Perceptual improvement following repetitive sensory stimulation depends monotonically on stimulation intensity.

Author: Schlieper S, Dinse HR.
Affiliation:
Institut fur Neuroinformatik, Neural Plasticity Lab, Ruhr-University-Bochum, Germany.
Conference/Journal: Brain Stimul.
Date published: 2012 Oct
Other: Volume ID: 5 , Issue ID: 4 , Pages: 647-51 , Special Notes: doi: 10.1016/j.brs.2011.07.002 , Word Count: 190



BACKGROUND:
Electrical repetitive sensory stimulation (rSS) is a direct and effective means of inducing plasticity processes in human beings, and is increasingly being used as a therapeutic intervention. Suprathreshold intensities induce beneficial effects on tactile perception and sensorimotor abilities. However, it is not known whether there is an optimal range of stimulus intensity.
METHODS:
We investigated the effect of varied intensities (low, 1.19 ± 0.07 mA; intermediate, 3.33 ± 0.27 mA; and high, 4.42 ± 0.56 mA) on the outcome of a 30-minute electrical rSS applied to the index finger (intermittent high-frequency stimulation, 20 Hz and interburst interval, 5 seconds) in three groups (n = 10 each) of participants. As a marker of perceptual changes, we measured tactile spatial two-point discrimination on the stimulated finger and on the heel of the hand before and after the rSS.
RESULTS:
rSS improved discrimination performance, with the gain being the highest in the high-intensity group and the lowest in the low-intensity group. Measurements on the heel of the hand revealed small improvements in the high-intensity group, indicative of recruitment processes.
CONCLUSIONS:
rSS of maximal intensity induced the strongest effects, indicative of a monotonic intensity-gain characteristic with no U-shaped dependency.
Copyright © 2012 Elsevier Inc. All rights reserved.
PMID: 21962984

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