Dose response of somatosensory cortex repeated anodal transcranial direct current stimulation on vibrotactile detection: a randomized sham-controlled trial

作者：Folmli Brookes; Turman Bulent; Johnson Peter; Abbott Allan^*

来源：Journal of Neurophysiology, 2018, 120(2): 610-616.

DOI：10.1152/jn.00926.2017

• primary somatosensory cortex
• transcranial direct current stimulation
• vibrotactile detection threshold

This randomized sham-controlled trial investigated anodal transcranial direct current stimulation (tDCS) over the somatosensory cortex contralateral to hand dominance for dose-response (1 mA, 20 min X 5 days) effects on vibrotactile detection thresholds (VDT). VDT was measured before and after tDCS on days 1,3, and 5 for low- (30 Hz) and high-frequency (200 Hz) vibrations on the dominant and nondominant hands in 29 healthy adults (mean age = 22.86 yr; 15 men. 14 women). Only the dominant-hand 200-Hz VDT displayed statistically significant medium effect size improvement for mixed-model analysis of variance time-by-group interaction for active tDCS compared with sham. Post hoc contrasts were statistically significant for dominant-hand 200-Hz VDT on day 5 after tDCS compared with day 1 before IDCS, day 1 after tDCS, and day 3 before tDCS. There was a linear dose-response improvement with dominant-hand 200-Hz VDT mean difference decreasing from day 1 before tDCS peaking at -15.5%, (SD = 34.9%) on day 5 after tDCS. Both groups showed learning effect trends over time for all VDT test conditions, but only the nondominant-hand 30-Hz VDT was statistically significant (P = 0.03). although post hoc contrasts were nonsignificant after Sidak adjustment. No adverse effects for tDCS were reported. In conclusion, anodal tDCS at 1 mA, 20 min X 5 days on the dominant sensory cortex can modulate a linear improvement of dominant-hand high-frequency VDT but not low-frequency or nondominant-hand VDT.
NEW & NOTEWORTHY Repeated weak anodal transcranial direct current stimulation (1 mA, 20 min) on the dominant sensory cortex provides linear improvement in dominant-hand high-frequency vibration detection thresholds. No effects were observed for low-frequency or nondominant-hand vibration detection thresholds.

• 出版日期2018-8