Development of a novel biofeedback system for the sprint start

This study developed and evaluated a novel concurrent biofeedback system for the sprint start. Previous studies have investigated sprint start biofeedback applications, but these have either not considered important kinematics, coaching implications or key motor learning principles. The biofeedback system was developed to convey rear knee angle information, obtained from 3D motion capture to novice participants as changes in the colour of an LED start line when they were in the “set” position. Based on initial user feedback, the system indicated whether the participants’ rear knee angles were within ± 2° of 130° (green) or not (red). A two-group experimental study was then employed to explore the acute responses of novices to the use of the biofeedback system during the sprint start. When exposed to biofeedback, the experimental group (EXP, n = 10) exhibited less deviation (4.0 ± 2.4°) from the target rear knee angle than they did in either a pre-test (11.9 ± 6.9°) or post-test (10.4 ± 4.4°) condition without biofeedback. The control group (CON, n = 10) with no biofeedback exhibited greater deviation from the target rear knee angle than the EXP group in all three condition blocks (pre-test = 21.8 ± 15.1°, no intervention = 15.6 ± 7.3°, post-test = 14.3 ± 6.5°) but the group × condition interaction effect was not significant (P = 0.210). The novel biofeedback system can be used to manipulate selected “set” position kinematics and has the potential to be incorporated with different input systems (e.g. inertial measurement units (IMUs)) or in longitudinal designs.

EXPLORATION OF VIBROTACTILE BIOFEEDBACK STRATEGIES TO INDUCE STANCE TIME ASYMMETRIES

BACKGROUND: Gait symmetry is the degree of equality of biomechanical parameters between limbs within a gait cycle. Human gait is highly symmetrical; however, in the presence of pathology, gait often lacks symmetry. Biofeedback (BFB) systems have demonstrated the potential to reduce gait asymmetry, improve gait function, and benefit overall long-term musculoskeletal health. OBJECTIVE(S): The aim of this study was to develop a BFB system and evaluate three unique BFB strategies, including bidirectional control – constant vibration (BC), bidirectional control – variable vibration (BV), and unidirectional control – variable vibration (UV) relevant to gait symmetry. The assessed feedback strategies were a combination of vibration frequency/amplitude levels, vibration thresholds, and vibrotactile stimuli from one and two vibrating motors (tactors). Learning effect and short-term retention were also assessed. METHODOLOGY: Testing was performed using a custom BFB system that induces stance time asymmetries to modulate temporal gait symmetry. The BFB system continuously monitors specific gait events (heel-strike and toe-off) and calculates the symmetry ratio, based on the stance time of both limbs to provide real-time biomechanical information via the vibrating motors. Overall walking performance of ten (n=10) able-bodied individuals (age 24.8 ± 4.4 years) was assessed via metrics of symmetry ratio, symmetry ratio error, walking speed, and motor's vibration percentages. FINDINGS: All participants utilized BFB somatosensory information to modulate their symmetry ratio. UV feedback produced a greater change in symmetry ratio, and it came closer to the targeted symmetry ratio. Learning or short-term retention effects were minimal. Walking speeds were reduced with feedback compared to no feedback; however, UV walking speeds were significantly faster compared to BV and BC. CONCLUSION: The outcomes of this study provide new insights into the development and implementation of feedback strategies for gait retraining BFB systems that may ultimately benefit individuals with pathological gait. Future work should assess longer-term use and long-term learning and retention effects of BFB systems in the populations of interest. Layman's Abstract Healthy walking is usually highly symmetrical with the same movements occurring on both sides of the body. However, certain disorders can cause abnormal and asymmetrical walking movements. Biofeedback can improve the movements during walking. This study used a custom biofeedback system to test three ways of applying biofeedback including having one and two motors that vibrated in unique ways. The biofeedback system was set up to guide participants to change their normal walking pattern to be less symmetrical. Walking movements of ten young able-bodied individuals were measured while walking with the biofeedback system. The results showed a change in walking symmetry for all participants. Using a single vibrating motor resulted in the greatest changes in walking symmetry. The changes in walking symmetry occurred only when using biofeedback, and walking patterns quickly returned to normal when the biofeedback was turned off. Overall, all feedback methods caused the users to walk slower than their typical walking speed. These findings provide important new information about the changes in walking caused by different biofeedback methods. Future work should evaluate long-term effects of biofeedback methods in the populations of interest. Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/36744/28677 How To Cite: Escamilla-Nunez R, Sivasambu H, Andrysek J. Exploration of vibrotactile biofeedback strategies to induce stance time asymmetries. Canadian Prosthetics & Orthotics Journal. 2022; Volume 5, Issue 1, No.2. https://doi.org/10.33137/cpoj.v5i1.36744 Corresponding Author: Rafael Escamilla-Nunez, Institute of Biomedical Engineering, University of Toronto, Toronto, Canada.E-Mail: [email protected] ID: https://orcid.org/0000-0002-2739-878X

Exploring Students’ Perceived Attitude on Utilizing a Biofeedback System for Anxiety Awareness during Academic Examination Activities

The presented paper examines the students’ adoption of the use of a cost-effective biofeedback system for anxiety awareness in parallel to examination activities. Human anxiety is classified by evaluating bio-signals related to skin conductance, skin temperature and heart rate. The participants of the research were 44 students who were taking examinations in the form of synchronous online tests in the classroom for one of their courses. At first, the usability of the biofeedback system was examined using the system usability scale (SUS). The statistical analysis indicated that the examined system usability is quite satisfactory. Then, the study attempted to investigate the relationships between the students’ technology readiness personality dimensions, perceptions of usability, and the usefulness of the presented system by exploiting the technology readiness and acceptance model (TRAM). The results showed that the students’ optimism and attitude towards using the system are significant factors that affect the model’s relationships. The examined relationships are presented via a path model.

