment for LBDs have been shifting toward individualized, patient-centered approaches. LBDs are typically associated with poor proprioception. Therefore, there has been a recent uptake in the utilization of wearable sensors that can administer biofeedback in various industrial, clinical, and performance-based settings to improve lumbar proprioception. The aim of this study was to investigate whether wearable sensor-derived acute auditory biofeedback can be used to improve measures of gross lumbar proprioception. To assess this, healthy participants completed an active target repositioning protocol, followed by a training period where lumbar-spine posture referenced auditory feedback was provided for select targets. Target re-matching abilities were captured before and after acute auditory biofeedback training to extract measures related to accuracy and precision across spine flexion targets (i.e., 20%, 40%, 60%, 80% maximum). Results suggest a heterogenous response to proprioceptive training whereby certain individuals and spine flexion targets experienced positive effects (i.e., improved accuracy and precision). Specifically, results suggest that mid-range flexion targets (i.e., 40-60% maximum flexion) benefited most from the acute auditory feedback training. Further, individuals with poorer repositioning abilities in the pre-training assessment showed the greatest improvements from the auditory feedback training.

Model-based cueing-as-needed for walking in Parkinson's disease: A randomized cross-over study

BackgroundCorrecting of the lack of regularity in steps is a key component of gait rehabilitation in Parkinson's disease. We proposed to introduce adaptive spatial auditory cueing (ASAC) based on verbal instruction “lengthen the step” automatically delivered when the stride length decreased below a predetermined threshold. ObjectivesThe present study compared the effect of usual rhythmic auditory cueing versus ASAC used during a walking training in Parkinson's disease. MethodsFifteen patients with Parkinson's disease performed both interventions in randomized order, one week apart: a 20-minute walking training with rhythmic auditory cueing, in form of a metronome adjusted on 110% of the patient's own cadence, or ASAC delivered when the stride length is less than 110% of the patient's own stride length. Assessment criteria were walking distance covered during the intervention, speed, step length, cadence, coefficients of variation of step length and step duration, and indexes of spatial and temporal asymmetry during a walking test before and just after the intervention. ResultsThe walking distance is higher with ASAC compared with rhythmic auditory cueing (rhythmic auditory cueing, 905 (203) m, mean (standard deviation); ASAC, 1043 (212) m; P=0.002). Between-intervention comparison showed some similar effects on walking after the intervention including free speed and step length increases (P<0.05). ConclusionThe distance covered during 20-minute walking with ASAC increases by 15% compared to the use of classical rhythmic auditory cueing, while the immediate therapeutic effects show similar spatial-temporal benefits on short-distance walking. Auditory biofeedback cueing promoting the increase in step length might improve gait relearning in Parkinson's disease.

Addressing Empty Space Myopia to Enable Deep Space Travel with Extended Reality Auditory Biofeedback

Addressing Empty Space Myopia to Enable Deep Space Travel with Extended Reality Auditory Biofeedback

Effects of biofeedback on biomechanical factors associated with chronic ankle instability: a systematic review with meta-analysis

