Deakin University
Browse
nuzum-measurestopredict-2016.pdf (2.57 MB)

Measures to predict the individual variability of corticospinal responses following transcranial direct current stimulation

Download (2.57 MB)
Version 3 2024-06-17, 20:59
Version 2 2024-06-04, 03:03
Version 1 2016-11-28, 15:40
journal contribution
posted on 2024-06-17, 20:59 authored by ND Nuzum, AM Hendy, Aaron RussellAaron Russell, Wei-Peng TeoWei-Peng Teo
Individual responses to transcranial direct current stimulation (tDCS) are varied and therefore potentially limit its application. There is evidence that this variability is related to the contributions of Indirect waves (I-waves) recruited in the cortex. The latency of motor-evoked potentials (MEPs) can be measured through transcranial magnetic stimulation (TMS), allowing an individual's responsiveness to tDCS to be determined. However, this single-pulse method requires several different orientations of the TMS coil, potentially affecting its reliability. Instead, we propose a paired-pulse TMS paradigm targeting I-waves as an alternative method. This method uses one orientation that reduces inter- and intra-trial variability. It was hypothesized that the paired-pulse method would correlate more highly to tDCS responses than the single-pulse method. In a randomized, double blinded, cross-over design, 30 healthy participants completed two sessions, receiving 20 min of either anodal (2 mA) or sham tDCS. TMS was used to quantify Short interval intracortical facilitation (SICF) at Inter stimulus intervals (ISIs) of 1.5, 3.5 and 4.5 ms. Latency was determined in the posterior-anterior (PA), anterior-posterior (AP) and latero-medial (LM) coil orientations. The relationship between latency, SICF measures and the change in suprathreshold MEP amplitude size following tDCS were determined with Pearson's correlations. TMS measures, SICI and SICF were also used to determine responses to Anodal-tDCS (a-tDCS). Neither of the latency differences nor the SICF measures correlated to the change in MEP amplitude from pre-post tDCS (all P > 0.05). Overall, there was no significant response to tDCS in this cohort. This study highlights the need for testing the effects of various tDCS protocols on the different I-waves. Further research into SICF and whether it is a viable measure of I-wave facilitation is warranted.

History

Journal

Frontiers in Human Neuroscience

Volume

10

Season

Article number: 487

Article number

ARTN 487

Location

Switzerland

Open access

  • Yes

ISSN

1662-5161

eISSN

1662-5161

Language

English

Publication classification

C Journal article, C1 Refereed article in a scholarly journal

Copyright notice

2016, The Authors

Issue

OCT2016

Publisher

FRONTIERS MEDIA SA