Abstract Details

Title Treating word finding difficulty in multiple sclerosis using high-definition transcranial direct current stimulation targeting the pre-Supplementary Motor Area

Topic Neuro-rehabilitation

Presentation(s) P18 - Poster Session 18 (5:30 PM-6:30 PM)

Poster/Presentation
Number 7-003

Background

Word finding difficulty is prevalent in PwMS and can impact communication, job performance, and quality of life. Effective treatments that target underlying mechanisms are lacking. The pre-SMA is central to word finding and has recently been a target site for electromodulation to treat word finding difficulty. This intervention has yet to be examined in MS.

Objective

We examined the therapeutic effects on word finding difficulty in persons with multiple sclerosis (PwMS) using high-definition transcranial direct current stimulation (HD-tDCS) targeting the pre-Supplementary Motor Area (pre-SMA).

Design/Methods In an open-label study, PwMS (N=7, mean age 52.4 years, 6 women) underwent ten 20-minute sessions of active 1 mA anodal pre-SMA HD-tDCS. Neuropsychological assessment that included verbal retrieval measures (e.g., letter and category fluency, color-word interference naming test, Boston naming) and task-based electroencephalography (EEG) were administered at baseline, immediately after and one month after completion of intervention. We used paired t tests comparing post-intervention time points to baseline to determine if verbal retrieval performance and EEG power/phase coherence had significant change after intervention.

Results There was improvement in category fluency (immediate p = 0.066), color-word interference - inhibition (immediate and one month, p = 0.066 and 0.063, respectively) and -inhibition/switch (one month, p = 0.045), while no difference in letter fluency or Boston naming. There was increase in EEG theta and delta event-related power as well as theta phase coherence immediately post-intervention, suggesting improved neuronal synchronization. Notably, frontal theta power change showed a marginally significant correlation with change in color-word inhibition (Pearson’s r = 0.862, p = 0.06), suggesting a predictive role of EEG marker on behavioral response.

Conclusions

HD-tDCS represents one novel neurorehabilitation strategy to modulate the pre-SMA for MS-related word finding difficulty. This effect is potentially mediated by increased neuronal synchronization as measured by EEG.

Authors/Disclosures
Hsueh-Sheng Chiang, MD, PhD (University of Texas Southwestern Medical Center) PRESENTER	The institution of Dr. Chiang has received research support from NIH/NIDCD. The institution of Dr. Chiang has received research support from Texas Alzheimer's Research and Care Consortium.
	No disclosure on file
	No disclosure on file
	No disclosure on file
John Hart, MD (The University of Texas At Dallas)	The institution of Dr. Hart has received research support from Department of Defense.