BackgroundBiofeedback may alter the biomechanics of lower extremities in patients with chronic ankle instability (CAI). We aimed to systematically review the literature on the effect of gait-training and biofeedback on biomechanical parameters in individuals with CAI and conduct a meta-analysis.MethodsWe searched four databases including PubMed, Web of Science, Scopus and Embase from their inception through 30th June 2022. The Downs and Black appraisal scale was applied to assess quality of included studies. Two reviewers screened studies to identify those reporting the effect of biofeedback on biomechanical factors associated with CAI. Outcomes of interest were kinetics and kinematics. Two authors separately extracted data from included studies. Data of interest were study design, number of sessions, intervention, tools, outcomes, number, sex, age, height, and body mass of participants.ResultsThirteen studies with a total of 226 participants were included. Biofeedback was capable of shifting center of pressure (COP) and lateral plantar pressure medially and reducing foot inversion, adduction, propulsive vertical ground reaction force (vGRF), ankle joint contact force, peak pressure and pressure time integral in the lateral mid-foot and forefoot. Auditory biofeedback had agreater impact on modifying plantar pressure in individuals with CAI. The meta-analyses revealed that visual biofeedback reduces peak pressure in lateral mid-foot and pressure time integral at lateral and medial heel and pressure increases under the hallux.ConclusionBiofeedback can alter pressure, vGRF, and foot inversion associated with CAI. Auditory biofeedback had greater impact on modifying plantar pressure in individuals with CAI. Further studies are required to assess the prolonged effect and clinical consequences of biofeedback or a combination of feedback on CAI in different age groups. Moreover, developing a low-cost and user-friendly device that can be evaluated in high quality RCTs is important prior to implementing the intervention in the clinical setting to reduce symptoms of CAI.

Auditory feedback in tele-rehabilitation based on automated gait classification

In this paper, we describe a proof-of-concept for the implementation of a wearable auditory biofeedback system based on a sensor-instrumented insole. Such a system aims to assist everyday users with static and dynamic exercises for gait rehabilitation interventions by providing auditory feedback based on plantar pressure distribution and automated classification of functional gait disorders. As ground reaction force (GRF) data are frequently used in clinical practice to quantitatively describe human motion and have been successfully used for the classification of gait patterns into clinically relevant classes, a feed-forward neural network was implemented on the firmware of the insoles to estimate the GRFs using pressure and acceleration data. The estimated GRFs approximated well the GRF measurements obtained from force plates. To distinguish between physiological gait and gait disorders, we trained and evaluated a support vector machine with labeled data from a publicly accessible dataset. The automated gait classification was then sonified for auditory feedback. The potential of the implemented auditory feedback for preventive and supportive applications in physical therapy was finally assessed with both expert and non-expert participants. A focus group revealed experts’ expectations for the proposed system, while a usability study assessed the clarity of the auditory feedback to everyday users. The evaluation shows promising results regarding the usefulness of our system in this application area.

Design and Evaluation of a Wearable Biofeedback Training System to Reduce Trip-Related Falls During Level Walking

Trip-related falls are a major concern especially for older adults and individuals with gait impairments as they can lead to serious injuries, hospitalizations and negatively impact the quality of life. A low Minimum Toe Clearance (MTC) can be a predictor of tripping risk and thus, increasing the MTC is a possible way to reduce trip-related falls. In this paper, a wearable system is proposed that can measure the MTC in real-time using two Time-of-Flight (ToF) sensors on the shoe and provide auditory biofeedback using a piezo buzzer. Ten healthy female adults were recruited to walk in four conditions: baseline, biofeedback, short retention (same day), and long retention (next day) to design and validate our gait training tool. Average MTC values were compared pre-feedback, post-feedback, and post-retention, and our analysis revealed significant differences between the feedback and retention sessions for the training system. Therefore, the proposed system has the potential to be used as a wearable training system to minimize tripping risks in older adults and gait-impaired populations.

Within-session and between-session effects of auditory biofeedback training on center of pressure location during gait in patients with chronic ankle instability

