24-channel transcutaneous electrical sensory stimulation of the forearm: Effects on cognitive performance and autonomic arousal compared with single-electrode stimulation

Abstract

We sought to establish the effects on cognitive performance and autonomic arousal of a multi-electrode transcutaneous electrical sensory stimulator compared with single-electrode stimulation. Progressing from a feasibility study (n = 10) to a repeated-measures, within-subject study (n = 67), healthy, right-handed participants (34 male, mean age 28 ± 11.5 yrs.) received four separate predictable (“lines” or “ring”) or unpredictable (“fly” or “random”) complex electrical stimulation patterns to the non-dominant forearm via 24 individually programmable electrodes, or single-electrode stimulation. During stimulation, participants in the main study performed a series of cognitively demanding tests or a two-point discrimination task and had their autonomic arousal (skin conductance response) monitored. Single-electrode “first felt” current intensity decreased from distal to proximal forearm, was positively correlated with forearm circumference and was lower in females. Single-electrode stimulation was associated with a significant decline in two-point discrimination performance. There were no significant autonomic arousal or cognitive performance differences between complex patterns, but all patterns were associated with greater autonomic arousal than single-electrode stimulation. In conclusion, gender and forearm location and circumference significantly influence perception-levels for electrical current. Future research should examine whether the induction of increased autonomic arousal, via multi-electrode complex patterns, has improved therapeutic application, compared with single-electrode stimulation.

Keywords

• transcutaneous electrical sensory stimulation
• complex patterns
• rehabilitation
• salience
• attention
• cognitive interference