Characterization of multi-channel intraneural stimulation in transradial amputees

Abstract

Although peripheral nerve stimulation using intraneural electrodes has been shown to be an effective and reliable solution to restore sensory feedback after hand loss, there have been no reports on the characterization of multi-channel stimulation. A deeper understanding of how the simultaneous stimulation of multiple electrode channels affects the evoked sensations should help in improving the definition of encoding strategies for bidirectional prostheses. We characterized the sensations evoked by simultaneous stimulation of median and ulnar nerves (multi-channel configuration) in four transradial amputees who had been implanted with four TIMEs (Transverse Intrafascicular Multichannel Electrodes). The results were compared with the characterization of single-channel stimulation. The sensations were characterized in terms of location, extent, type, and intensity. Combining two or more single-channel configurations caused a linear combination of the sensation locations and types perceived with such single-channel stimulations. Interestingly, this was also true when two active sites from the same nerve were stimulated. When stimulating in multi-channel configuration, the charge needed from each electrode channel to evoke a sensation was significantly lower than the one needed in single-channel configuration (sensory facilitation). This result was also supported by electroencephalography (EEG) recordings during nerve stimulation. Somatosensory potentials evoked by multi-channel stimulation confirmed that sensations in the amputated hand were perceived by the subjects and that a perceptual sensory facilitation occurred. Our results should help the future development of more efficient bidirectional prostheses by providing guidelines for the development of more complex stimulation approaches to effectively restore multiple sensations at the same time.

Decoding of Pain Perception using EEG Signals for a Real-Time Reflex System in Prostheses: A Case Study

“…For all statistical analyses, we first checked the normality as well as the independence of the data before applying the adequate statistical test. The normality of the data (the three conditions with the background activity) was checked using one-sample Kolmogorov-Smirnov test, which is a strict normality test, and as was suggested in the study by Strauss et al 50 . Thereafter, the independence was checked using the Mann-Whitney U Test was used (used when data is not normally distributed) and we found that the conditions are statistically independent (p-value < 0.0001).…”

Sensitivity to temporal parameters of intraneural tactile sensory feedback

“…In TR, the inter-digit temporal distance between two active sites stimulation (multichannel stimulation) was changed. d Induced sensation and stimulation parameters were reported for ME and UE for Subject 1 and 2 and 120 μA, with a resolution of 10 μs) and increased the stimulation amplitude (from 10 μA to 980 uA, with a resolution of 20 μA) in order to find the perceptual thresholds [10,23]. Then, if the perceptual threshold was not found, we repeated the procedure with a higher pulse width (eg.…”

“…The results of the single-channel and multi-channel characterization procedures are described in [6,23]. For this study, two active sites of two electrodes (one in the median nerve and one in the ulnar nerve) were chosen to elicit two well-perceivable, stable, and spatially-separated sensations referred on the phantom hand ( Fig.…”

Generating Artificial Sensations with Spinal Cord Stimulation in Primates and Rodents

“…However, stimulating these brain areas requires surgical implantation of deep intracranial electrodes -a procedure associated with significant risks. While peripheral nerve stimulation provides a less invasive alternative, sensations evoked with this method are highly localized, and thus limited in their applicability as a general-purpose sensory input pathway to the brain (11)(12)(13).…”