Transcutaneous high-frequency alternating current for rapid reversible muscle force reduction below pain threshold

Abstract

Objective. The development of non-invasive, quickly reversible techniques for controlling undesired muscle force production (e.g. spasticity) could expand rehabilitation approaches in those with pathology by increasing the type and intensity of exercises that can be performed. High-frequency alternating current (HFAC) has been previously established as a viable method for blocking neural conduction in peripheral nerves. However, clinical application of HFAC for nerve conduction block is limited due to the invasiveness of surgical procedures and the painful onset response. This study aimed to examine the use of transcutaneous HFAC (tHFAC) at various stimulation frequencies to address these shortfalls. Approach. Ten individuals participated in the study. Surface electrodes were utilized to apply tHFAC (0.5–12 kHz) to the median and ulnar nerves. Individual pain threshold was determined by gradual increase of stimulation amplitude. Subjects then performed a force-matching task by producing grip forces up to the maximal voluntary contraction level with and without application of tHFAC below the pain threshold. Main results. Pain threshold current amplitude increased linearly with stimulation frequency. Statistical analysis showed that both stimulation frequency and charge injected per phase had significant effects (p < 0.05) on grip force reduction. At the group level, application of tHFAC below pain threshold reduced grip force by a maximum of 40.7% ± 8.1%. Baseline grip force trials interspersed between tHFAC trials showed consistent grip force, indicating that fatigue was not a factor in force reduction. Significance. Our results demonstrate the effectiveness of tHFAC at reducing muscle force when applied below the pain threshold, suggesting its potential clinical viability. Future studies are necessary to further elucidate the mechanism of force reduction before clinical application.

Kilohertz-frequency interferential current induces hypoalgesic effects more comfortably than TENS

“…TENS has been applied near the site of pain [31][32][33] . However, nerve conduction inhibition is the primary mechanism of TINI 11,34,35 . According to this concept, we applied TINI not to the location of pain but to the nerve that innervates the area of pain.…”

Kilohertz-frequency interferential current induces hypoalgesic effects more comfortably than TENS

“…Due to the differences in the neurological mechanisms of TENS and TINI, the application methods and electrode placement of the two electrical stimulations were different. TENS has been applied near the site of pain 35 – 37 , while TINI focuses on inhibiting nerve conduction 11 , 38 , 39 . In accordance with this concept, TINI has been applied not to the location of pain but to the nerve that innervates the area of pain.…”

Muscle Strength Weighting Based on Deep Learning and Wavelet Packet and Muscle Fatigue Analysis Based on L-Z Complexity

“…As a onedimensional time series signal, it can also reflect the characteristics of the neuromuscular system during muscle activity, which has the advantages of non-damaging and good locality [4]. [2,100] Hz, and its energy is mainly concentrated in the frequency range [5,50] Hz, showing the connection between muscle strength and the muscle sound signal. As the load increases, the peak value of the muscle sound signal increases.…”

“…Kim et al initially explored the connection between the generation method of muscle sound signal and muscle movement mechanism in the research based on muscle sound signal, laying a good foundation for subsequent researchers to study muscle sound signal[5]. Filli et al…”