Unlocking the Potential: How tDCS and AD Risk Factors Impact White Matter Microstructure Integrity

Published on September 1, 2023

Imagine you’re a treasure hunter exploring a cave. You know that the cave is filled with precious gems, but you’re not sure how to find them. So, you decide to use a special lantern (transcranial direct current stimulation, or tDCS) to guide your way. As you navigate deeper into the cave, you make some interesting discoveries. Certain factors, like the type of lantern you use (APOE ε4 carrier status) and whether you’re a male or female, can affect the brightness of the light (increased fractional anisotropy in the right uncinate fasciculus). You also learn that combining these factors can have an even more significant impact on the luminosity of the lantern (more pronounced increase in FA values in APOE ε4 carriers and females with Val66 homozygotes in the right uncinate fasciculus). Furthermore, you find that the number of sparkling gems (changes in the score for delayed memory) is influenced by the presence of another treasure (baseline Aβ deposition), which is positively associated with differences in another part of the cave (FA of the left cingulum in the hippocampal area), known for its memory-enhancing properties. With this newfound knowledge, you recognize the importance of precision in your treasure-hunting method (precision medicine-based therapeutic approaches) for unlocking hidden gems (prodromal stages of Alzheimer’s disease). There is still more to uncover, so grab your mining gear and explore our research!

Background: Little research exists on how individual risk factors for Alzheimer’s disease (AD) affect the intermediate phenotype after transcranial direct current stimulation (tDCS), despite the importance of precision medicine-based therapeutic approaches.Objective: To determine how an application of sequential tDCS (2 mA/day, left dorsolateral prefrontal cortex, 10 sessions) affects changes in white matter (WM) microstructure integrity in 63 mild cognitive impairment (MCI) patients with effect modifiers such as Aβ deposition, APOE ε4 carrier status, BDNF Val66Met polymorphism status, and sex.We examined individual effect modifier-by-tDCS interactions and multiple effect modifiers-by-tDCS interactions for diffusion metrics. We also evaluated the association between baseline Aβ deposition and changes in WM microstructure integrity following tDCS.We found that APOE ε4 carrier status and sex had a significant interaction with tDCS, resulting in increased fractional anisotropy (FA) in the right uncinate fasciculus (UF) after stimulation. Additionally, we observed multiple effect modifiers-by-tDCS interactions on WM integrity of the right UF, leading to a more pronounced increase in FA values in APOE ε4 carriers and females with Val66 homozygotes. Finally, baseline Aβ deposition was positively associated with a difference in FA of the left cingulum in the hippocampal area, which showed a positive association with the changes in the score for delayed memory.Our study shows the differential impact of individual AD risk factors on changes in the early intermediate phenotype after sequential tDCS in MCI patients. This research emphasizes the importance of precision medicine approaches in tDCS for the prodromal stages of AD.

Read Full Article (External Site)

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes:

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>