ObjectivesTo establish preliminary gait training dosage parameters for patients with chronic ankle instability (CAI) by determining the within-session and between-session effects of auditory biofeedback training on center of pressure (COP) location during gait. DesignObservational Longitudinal. SettingLaboratory. Participants19 participants with CAI, 8 participants who did not receive auditory biofeedback (NoFeedback group) and 11 participants who did receive auditory biofeedback (AuditoryFeedback group) over an 8-session 2-week intervention. Main outcome measuresCOP location was measured at the start and at each 5-min interval during treadmill walking across all eight 30-min training sessions. ResultsThe AuditoryFeedback group had significant within-session lateral-to-medial shifts in COP location during only session-1 at the 15-min (45% of stance; peak mean difference = 4.6 mm), 20-min (35% and 45%; 4.2 mm), and 30-min time intervals (35% and 45%; 4.1 mm). Furthermore, the AuditoryFeedback group had significant between-session lateral-to-medial shifts in COP location at session-5 (35–55% of stance; 4.2 mm), session-7 (35%–95%; 6.7 mm), and session-8 (35%–95%; 7.7 mm). The NoFeedback group had no significant changes in COP location within-sessions or between-sessions. ConclusionsParticipants with CAI who received auditory biofeedback during gait needed an average of 15-min during session-1 to meaningfully shift their COP location medially and 4-sessions before retaining the adapted gait pattern.

The Effect of Modified Push-up Exercise Using Electromyography Biofeedback on Selection of Scapular Stabilizing Muscles

Background: The serratus anterior (SA) muscle is an important scapular stabilizer and has a profound role in retaining the scapulohumeral rhythm. Therefore, modified push-up plus (MPUP) has been advised to strengthen this muscle as a closed chain workout. However, few previous studies have reported the possibility of a reparative motion from pectoralis major (PM) that could replace and amend SA's function during push-up plus. Objectives: The current study examined MPUP's effect using biofeedback EMG on some of the selected scapular stabilizers. Methods: Sixteen healthy young subjects voluntarily participated in this study. Each subject performed push-ups, from the quadruped position, under two conditions (i.e., with or without visual and auditory biofeedback). Surface EMG measured pectoralis major, serratus anterior, and upper trapezius activity. A paired t-test was used to determine any statistically significant difference between the two conditions. Additionally, the effect size was calculated to quantify the magnitude of EMG biofeedback in each muscle. Results: MPUP training using biofeedback significantly increased SA muscle activity and decreased PM muscle activity, but there was no significant change in UT activity. Conclusions: Excessive PM activity was repressed because of biofeedback, and the workout was done with the enhancement of SA muscular activity. Thus, including biofeedback while doing MPUPs helps limit PM's supplementary action and enhance SA muscle activity.

Calming the Visual Storm: Management of Childhood Nystagmus

Childhood nystagmus creates a visual storm both for the affected child and the treating doctor. This problem occurring in the development phase of the child affects not only the vision but also the general development, if not diagnosed and managed in time. Moreover, some forms may even harbor a neurological tumor needing timely management. First, a brief introduction of nystagmus classification, a simplified approach to diagnose the common childhood nystagmus, and the value of electrophysiology will be presented. Next, the approach to treatment, using a thorough clinical examination, illustrated by patient examples of different types of nystagmus will be presented. The different forms of childhood nystagmus are described: idiopathic infantile nystagmus syndrome (IINS), sensory nystagmus (SN), fusion maldevelopment nystagmus (FMDN), spasmus nutans syndrome (SNS), nystagmus blockage syndrome, periodic alternating nystagmus, and others as well as their specific management. The role of electronystagmography and that of neuroimaging in specific conditions is life saving and is described. The role of auditory biofeedback, acupuncture, medical treatment, and surgical procedures like Augmented Anderson procedure, Hertle-Dell'Osso procedure, supra maximal retro-equatorial recession, and posterior fixation have been elucidated. Newer techniques have simplified the management options and improved the functional outcomes in childhood nystagmus. To conclude, children with nystagmus of types IINS, FMDN, SNS, or SN need to be managed differently. It is thus possible to timely manage these children, not only to save their life and improve their vision but also to improve their living quotient.

Utility of Gait Biofeedback Training to Improve Walking Biomechanics in Patients With Chronic Ankle Instability: A Critically Appraised Topic.

