Fascicle-selective kilohertz-frequency neural conduction block with longitudinal intrafascicular electrodes.

Abstract

Objective: Electrical stimulation of peripheral nerves is used to treat a variety of disorders and conditions. While conventional biphasic pulse stimulation typically induces neural activity in fibres, kilohertz (kHz) continuous stimulation can block neural conduction, offering a promising alternative to drug-based therapies for alleviating abnormal neural activity. This study explores strategies to enhance the selectivity and control of high-frequency neural conduction block using intrafascicular electrodes.

Methods: In vivo experiments were conducted in a rodent model to assess the effects of kilohertz stimulation delivered via longitudinal intrafascicular electrodes on motor axons within the tibial and common peroneal fascicles of the sciatic nerve.

Main results: We demonstrated that a progressive and selective block of neural conduction is achievable with longitudinal intrafascicular electrodes. We showed that the amount of neural conduction block can be tuned by adjusting the amplitude and frequency of kilohertz stimulation. Additionally, we achieved interfascicular selectivity with intrafascicular electrodes, with this selectivity being modulated by the kilohertz stimulation frequency. We also observed a small amount of onset response spillover, which could be minimized by increasing the blocking stimulus frequency. Muscle fatigue was quantified during kHz continuous stimulation and compared to control scenarios, revealing that the muscle was able to recover from fatigue during the block, confirming a true block of motor neurons.

Significance: Our findings show that kilohertz stimulation using longitudinal intrafascicular electrodes can be precisely controlled to achieve selective conduction block. By leveraging existing knowledge from conventional stimulation techniques, this approach allows for the development of stimulation protocols that effectively block abnormal neural patterns with reduced side effects.