Higher-order power harmonics of pulsed electrical stimulation modulates corticospinal contribution of peripheral nerve stimulation

Chiun Fan Chen, Marom Bikson, Li Wei Chou, Chunlei Shan, Niranjan Khadka, Wen Shiang Chen, Felipe Fregni*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


It is well established that electrical-stimulation frequency is crucial to determining the scale of induced neuromodulation, particularly when attempting to modulate corticospinal excitability. However, the modulatory effects of stimulation frequency are not only determined by its absolute value but also by other parameters such as power at harmonics. The stimulus pulse shape further influences parameters such as excitation threshold and fiber selectivity. The explicit role of the power in these harmonics in determining the outcome of stimulation has not previously been analyzed. In this study, we adopted an animal model of peripheral electrical stimulation that includes an amplitude-adapted pulse train which induces force enhancements with a corticospinal contribution. We report that the electrical-stimulation-induced force enhancements were correlated with the amplitude of stimulation power harmonics during the amplitude-adapted pulse train. In an exploratory analysis, different levels of correlation were observed between force enhancement and power harmonics of 20-80 Hz (r = 0.4247, p = 0.0243), 100-180 Hz (r = 0.5894, p = 0.0001), 200-280 Hz (r = 0.7002, p < 0.0001), 300-380 Hz (r = 0.7449, p < 0.0001), 400-480 Hz (r = 0.7906, p < 0.0001), 500-600 Hz (r = 0.7717, p < 0.0001), indicating a trend of increasing correlation, specifically at higher order frequency power harmonics. This is a pilot, but important first demonstration that power at high order harmonics in the frequency spectrum of electrical stimulation pulses may contribute to neuromodulation, thus warrant explicit attention in therapy design and analysis.

Original languageEnglish
Article number43619
JournalScientific reports
StatePublished - 3 Mar 2017


Dive into the research topics of 'Higher-order power harmonics of pulsed electrical stimulation modulates corticospinal contribution of peripheral nerve stimulation'. Together they form a unique fingerprint.

Cite this