The Impact of Transcranial Direct Current Stimulation on the Language Production of Healthy Adults and Individuals With Alzheimer's Disease

Transcranial direct current stimulation (tDCS) is a non-invasive form of brain stimulation that is a technique for modulating cognitive and linguistic functions. Researchers employ tDCS as a way of examining the language system and related memory systems. Although the field is in its infancy, there is evidence to suggest that tDCS applied to language-related brain regions has the potential to exert a beneficial influence on the language and memory functioning of healthy adults as well as individuals with Alzheimer's disease (AD). The purpose of the present review is to critically evaluate the current body of literature on the impact of tDCS on language production in healthy adults and the related memory performance of individuals with AD.

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Transcranial direct current stimulation does not improve memory deficits or alter pathological hallmarks in a rodent model of Alzheimer's disease

Journal of Psychiatric Research ◽

10.1016/j.jpsychires.2019.04.016 ◽

2019 ◽

Vol 114 ◽

pp. 93-98 ◽

Cited By ~ 5

Author(s):

Elise Gondard ◽

Maria Luisa Soto-Montenegro ◽

Amanda Cassol ◽

Andres M. Lozano ◽

Clement Hamani

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Memory Deficits ◽

Rodent Model ◽

Direct Current Stimulation ◽

Model Of Alzheimer’S Disease

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High-Definition Transcranial Direct Current Stimulation Improves Delayed Memory in Alzheimer’s Disease Patients: A Pilot Study Using Computational Modeling to Optimize Electrode Position

Journal of Alzheimer s Disease ◽

10.3233/jad-210378 ◽

2021 ◽

pp. 1-17

Author(s):

Ingrid Daae Rasmussen ◽

Nya Mehnwolo Boayue ◽

Matthias Mittner ◽

Martin Bystad ◽

Ole K. Grnli ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Electric Field ◽

Computational Modeling ◽

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Cortical Atrophy ◽

Brain Anatomy ◽

High Definition ◽

Direct Current Stimulation

Background: The optimal stimulation parameters when using transcranial direct current stimulation (tDCS) to improve memory performance in patients with Alzheimer’s disease (AD) are lacking. In healthy individuals, inter-individual differences in brain anatomy significantly influence current distribution during tDCS, an effect that might be aggravated by variations in cortical atrophy in AD patients. Objective: To measure the effect of individualized HD-tDCS in AD patients. Methods: Nineteen AD patients were randomly assigned to receive active or sham high-definition tDCS (HD-tDCS). Computational modeling of the HD-tDCS-induced electric field in each patient’s brain was analyzed based on magnetic resonance imaging (MRI) scans. The chosen montage provided the highest net anodal electric field in the left dorsolateral prefrontal cortex (DLPFC). An accelerated HD-tDCS design was conducted (2 mA for 3×20 min) on two separate days. Pre- and post-intervention cognitive tests and T1 and T2-weighted MRI and diffusion tensor imaging data at baseline were analyzed. Results: Different montages were optimal for individual patients. The active HD-tDCS group improved significantly in delayed memory and MMSE performance compared to the sham group. Five participants in the active group had higher scores on delayed memory post HD-tDCS, four remained stable and one declined. The active HD-tDCS group had a significant positive correlation between fractional anisotropy in the anterior thalamic radiation and delayed memory score. Conclusion: HD-tDCS significantly improved delayed memory in AD. Our study can be regarded as a proof-of-concept attempt to increase tDCS efficacy. The present findings should be confirmed in larger samples.

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