Clinical Trial Details
— Status: Active, not recruiting
Administrative data
NCT number |
NCT06232629 |
Other study ID # |
20-5740#4 |
Secondary ID |
|
Status |
Active, not recruiting |
Phase |
N/A
|
First received |
|
Last updated |
|
Start date |
August 1, 2023 |
Est. completion date |
March 30, 2024 |
Study information
Verified date |
January 2024 |
Source |
University Health Network, Toronto |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Interventional
|
Clinical Trial Summary
Transcranial Ultrasound Stimulation (TUS) is an emerging non-invasive brain stimulation
technique capable of targeting both superficial and deep brain areas with high spatial
resolution, down to a few cubic millimeters. In this study, the investigators aim to use TUS
to non-invasively modulate the globus pallidus internus (GPi) in patients with Parkinson's
disease (PD) and dystonia. These patients have previously been implanted with deep brain
stimulation (DBS) leads. The investigators plan to simultaneously record local field
potentials (LFPs) from the DBS leads using the Percept PC device (Medtronic Inc.) while the
DBS is turned off. The study's goal is to investigate the mechanism of action of TUS and its
neuromodulatory effects on LFPs recorded from the GPi. This will enable us to compare the
effects of TUS with those of DBS.
Description:
Study Participants and Visits: The investigators will recruit 10-15 PD and dystonia patients
who have undergone DBS with lead locations at the GPi. These participants will be involved in
three study visits.
First Visit - MRI Scanning: During the first visit, participants will undergo a structural
MRI scan, including T1 and T2 scans, at the Toronto Western Hospital using a 3.0 T Siemens
MR-imager. These scans are crucial for transcranial ultrasound modeling to accurately
localize the targets.
Second and Third Visits - Transcranial Ultrasound Stimulation (TUS): For the second and third
visits, the investigators will use the Brainsight system and BabelBrain, an open source
application, to neuronavigate the TUS transducer (NeuroFUS system). This process involves
sonication of the GPi, with individualized modeling and simulations to account for ultrasound
losses due to variations in skull density and morphology. The investigators will target the
GPi bilaterally (where the DBS electrodes are located) and record local field potentials
(LFPs) before, during, and up to one hour post TUS.
TUS Protocols: Patients will undergo two different TUS protocols across the recording visits,
assigned in random order and spaced at least one week apart. The protocols include:
A tbTUS protocol (5Hz Pulse Repetition Frequency [PRF]), previously shown to increase motor
cortex excitability for about one hour after sonication and a 10Hz protocol, which has been
demonstrated to inhibit motor cortical activity for about one hour post sonication.
Additionally, the investigators will administer two sham-TUS protocols at each visit,
randomly selected to assess placebo effects and the impact of somatosensory stimulation
associated with TUS.
The sham protocols are an active sham-TUS for which the investigators will sonicate the
occipital cortex (Isppa: 30 W/cm2) using either 5 or 10 Hz protocols, and a passive sham-TUS
for which the GPi will be sonicated with either 5 or 10 Hz protocols but at zero power
(Isppa: 0 W/cm2).