Chronic ankle instability (CAI) is a condition that involves feelings of the ankle "giving way," pain, and decreased self-reported function. Individuals with CAI often demonstrate persistent biomechanical impairments during gait that are associated with repetitive lateral ankle sprains (LAS) and the development of early onset ankle posttraumatic osteoarthritis (OA). Traditional rehabilitation strategies have not successfully improved these reported aberrant gait biomechanics; thus, traditional rehabilitation may not effectively reduce the risk of recurrent LAS and ankle OA among individuals with CAI. Conversely, targeted gait training with biofeedback may be effective at decreasing the risk of recurring LAS and ankle OA if these rehabilitation strategies can promote individuals with CAI to develop a gait strategy that protects against subsequent LAS and ankle OA. Can targeted gait biofeedback interventions cause individuals with CAI to implement a walking gait pattern that is not associated with recurrent LAS and ankle OA? Five studies assessed gait biofeedback interventions targeting plantar pressure and/or ankle kinematics involving visual biofeedback (n = 3), auditory biofeedback (n = 1), and haptic biofeedback (n = 1). Plantar pressure was medially shifted during a single session while receiving biofeedback (n = 2), immediately after biofeedback (n = 1), and 5 minutes after receiving biofeedback (n = 1) in 3 studies. One study demonstrated reduced ankle inversion after 8 sessions of biofeedback training. One study did not substantially improve plantar pressure while receiving visual feedback. Targeted gait training strategies appear effective in acutely altering gait biomechanics in individuals with CAI while receiving, and immediately after, biofeedback has been removed. Long-term outcomes are not currently established for gait training strategies in those with CAI. Limited evidence (grade B) suggests that targeted gait biofeedback strategies can alter specific CAI gait biomechanics to a strategy not associated with recurrent LAS, and ankle OA immediately, and after, multiple sessions of gait training.

Effects of gait training with auditory biofeedback on biomechanics and talar cartilage characteristics in individuals with chronic ankle instability: A randomized controlled trial

BackgroundAltered walking gait is a typical impairment following ankle sprains which may increase susceptibility to recurring injuries and development of posttraumatic osteoarthritis at the ankle. There is a lack of targeted gait training interventions focusing on specific modifications in individuals with chronic ankle instability (CAI). Additionally, there is a need to focus on cartilage health changes following gait training to mitigate osteoarthritis progression. Research questionTo determine the immediate and retention effects of gait training using auditory biofeedback (AudFB) in patients with chronic ankle instability (CAI) on biomechanics and talar cartilage characteristics. MethodsEighteen participants with CAI were randomly assigned into Control (n = 7) or AudFB (n = 11) groups. Each group completed 8-sessions of 30-minute treadmill walking. The AudFB group received biofeedback through a pressure sensor fashioned to the lateral foot and instructions to walk while avoiding noise from the sensor. The Control group did not receive instructions during sessions. An in-shoe insole system measured peak pressure, maximum force, and center of the pressure gait line (COP) during walking. Ultrasonography captured talar cartilage thickness and echo intensity before and after walking. Biomechanics and ultrasound were measured at baseline, immediately, and 1-week after the intervention. Repeated measures mixed-methods analysis of variance assessed changes within groups across time. ResultsThe AudFB group significantly reduced pressure and force in the lateral foot and medially shifted their COP at Immediate and 1-week Post. There were no observed changes in the Control group. In addition, neither group demonstrated changes in ultrasound measures at follow-up. SignificanceImplementation of auditory biofeedback during gait training can be a valuable tool for clinicians treating patients with CAI.

Effects of Vibrotactile Biofeedback Providing Real-Time Pressure Information on Static Balance Ability and Weight Distribution Symmetry Index in Patients with Chronic Stroke.

