Fig 1.
Six different configurations of the 12 contacts electrode were tested: Ring, tripolar transverse ring (TTR), tripolar transverse (TT), tripolar longitudinal ring (TLR), tripolar longitudinal (TL) and steering current ring (SCR).
Each configuration is composed of a unique active site (cathode) on the central ring B (red) and several return path (anode, blue) for which the current ratio is imposed [9]. Only one electrode conformation is presented here (cathode position). The row A is proximal to the spinal cord whereas the row C is distal.
Fig 2.
Setup description.
Fig 3.
Cuff electrode placed around the nerve.
Table 1.
Summary of the current intensities used for each rabbit.
Fig 4.
Different steps of the signal processing illustrated through data from Rabbit 1 with TTR configuration.
A example of CMAPs collected for each muscle, configuration TTR(B3). B Recruitment curves obtained after the computation of RMS: TTR(B3) (left) and TTR(B1) (right). C Selectivity curves obtained for TTR(B3) (left) and TTR(B1) (right). Missing point corresponds to data that could not be recorded.
Table 2.
Weight’s set used to compute the weighted cost function D.
Table 3.
Maximum SI obtained for each rabbit, configuration and muscle.
Bold numbers indicate that SIR is fulfilled.
Table 4.
Indexes are presented for each muscle and configuration (with optimal cathode conformation for each muscle).
Table 5.
Configuration occurrence as the optimal solution according to i) animal, ii) muscle, iii) weighted cost function D.
“Multiple” means that more than one configuration was found to be optimal (equal cost function D).
Table 6.
Configurations that reach the SIR criteria for the antagonist and agonist groups.