Gregoriou, Evridiki;
(2022)
Optimising the Application of Transcranial Direct Current Stimulation.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
The ability of transcranial direct current stimulation (tDCS) to modulate brain activity has vast scientific and therapeutic potential, however, its effects are often variable which limit its utility. Both current flow direction and variance in electric field intensities reaching a cortical target may be vital sources of the variable tDCS effects on neuroplastic change. Controlling for these and exploring the subsequent effects on corticospinal excitability is the aim of this thesis. I here attempted to optimise the delivery of tDCS application by investigating the controlled application of current flow direction and whether through the use of current flow models, we can deliver comparable electric fields with reduced variability across differential montages. To assess whether current flow models are useful, I further investigated if dose-control translates to more consistent physiological outcomes. I demonstrate, firstly, that different current flow directions did not differentially affect the two banks of the central sulcus. Secondly, with the use of dose-control, high-definition tDCS (HD-tDCS) remains focally more advantageous, even with the delivery of comparable electric field intensity and variability as posterior-anterior tDCS (PA-tDCS) to a cortical region. Thirdly, dose-controlled tDCS does not translate to reduced physiological variability. Together, the work presented here suggests that current flow models are useful for informing dose-controlled protocols and montage comparisons for improved tDCS delivery, however, controlling for anatomical differences in the delivery of electric fields to a target is not sufficient to reduce the variability of tDCS effects in physiology. Thus, the methodology for optimised tDCS delivery remains a subject for further improvement and investigation. Advancements in this field may lead to a trusted methodology assisting stroke survivors with a more effective and efficient motor recovery journey.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Optimising the Application of Transcranial Direct Current Stimulation |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2022. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10143071 |
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