Low-Frequency Stimulation More Efficient Than Kilohertz-Frequency in Stroke Rehabilitation: Study

A new study published in the PM & R: The Journal of Injury, Function, and Rehabilitation compared low-frequency and kilohertz-frequency electrical stimulation in stroke patients with arm paresis and found that low-frequency stimulation offers greater efficiency. Despite this, both types of stimulation produced similar outcomes in terms of generated force, patient discomfort, and fatigue levels.

Approximately 77% of survivors of stroke experience abnormalities in their upper limbs. Stroke is the third biggest cause of combined death and disability-adjusted life years lost globally. Activities of daily living are significantly impacted by arm paresis in particular. Notably, individuals with stroke have demonstrated significant improvements in strength and activity performance while receiving cyclic electrical stimulation, particularly functional electrical stimulation. Maximizing force output is essential for the successful use of electrical stimulation in therapeutic settings.

The strength of the stimulation, which may be raised based on the patient's tolerance, determines this, though. This research examined the effects of various electrical stimulation parameters, comparing low-frequency and kilohertz-frequency stimulation in healthy volunteers, due to the wide range of configuration possibilities available for electrical stimulation. This study compared the effects of low-frequency current and kilohertz frequency on electrically produced force, muscular fatigue, pain, and stimulation efficiency in stroke patients.

A total of 20 patients (7 females; mean ± SD: 66 ± 12 years; 176 ± 11 cm; 90 ± 19 kg; 57 ± 34 days after stroke) who had arm paresis following a stroke during the last 6 months were recruited, 21 were enrolled, and 20 finished the research. Over the course of 2 days (48-hour washout), each subject received both low-frequency and kilohertz stimulation in a randomized order. Every day consisted of a fatigue protocol (30 repetitions, 8 seconds of stimulation, 3 seconds of rest) and a step protocol with a progressive rise in stimulation intensity, beginning at the first measured force (up to 12 steps, 1 mA increments, 8 seconds of stimulation, 60 seconds of rest).

For low-frequency stimulation, linear-mixed-effects models demonstrated noticeably greater stimulation efficiency (mean difference 0.14 [95% CI, 0.01–0.27 N/mA], p =.031). Nevertheless, electrically produced force, degree of pain, and muscular exhaustion were not substantially impacted by current type (p >.05). Overall, stroke patients with arm paresis may benefit more from low-frequency and kilohertz-frequency electrical stimulation. 

Source:

Tenberg, S., Weinig, J., Niederer, D., Vogt, L., Leisse, M., & Müller, S. (2025). Effects of kilohertz versus low-frequency electrical stimulation of the wrist extensors in patients after stroke: A randomized crossover trial. PM & R: The Journal of Injury, Function, and Rehabilitation. https://doi.org/10.1002/pmrj.13368