Training with visual and auditory biofeedback, in patients with stroke, improved balance ability and asymmetric posture. We developed a new biofeedback training device to prevent falls and improve balance ability in patients with stroke. This device corrects motion errors by collecting the pressure information of patients in real-time. This randomized crossover study aimed to investigate the effect of this biofeedback training on the static balance ability and weight distribution symmetry index in 24 patients with chronic stroke. Pressure sensor-based vibrotactile biofeedback, visual biofeedback providing posture information, and standing without biofeedback were randomly applied for 1 d each with 24 h washout intervals to minimize adaptation. The static balance ability was measured for each biofeedback training type, and the weight distribution symmetry index was calculated using the collected weight-bearing rate data. The static balance ability and weight distribution symmetry index differed significantly according to the type of biofeedback training used. Post-hoc analysis revealed significant differences in the order of newly developed vibrotactile biofeedback, visual biofeedback, and standing without biofeedback. These findings provide evidence that pressure sensor-based vibrotactile biofeedback improves static balance ability and weight support rates by proposing better intervention for patients with chronic stroke in the clinical environment.

The Short-Term Effects of Rhythmic Vibrotactile and Auditory Biofeedback on the Gait of Individuals After Weight-Induced Asymmetry.

Biofeedback (BFB), the practice of providing real-time sensory feedback has been shown to improve gait rehabilitation outcomes. BFB training through rhythmic stimulation has the potential to improve spatiotemporal gait asymmetries while minimizing cognitive load by encouraging a synchronization between the user's gait cycle and an external rhythm. The purpose of this work was to evaluate if rhythmic stimulation can improve the stance time symmetry ratio (STSR) and to compare vibrotactile to auditory stimulation. Gait parameters including velocity, cadence, stride length, double support time, and step length symmetry, were also examined. An experimental rhythmic stimulation system was developed, and twelve healthy adults (5 males), age 28.42 ± 10.93 years, were recruited to participate in walking trials. A unilateral ankle weight was used to induce a gait asymmetry to simulate asymmetry as commonly exhibited by individuals with lower limb amputation and other clinical disorders. Four conditions were evaluated: 1) No ankle weight baseline, 2) ankle weight without rhythmic stimulation, 3) ankle weight + rhythmic vibrotactile stimulation (RVS) using alternating motors and 4) ankle weight + rhythmic auditory stimulation (RAS) using a singletone metronome at the participant's self-selected cadence. As expected the STSR became significantly more asymmetrical with the ankle weight (i.e. induced asymmetry condition). STSR improved significantly with RVS and RAS when compared to the ankle weight without rhythmic stimulation. Cadence also significantly improved with RVS and RAS compared to ankle weight without rhythmic stimulation. With the exception of double support time, the other gait parameters were unchanged from the ankle weight condition. There were no statistically significant differences between RVS and RAS. This study found that rhythmic stimulation can improve the STSR when an asymmetry is induced. Moreover, RVS is at least as effective as auditory stimulation in improving STSR in healthy adults with an induced gait asymmetry. Future work should be extended to populations with mobility impairments and outside of laboratory settings.

Two-Week Rehabilitation with Auditory Biofeedback Prosthesis Reduces Whole Body Angular Momentum Range during Walking in Stroke Patients with Hemiplegia: A Randomized Controlled Trial.

Walking rehabilitation is challenging in stroke patients with sensory impairments. In this study, we examined the two-week effect of an auditory biofeedback prosthesis, Auditory Foot (AF), on the change in the frontal whole body angular momentum (WBAM) range, before and after a two-week walking rehabilitation. We conducted a pilot randomized controlled trial (RCT). We employed statistical Bayesian modeling to understand the mechanism of the rehabilitation effect and predict the expected effect in new patients. The best-performing model indicated that the frontal WBAM range was reduced in the AF group by 12.9–28.7%. This suggests that the use of kinesthetic biofeedback in gait rehabilitation contributes to the suppression of frontal WBAM, resulting in an improved walking balance function in stroke patients.

