Electrode evaluation for selective stimulation of nerve fibres
Research type
Research Study
Full title
Investigation into the characteristic recruitment properties of a custom engineered electrode for the selective activation of nerve fibres according to nerve fibre diameter
IRAS ID
324847
Contact name
Dennis Fitzpatrick
Contact email
Sponsor organisation
University of East Anglia
Duration of Study in the UK
2 years, 7 months, 1 days
Research summary
Functional Electrical Stimulation (FES) can be used to artificially stimulate muscle movement in paralysed limbs. Different leg muscles will be recruited according to motor unit size which is dependant on the diameter of the nerve fibres innervating the muscle. However, using current FES methods, there is a problem with an unnatural inverse recruitment of muscle units in that muscles which fatigue the fastest will be recruited in preference to slow muscle units which fatigue more slowly. Fast muscles are effective for short bursts of powerful activity as seen by sprinters compared to long distance runners which have developed slow muscle fatigue resistant muscle groups. In normal gait, the slow muscle units are recruited in preference to the fast muscle units.
Being able to demonstrate a natural recruitment of nerve fibres is also beneficial for the restoration of bladder function. The smooth bladder muscle wall is innervated by relatively small diameter nerve fibres compared to larger diameter nerve fibres which innervate the fast striated muscle of the external sphincter. Consequently it is imperative for an FES system to selectively activate the small diameter nerve fibres which will effect a contraction of the bladder wall prior to the activation of the external sphincter which will relax thus effecting a more natural evacuation of the bladder. There is also a requirement for the stimulating cuff electrode to effect a one way propagation of nerve action potentials. This is to minimise the activation of nerve fibres that innervate sensory and nerve pain receptors.
The research work builds upon previous research work in which selective blocking and activation of nerve fibres was demonstrated using hand made electrodes. This research uses 3D printed electrodes in which the electrode is made to more exacting dimensions to control the selective activation of distinct nerve fibre populations.REC name
HSC REC B
REC reference
23/NI/0044
Date of REC Opinion
26 Apr 2023
REC opinion
Further Information Favourable Opinion