Transcutaneous electrical nerve stimulation effects upon linear positioning performance.

Abstract

The effects of transcutaneous electrical nerve stimulation (TENS) upon linear-positioning performance was investigated. 30 right-handed subjects were trained and tested on a linear-positioning apparatus either under constant stimulus conditions or mixed stimulus—no-stimulus conditions. The nerve stimulation, administered by a Staodyn Model 4000 stimulator, was positioned to stimulate the brachial plexus. Subjects' task was to learn a position 300 mm along a trackway while blindfolded. 20 acquisition trials with knowledge of results, which consisted of a verbal report of the magnitude of the subjects' errors, were given followed by 20 retention trials without knowledge of results. During acquisition subjects receiving nerve stimulation required a greater number of trials to achieve asymptotic error reductions than subjects who did not receive this stimulation. However, during retention, the acquisition group, no longer receiving transcutaneous electrical nerve stimulation, consistently exhibited longer responses than control subjects. Subjects receiving the electrical stimulation for the first time during retention exhibited responses which were shorter than those exhibited by controls and acquisition-stimulated groups. Findings are discussed in terms of implications for motor-control mechanisms.