Abstract Details

Title Unraveling How Transcutaneous Afferent Patterned Stimulation Provides Noninvasive Treatment of Refractory Essential Tremor Through Modulation of VIM Thalamus

Topic Movement Disorders

Presentation(s) P1 - Poster Session 1 (11:45 AM-12:45 PM)

Poster/Presentation
Number 5-016

Objective To investigate the neural mechanism of how transcutaneous afferent patterned stimulation (TAPS) improves upper limb essential tremor (ET).

Background ET likely originates from dysfunctional oscillatory activity in the cerebello-thalamo-cortical (CTC) network. Putatively, frequency-calibrated TAPS^TM therapy propagates along afferent wrist nerves and reduces tremors by desynchronizing the ventral intermediate (VIM) thalamus, a hub in the CTC network. However, this is unconfirmed.

Design/Methods In eight prospectively enrolled ET patients (2 female; 65±7 years old), tremor was graded in both upper limbs using the Tremor Research Group Essential Tremor Rating Assessment Scale (TETRAS) before and after 40 minutes of TAPS in the dominant hand. Intraoperatively, local field potentials (LFP) superior to and within the VIM were measured with TAPS ON and OFF. LFP modulation index (MI_LFP) was quantified as the fractional difference of LFP power in the TAPS ON versus OFF conditions. Regression analysis assessed the relationship between MI_LFP and 1) the fractional difference in TETRAS score improvement between the treated and untreated limb; 2) distance from the ventrocaudal VIM.

Results TAPS therapy significantly improved TETRAS scores in the treated limb (0.61; p=0.008) and the untreated limb (0.35; p=0.008). The treated limb further demonstrated a significantly greater TETRAS score improvement than the untreated limb (p=0.047). Regression found that the MI_LFP of the alpha band (8-12 Hz) was preferentially enhanced in patients who had greater relative TETRAS improvement in their treated versus untreated limb (F_(1,52)=15.313, p<0.001), and that alpha band MI_LFP was also most strongly enhanced closest to the ventrocaudal VIM in these patients (F_(1,52)=8.371, p=0.006).

Conclusions This study suggests the underlying mechanism of TAPS involves modulation of alpha band LFP in the ventrocaudal VIM. Future investigation needs to explore the degree to which unilateral therapy leads to a bilateral tremor reduction and broader modulation of the CTC network.

Authors/Disclosures
Cuong P. Luu, Medical Student PRESENTER	Mr. Luu has nothing to disclose.
Youngwon youn, MD	Dr. youn has nothing to disclose.
Jordan N. Ranum	Mr. Ranum has nothing to disclose.
Jennifer Perrault	Miss Perrault has nothing to disclose.
Bryan M. Krause, PhD	The institution of Dr. Krause has received research support from National Institutes of Health.
Matthew I. Banks, PhD	Prof. Banks has received personal compensation in the range of $500-$4,999 for serving as a Consultant for VCENNA, Inc,. The institution of Prof. Banks has received research support from National Institutes of Health. The institution of Prof. Banks has received research support from National Science Foundation.
Laura J. Buyan Dent, MD, PhD (University of Wisconsin)	Dr. Buyan Dent has nothing to disclose.
Kip Ludwig, PhD	Dr. Ludwig has received personal compensation in the range of $500-$4,999 for serving as a Consultant for CVRx. Dr. Ludwig has received personal compensation in the range of $50,000-$99,999 for serving as a Consultant for NeuroOne. Dr. Ludwig has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for NeuraWorx. Dr. Ludwig has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for ONWARD . Dr. Ludwig has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Presidio Medical. Dr. Ludwig has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Restora Medical. Dr. Ludwig has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Abbott. Dr. Ludwig has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Battelle. Dr. Ludwig has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for BlackFynn. Dr. Ludwig has received personal compensation in the range of $50,000-$99,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Neuronoff. Dr. Ludwig has received personal compensation in the range of $50,000-$99,999 for serving on a Scientific Advisory or Data Safety Monitoring board for NeuroOne. Dr. Ludwig has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Presidio Medical. Dr. Ludwig has received personal compensation in the range of $10,000-$49,999 for serving as an officer or member of the Board of Directors for Neuronoff. An immediate family member of Dr. Ludwig has stock in NeuroOne. Dr. Ludwig has stock in NeuraWorx. Dr. Ludwig has stock in Neuronoff. The institution of Dr. Ludwig has received research support from Abbott. The institution of Dr. Ludwig has received research support from Alfred Mann Foundation. The institution of Dr. Ludwig has received research support from LivaNova. The institution of Dr. Ludwig has received research support from Presidio Medical. Dr. Ludwig has received intellectual property interests from a discovery or technology relating to health care.
Wendell Lake	Wendell Lake has nothing to disclose.
Aaron Suminski (University of Wisconsin-Madison)	The institution of Aaron Suminski has received research support from Abbott Neuromodulation.

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