Motor learning on postural control using auditory biofeedback training

Motor disorders are characterised by damage to the central nervous system, which subsequently affects muscles, motor skills and brain function. People with motor disorders can suffer injury as a result of falls and recovery from falls can be challenging. Augmented biofeedback modalities is an important tool used in physical therapy, providing individuals with biofeedback that helps guide them through the therapy. Biofeedback modalities have been designed for most of our senses, including auditory, visual and haptic and advances in technology have meant that biofeedback therapy can make use of wearable technology and future advances are expected to further assist. Therefore, it will be key to determine which biofeedback method works best for different training exercises and conditions in order to maximise the benefits of technological advances. Dr Naoya Hasegawa and Professor Tadayoshi Asaka are investigating which biofeedback method works best for different therapies. Their goal is to understand the characteristics of sensory modalities used for biofeedback training in order to help physical therapists determine appropriate approaches for different individuals. The researchers are currently investigating postural control with a view to defining the characteristics of postural control during walking and standing and developing new methods to enhance or improve it. This work involves the use of force plates, 3D motion analysis systems and electromyograms.

Evaluating a wearable biofeedback device for reducing end-range sagittal lumbar spine flexion among home caregivers

Caregivers who work in the home environment are at risk of back injury due to the awkward postures they have to adopt while providing care. Real-time biofeedback provided by a recently developed wearable device (PostureCoach) may be able to reduce this risk. The effectiveness of a two-day training intervention (including PostureCoach and an educational video) was evaluated for its ability to decrease the amount of time spent in end-range spine flexion. Twenty novice caregivers repeated a series of simulated care tasks. Real-time auditory biofeedback was provided to the intervention group (n = 10) when participants’ sagittal lumbar spine flexion exceeded a preset threshold during training trials. Participants in the control group (n = 10) received no feedback. Participants repeated the tasks again two weeks and two months post-intervention. The intervention group maintained decreased end-range (80th and 95th percentile) spine flexion compared to controls at both post-intervention time points.

Usability Assessment of the Rehabilitation Lower-limb Orthopedic Assistive Device by Service Members and Veterans With Lower Limb Loss.

Telehealth is an increasingly common approach to improve healthcare delivery, especially within the Veterans Health Administration and Department of Defense (DoD). Telehealth has diminished many challenges to direct access for clinical follow-up; however, the use of mobile telehealth for specialty rehabilitative care is emerging and is referred to as telerehabilitation. As early adopters of telehealth, the Veterans Affairs and DoD have supported collaborated efforts for programs designed to increase the access and quality of rehabilitative care while improving the functional ability of our service members (SMs) and veterans with lower limb amputation (LLA). The DoD and Veterans Health Administration collaborated on a Mobile Device Outcomes-based Rehabilitation Program (MDORP) to help injured SMs and veterans with LLA. The MDORP project utilized a mobile health system called the Rehabilitative Lower Limb Orthopedic Accommodating Device (ReLOAD) to assess walking quality. The ReLOAD system includes real-time auditory biofeedback to notify the user of their most prominent gait deviation and then recommends exercises that address specific balance and strength impairments. The purpose of this study was to describe the responses to a postintervention survey evaluating the feasibility and usability of ReLOAD completed by SMs and veterans with LLA who used the system for 5 months. A link to an anonymous usability survey was emailed to all participants who completed MDORP. The survey was modeled after the System Usability Scale, with agreeableness to items rated on a 5-point Likert-style questionnaire in addition to open feedback. Data visualization of Likert-style questionnaires was conducted using ggplot2 and reshape2 statistical packages and was analyzed using R. We obtained institutional review board approval through both Miami Veterans Affairs Healthcare System and Walter Reed National Military Medical Center. The majority of participants reported that they would use the system again for home rehabilitation (65%) and that auditory biofeedback helped them walk better (59%). Participants also suggested that future work should include a greater variety of exercise options and the use of smart phones for the ReLOAD application in addition to the iPad tablet. The participants provided positive and constructive feedback that will enhance the value and usability of telerehabilitation interventions like the ReLOAD system for future users.