Development and usability of biofeedback system for water resistance therapy using sensor

Purpose: The purpose of this study was to develop a water cup device for voice therapy as a biofeedback device for water resistance therapy (WRT), one of the semi-occluded vocal tract exercises (SOVTEs) using sensors. In addition, we explore the usefulness of the system for training in voice therapy by implementing water resistance phonation through newly developed devices.Methods: Using Arduino, the water resistance value was measured using a water level sensor, and a system was developed to visually implement the water resistance value and duration of exhalation and vocalization according to the change in water level caused by bubbles. Visual feedback was provided using LED sensors that represent colors according to the height of the water level. The WRT step was performed on six normal adults (male 3 and female 3) to implement changes in water level change amplification rate according to tube diameter and depth, and quantitatively analyzed.Results: The experiment showed that different LED colors were displayed depending on the resistance value of the water level. The LED’s brightness decreased as the width of the silicone tube diameter became larger in the bubble according to the tube diameter. Moreover, compared to 5 mm or 7 mm, a tube diameter of 10 mm showed the lowest amplification rate, regardless of with or without phonation. A depth of 2 cm, with the tube tip submerged in water, demonstrated the lowest amplification rate with or without phonation, compared to 4, 7, and 10 cm.Conclusions: The newly developed cup device for water resistance therapy was easy to give visual feedback according to changes in water level and helped to identify objectively by quantifying the performance of the target. This system may help clinicians and patients not only in clinical situations but also in practice at home during voice training.

Immediate and Lasting Effect of Cryoflow (IR Guided) on Pain in Patients with Frozen Shoulder: An Interventional Study

Background: Frozen shoulder is a painful and debilitating condition with an occurrence of 3% to 5% in the general population and up to 20% in those with diabetes. Physiotherapy has been established to be very effective in treatment of frozen shoulder. “Cryoflow IR machine is the first cryotherapy apparatus for cooling down free surrounding air with a biofeedback system, thereby it ensures a steady temperature on a treated area”. Hence, this study was conducted to study the immediate and lasting effect of Cryoflow (IR guided) on pain in patients with frozen shoulder. Aims and Objectives: To study an immediate and lasting effect of Cryoflow (IR guided) on pain in patients with frozen shoulder. Methodology: 15 patients of frozen shoulder were included by convenience sampling after taking ethical approval for the present study. The patients were given Cryoflow (IR guided) for 10 minutes. Study Duration was of 1 month. Pre and post interventional outcome measures in terms of VAS score at rest and during activity were evaluated immediately and after 24 hours of treatment. Results: Patients showed significant improvement when pre and post data were analyzed for VAS score at rest and during activity. (p< 0.05). Conclusion: Cryoflow (IR guided) has significant immediate and lasting effect (after 24 hrs) on pain at rest and on activity in patients with frozen shoulder. Key words: Frozen shoulder, Pain, Cryoflow (IR guided).

A Two Joint Neck Model to Identify Malposition of the Head Relative to the Thorax

Neck pain is a frequent health complaint. Prolonged protracted malpositions of the head are associated with neck pain and headaches and could be prevented using biofeedback systems. A practical biofeedback system to detect malpositions should be realized with a simple measurement setup. To achieve this, a simple biomechanical model representing head orientation and translation relative to the thorax is introduced. To identify the parameters of this model, anthropometric data were acquired from eight healthy volunteers. In this work we determine (i) the accuracy of the proposed model when the neck length is known, (ii) the dependency of the neck length on the body height, and (iii) the impact of a wrong neck length on the models accuracy. The resulting model is able to describe the motion of the head with a maximum uncertainty of 5 mm only. To achieve this high accuracy the effective neck length must be known a priory. If however, this parameter is assumed to be a linear function of the palpable neck length, the measurement error increases. Still, the resulting accuracy can be sufficient to identify and monitor a protracted malposition of the head relative to the thorax.

A Breathing Sonification System to Reduce Stress During the COVID-19 Pandemic

Since sound and music are powerful forces and drivers of human behavior and physiology, we propose the use of sonification to activate healthy breathing patterns in participants to induce relaxation. Sonification is often used in the context of biofeedback as it can represent an informational, non-invasive and real-time stimulus to monitor, motivate or modify human behavior. The first goal of this study is the proposal and evaluation of a distance-based biofeedback system using a tempo- and phase-aligned sonification strategy to adapt breathing patterns and induce states of relaxation. A second goal is the evaluation of several sonification stimuli on 18 participants that were recruited online and of which we analyzed psychometric and behavioral data using, respectively questionnaires and respiration rate and ratio. Sonification stimuli consisted of filtered noise mimicking a breathing sound, nature environmental sounds and a musical phrase. Preliminary results indicated the nature stimulus as most pleasant and as leading to the most prominent decrease of respiration rate. The noise sonification had the most beneficial effect on respiration ratio. While further research is needed to generalize these findings, this study and its methodological underpinnings suggest the potential of the proposed biofeedback system to perform ecologically valid experiments at participants' homes during the COVID-19 pandemic.