Investigating LFP Correlates of TUS in Patients With Movement Disorders

Not Applicable

Recruiting

• Conditions: Parkinson Disease; Essential Tremor; Dystonia
• Interventions: Device: TUS Sham; Device: TUS Active

• Registration Number: NCT05965960
• Lead Sponsor: University Health Network, Toronto

Brief Summary

Transcranial Ultrasound Stimulation (TUS) is an emerging non-invasive brain stimulation(NIBS) technique that can be used on both superficial and deep brain targets with a high spatial resolution as small as a few cubic millimeters. Neural correlates of TUS have yet been elucidated. To date, no intracranial recordings (i.e., local field potential \[LFP\]) have been captured during or after TUS in patients with movement disorders. In this study, we are aiming to profile basal ganglia LFP activity during and after TUS by using a DBS system that is capable of recording LFP. This can shed light on mechanisms of TUS, as well as allow identification of a neurophysiological biomarker that can be used to tune the TUS sonication parameters for future clinical trials.

Detailed Description

Experiment 1: Subjects will be randomly assigned to either the sham or active stimulation group during the first study visit. In the second study visit, there will be a crossover between the groups, with all subjects undergoing one sham and one active stimulation visit before the study is completed. During the active stimulation visit, a theta burst protocol (Isppa: 30 W/cm2, burst length: 20 ms, period: 200 ms, frequency 500 kHz) will be used to sonicate the bilateral primary motor cortices (M1) or globus pallidus interna (GPi) for 2 minutes. The sham group involves sonications performed with the power set to 0 watts over bilateral M1s/GPis. In both groups, the subjects will be masked using white noise transmitted through earbuds. The targets will be identified anatomically using structural MRIs and a neuronavigation system.

The Percept PC DBS system will be used to record local field potentials (LFPs) from the subthalamic nucleus (STN) or globus pallidus internus (GPI) at various time points: before (baseline) and during the sonications, as well as at 10-, 30-, and 45-minute intervals after the sonications. These recordings will be obtained while the subjects engage in a finger tapping task monitored by an accelerometer, as well as during resting periods. The power of LFPs across different frequencies will be compared and correlated with the velocity observed during the finger tapping task.

Following the completion of sham and active stimulation visits, the subjects will have the opportunity to participate in an optional control group visit, which entails sonication of the occipital cortex utilizing the theta burst protocol.

Experiment 2: TUS will be utilized to target the area directly over the DBS lead, while concurrently recording LFPs to identify any stimulation artifact indicative of target area-sonication engagement.

Study Timeline

• Study Start: 2023-05-18
• Study First Submitted: 2023-06-07
• Status Verified: 2023-07
• Study First Submitted QC: 2023-07-25
• Study First Posted: 2023-07-28
• Last Update Submitted: 2023-10-06
• Last Update Posted: 2023-10-10
• Primary Completion: 2024-06-01
• Study Completion: 2024-06-01

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 25

Inclusion Criteria

1. Adult patients with movement disorders (diagnosed by a movement disorder specialist)
2. Implantation of a Percept PC DBS system at least one month before the sonications
3. Stable dopaminergic medication dose for a minimum of 4 weeks

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Exclusion Criteria

1. Concomitant neurological conditions (stroke, seizure, dementia, major depression / psychiatric disorders, active drug abuse/addiction and major neuromuscular/musculoskeletal diseases)
2. Declined cognitive scores (MoCA score < 22)
3. Implants (cardiac pacemaker, implantable cardioverter-defibrillator, intracranial devices other than DBS system such as shunts and MR-unsafe devices)
4. History of intracranial lesioning procedures
5. Major systemic illness, infection or pregnancy

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Sham Low Intensity Transcranial Focused Ultrasound	TUS Sham	NeuroFUS device stimulation with 4 channel transducer Stimulation target = M1/GPi Stimulation parameters = Theta burst protocol and 0 Watts
Active Low Intensity Transcranial Focused Ultrasound	TUS Active	NeuroFUS device stimulation with 4 channel transducer Stimulation target = M1/GPi Stimulation parameters = Theta burst protocol and 30 Watts

Primary Outcome Measures

Name	Time	Method
LFP power (Experiment 1)	5 minutes long recordings during both study visits at 1) Baseline (20-30 minutes before sonication), 2) during sonication, 3) 10 minutes after sonication, 4) 30 minutes after sonication, and 5) 45 minutes after sonication	The change of power of LFPs across different frequencies
Stimulation artifact (Experiment 2)	Online during sonications	Presence of a stimulation artifact during LFP recordings

Secondary Outcome Measures

Name	Time	Method
Finger tapping task (Experiment 1)	LFPs during finger tapping will be recorded at each visit for half minute at 1) Baseline (20-30 minutes before sonication), 2) 10 minutes after sonication, 3) 30 minutes after sonication, and 4) 45 minutes after sonication	Correlation of LFP power change with the velocity change during finger tapping task as recorded by an accelerometer
Adverse effect profile (Experiment 1 and 2)	From the initiation of the study up to 1 day after its completion.	Presence of adverse effects as reported subjectively by the patient
UPDRS (Experiment 1)	Two assessments will be conducted during each study visit: one at baseline (within the first minute of the study) and the other upon completion of the study visit (between 120 and 130 minutes after the study visit initiation).	Change of UPDRS score

Trial Locations

Locations (1)

Toronto Western Hospital; 🇨🇦 Toronto, Ontario, Canada