Biomechanical Response to External Biofeedback During Functional Tasks in Individuals With Chronic Ankle Instability.

Altered biomechanics displayed by individuals with chronic ankle instability (CAI) is a possible cause of recurring injuries and posttraumatic osteoarthritis. Current interventions are unable to modify aberrant biomechanics, leading to research efforts to determine if real-time external biofeedback can result in changes. To determine the real-time effects of visual and auditory biofeedback on functional-task biomechanics in individuals with CAI. Crossover study. Laboratory. Nineteen physically active adults with CAI (7 men, 12 women; age = 23.95 ± 5.52 years, height = 168.87 ± 6.94 cm, mass = 74.74 ± 15.41 kg). Participants randomly performed single-limb static balance, step downs, lateral hops, and forward lunges during a baseline and 2 biofeedback conditions. Visual biofeedback was given through a crossline laser secured to the dorsum of the foot. Auditory biofeedback was given through a pressure sensor placed under the lateral foot and connected to a buzzer that elicited a noise when pressure exceeded the set threshold. Cues provided during the biofeedback conditions were used to promote proper biomechanics during each task. We measured the location of center-of-pressure (COP) data points during balance with eyes open and eyes closed for each condition. Plantar pressure in the lateral column of the foot during functional tasks was extracted. Secondary outcomes of interest were COP area and velocity, time to boundary during static balance, and additional plantar-pressure measures. Both biofeedback conditions reduced COP in the anterolateral quadrant while increasing COP in the posteromedial quadrant of the foot during eyes-open balance. Visual biofeedback increased lateral heel pressure and the lateral heel and midfoot pressure-time integral during hops. The auditory condition produced similar changes during the eyes-closed trials. Auditory biofeedback increased heel pressure during step downs and decreased the lateral forefoot pressure-time integral during lunges. Real-time improvements in balance strategies were observed during both external biofeedback conditions. Visual and auditory biofeedback appeared to effectively moderate different functional-task biomechanics.

Biomechanical Response to External Biofeedback During Functional Tasks in Individuals With Chronic Ankle Instability

Altered biomechanics displayed by individuals with chronic ankle instability (CAI) is a possible cause of recurring injuries and posttraumatic osteoarthritis. Current interventions are unable to modify aberrant biomechanics, leading to research efforts to determine if real-time external biofeedback can result in changes. To determine the real-time effects of visual and auditory biofeedback on functional-task biomechanics in individuals with CAI. Crossover study. Laboratory. Nineteen physically active adults with CAI (7 men, 12 women; age = 23.95 ± 5.52 years, height = 168.87 ± 6.94 cm, mass = 74.74 ± 15.41 kg). Participants randomly performed single-limb static balance, step downs, lateral hops, and forward lunges during a baseline and 2 biofeedback conditions. Visual biofeedback was given through a crossline laser secured to the dorsum of the foot. Auditory biofeedback was given through a pressure sensor placed under the lateral foot and connected to a buzzer that elicited a noise when pressure exceeded the set threshold. Cues provided during the biofeedback conditions were used to promote proper biomechanics during each task. We measured the location of center-of-pressure (COP) data points during balance with eyes open and eyes closed for each condition. Plantar pressure in the lateral column of the foot during functional tasks was extracted. Secondary outcomes of interest were COP area and velocity, time to boundary during static balance, and additional plantar-pressure measures. Both biofeedback conditions reduced COP in the anterolateral quadrant while increasing COP in the posteromedial quadrant of the foot during eyes-open balance. Visual biofeedback increased lateral heel pressure and the lateral heel and midfoot pressure-time integral during hops. The auditory condition produced similar changes during the eyes-closed trials. Auditory biofeedback increased heel pressure during step downs and decreased the lateral forefoot pressure-time integral during lunges. Real-time improvements in balance strategies were observed during both external biofeedback conditions. Visual and auditory biofeedback appeared to effectively moderate different functional-task biomechanics.