A wearable electromyography-controlled functional electrical stimulation system improves balance, gait function, and symmetry in older adults

Recognition of Human Lower Limb Motion and Muscle Fatigue Status Using a Wearable FES-sEMG System

Functional electrical stimulation (FES) devices are widely employed for clinical treatment, rehabilitation, and sports training. However, existing FES devices are inadequate in terms of wearability and cannot recognize a user's intention to move or muscle fatigue. These issues impede the user's ability to incorporate FES devices into their daily life. In response to these issues, this paper introduces a novel wearable FES system based on customized textile electrodes. The system is driven by surface electromyography (sEMG) movement intention. A parallel structured deep learning model based on a wearable FES device is used, which enables the identification of both the type of motion and muscle fatigue status without being affected by electrical stimulation. Five subjects took part in an experiment to test the proposed system, and the results showed that our method achieved a high level of accuracy for lower limb motion recognition and muscle fatigue status detection. The preliminary results presented here prove the effectiveness of the novel wearable FES system in terms of recognizing lower limb motions and muscle fatigue status.

Effects of Functional Electrical Stimulation on Gait Characteristics in Healthy Individuals: A Systematic Review

BACKGROUND

This systematic review aimed to provide a comprehensive overview of the effects of functional electrical stimulation (FES) on gait characteristics in healthy individuals.

METHODS

Six electronic databases (PubMed, Embase, Epistemonikos, PEDro, COCHRANE Library, and Scopus) were searched for studies evaluating the effects of FES on spatiotemporal, kinematic, and kinetic gait parameters in healthy individuals. Two examiners evaluated the eligibility and quality of the included studies using the PEDro scale.

RESULTS

A total of 15 studies met the inclusion criteria. The findings from the literature reveal that FES can be used to modify lower-limb joint kinematics, i.e., to increase or reduce the range of motion of the hip, knee, and ankle joints. In addition, FES can be used to alter kinetics parameters, including ground reaction forces, center of pressure trajectory, or knee joint reaction force. As a consequence of these kinetics and kinematics changes, FES can lead to changes in spatiotemporal gait parameters, such as gait speed, step cadence, and stance duration.

CONCLUSIONS

The findings of this review improve our understanding of the effects of FES on gait biomechanics in healthy individuals and highlight the potential of this technology as a training or assistive solution for improving gait performance in this population.

Whole-body vibration training does not improve the static balance of older women in the eyes-open state: A randomized trial

BACKGROUND: The impact of the current most effective vibration frequency on the balance ability of the elderly needs further verification. OBJECTIVE: To explore the effect of whole-body vibration training (WBVT) at three different frequencies on the balance ability of older women. METHODS: Ninety-three older women were randomly divided into low frequency (15 Hz), intermediate frequency (30 Hz), high-frequency (45 Hz), and control groups. The subjects in the vibration group underwent WBVT of the same amplitude twice a week for approximately 15 min per session. RESULTS: The speed of movement of the centre of pressure in the left and right directions with eyes closed was 7.9% lower in the static balance ability test in the intermediate frequency group after 36 weeks (P< 0.05). In the high frequency group, after WBVT, the total length of centre of pressure movement and speed of centre of pressure movement in the left and right directions were 9.9% and 8.7% lower, respectively, in the dynamic balance test (P< 0.05), and the speed of closed eye movement in the left and right directions was 12.5% lower in the static balance test (P< 0.05). CONCLUSION: WBVT at 30 and 45 Hz improved static balance in the right and left directions when older women had their eyes closed. WBVT at 45 Hz improved dynamic balance in the right and left directions in older women, and WBVT did not improve static balance in older women when their eyes were open.

Volitional EMG Estimation Method during Functional Electrical Stimulation by Dual-Channel Surface EMGs

We propose a novel dual-channel electromyography (EMG) spatio-temporal differential (DESTD) method that can estimate volitional electromyography (vEMG) signals during time-varying functional electrical stimulation (FES). The proposed method uses two pairs of EMG signals from the same stimulated muscle to calculate the spatio-temporal difference between the signals. We performed an experimental study with five healthy participants to evaluate the vEMG signal estimation performance of the DESTD method and compare it with that of the conventional comb filter and Gram–Schmidt methods. The normalized root mean square error (NRMSE) values between the semi-simulated raw vEMG signal and vEMG signals which were estimated using the DESTD method and conventional methods, and the two-tailed t-test and analysis of variance were conducted. The results showed that under the stimulation of the gastrocnemius muscle with rapid and dynamically modulated stimulation intensity, the DESTD method had a lower NRMSE compared to the conventional methods (p < 0.01) for all stimulation intensities (maximum 5, 10, 15, and 20 mA). We demonstrated that the DESTD method could be applied to wearable EMG-controlled FES systems because it estimated vEMG signals more effectively compared to the conventional methods under dynamic FES conditions and removed unnecessary FES-induced EMG signals.