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

• This randomized sham-controlled trial investigated anodal transcranial direct current stimulation (tDCS) over the somatosensory cortex contralateral to hand dominance for dose-response (1mA-20 minutes x 5 days) effects on vibrotactile detection thresholds (VDT). VDT was measured before and after tDCS on days 1,3&5 for low (30hz) and high (200hz) frequency vibrations on the dominant and non-dominant hands in 29 healthy adults (mean age = 22.86; 15 males, 14 females). Only the dominant hand 200Hz VDT displayed statistically significant medium effect size improvement for mixed model analysis of variance time x group interaction for active tDCS compared to sham. Post Hoc contrasts were statistically significant for dominant hand 200Hz VDT on day 5 after tDCS compared to day 1 before tDCS , day 1 after tDCS and day 3 before tDCS. There was a linear dose-response improvement with dominant hand 200Hz 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 non-dominant hand 30Hz VDT was statistically significant (p=0.03) though Post Hoc contrasts were non-significant after Sidak adjustment. No adverse effects for tDCS were reported. In conclusion, anodal tDCS 1mA-20 minutes x 5 days on the dominant sensory cortex can modulate a linear improvement of dominant hand high frequency VDT but not for low frequency or non-dominant hand VDT.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Fysiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Physiology (hsv//eng)

Nyckelord

Transcranial direct current stimulation

primary somatosensory cortex

vibrotactile detection threshold

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