Novel Alternative Stimulation of Old Traditional Target: Closed-loop Stimulation
In the 'standard' DBS technique, a stimulus is delivered to a brain target at predefined electrical parameters, independently by ongoing neural activity. This can be a very important limit of DBS, for example, by depleting current when not needed. Recently, an alternative adaptive paradigm of stimulation has been proposed, the so-called closed-loop stimulation. According to this novel adaptive paradigm, stimulation is real-time adjusted to the ongoing neural activity, such as oscillatory activity. Lately, the effects of 'closed-loop' GPi stimulation have been investigated in two MPTP parkinsonian monkeys. A closed-loop system allows automatically changing the output based on the difference between the feedback signals to the input signals. Closed-loop stimulation determined a dramatic decrease of discharge rate, virtually abolishing the oscillatory activity, and allowing a greater improvement of akinesia compared with the standard GPi 'open-loop' paradigm of stimulation.
A wireless instantaneous neurochemical concentration sensor (WINCS), a device allowing near-real time detection of neurochemical changes, has been recently developed. In a near future, the WINCS could integrate a closed-loop DBS system as electrochemical feedback, which would allow a better adaptation of stimulation parameters.
These preliminary results seem promising and encourage new investigations to determine the safety, feasibility and efficacy of this closed-loop paradigm in humans.
Expert Rev Neurother. 2013;13(12):1319-1328. © 2013 Expert Reviews Ltd.