Transcranial Direct Current Stimulation (tDCS) Dose Response: Lecture by Marom Bikson

Detailed slides can be downloaded here www.neuralengr...
And the core paper references can be downloaded here www.neuralengr...
Abstract from core paper:
Background: Transcranial direct current stimulation (tDCS) is investigated to modulate neuronal function by applying a fixed low-intensity direct current to scalp. Objectives: We critically discuss evidence for a monotonic response in effect size with increasing current intensity, with a specific focus on a question if increasing applied current enhance the efficacy of tDCS. Methods: We analyzed tDCS intensity does-response from different perspectives including biophysical modeling, animal modeling, human neurophysiology, neuroimaging and behavioral/clinical measures. Further, we discuss approaches to design dose-response trials. Results: Physical models predict electric field in the brain increases with applied tDCS intensity. Data from animal studies are lacking since a range of relevant low-intensities is rarely tested. Results from imaging studies are ambiguous while human neurophysiology, including using transcranial magnetic stimulation (TMS) as a probe, suggests a complex state-dependent non-monotonic dose response. The diffusivity of brain current flow produced by conventional tDCS montages complicates this analysis, with relatively few studies on focal High Definition (HD)-tDCS. In behavioral and clinical trials, only a limited range of intensities (1-2 mA), and typically just one intensity, are conventionally tested; moreover, outcomes are subject brain-state dependent. Measurements and models of current flow show that for the same applied current, substantial differences in brain current occur across individuals. Trials are thus subject to inter-individual differences that complicate consideration of population-level dose response. Conclusion: The presence or absence of simple dose response does not impact how efficacious a given tDCS dose is for a given indication. Understanding dose-response in human applications of tDCS is needed for protocol optimization including individualized dose to reduce outcome variability, which requires intelligent design of dose-response studies.

[@huiwang1726]

Many people want to know how long the tDCS can solve their problem, This lecture is useful.

[@JonCammarata]

Volts per Meter? Current per area is definitely an important factor in tdcs. But, V/m makes no sense.

[@MaromBikson]

It is a subtle but important idea. We control the applied voltage or the applied current. This is a single number if we talk about peak stimulation intensity,
INSIDE the tissue we produce a current density (A/m2) or equivalently an electric field (V/M). Because the current density and electric field vary across different parts of the body, there is no *single* current current or electric field across the entire body. There is therefore a *distribution* across the body. There is a single current density or electric field if we focus on just one tissue area.
See these slides if they help static1.squarespace.com/static/5cd3231cd7819e6ae55fedb4/t/63bf12769d51a072a5f419c9/1673466494836/2023_NANS_Bikson_Marom_Lecture1_EngineeringPrinciples_Final2a.pdf

[@LivingisGiving]

terrible audio

[@healingvalleyphysiotherapy8268]

👍

[@-m7k0z7-9]

Have you tasted this on frontal lobe mTBI patients?

[@martinlutherkingjr.5582]

Tastes like chicken