An interventional study of LIFUS: Active 5 Hz Theta Burst and LIFUS: Active 10 Hz in Parkinson Disease (PD), sponsored by University Health Network, Toronto. Recruiting at 1 site in Canada. Open to participants aged 18 Years to 90 Years. Per ClinicalTrials.gov, last updated 2026-09-29.
Sponsored by University Health Network, Toronto · Not applicable, Interventional, and Basic science
Low intensity focused ultrasound (LIFUS) is a novel non-invasive brain stimulation (NIBS) technique that permits stimulation with high spatial focality and can reach greater depth compared other methods. This study will look at the effects of two different LIFUS stimulations on task performance in patients with Parkinson's disease. The effects of real stimulation will also be compared to sham stimulation. The evaluations will include behavioral tasks on the computer, the Unified Parkinson's Disease Rating Scale (UPDRS) motor scoring, and finger accelerometry recordings. These will be done before the LIFUS simulations and repeated after. This is to evaluate the different mechanisms and efficacy of these stimulations on deep brain areas.
The goal of this study is to evaluate the effects of two different deep brain LIFUS protocols on task performance in PD patients. We will use two different protocols (5 Hz theta Burst vs 10 Hz inhibitory), bilaterally on the GPi of PD patients in two different sessions and evaluate their performance in visuomotor tasks using stop signal paradigm. We will also use active sham in a separate session bilaterally on the occipital cortex, more specifically Brodmann area 19 to compare differences in tremor activity. We will record behavioral performance of the patients to disentangle effects of different TUS protocols on PD patients. We will also use finger accelerometer on the tremor dominant hand, to evaluate possible changes in tremor.
For each participant, there will be four visits. In the first visit, a structural MRI scan will be obtained. In the subsequent three visits, the LIFUS experiments including the behavioral tasks on the computer, UPDRS motor scoring, and finger accelerometry recordings will be conducted in random order. In these visits, the task performance (stop-signal task) will be recorded before and after applying the 3 different LIFUS paradigms: 1) theta burst TUS of the GPi in one session, 2) 10Hz TUS of the GPi in one session, and 3) active sham condition in the occipital cortex (bilateral) where we will use theta burst LIFUS to the Brodmann area 19 at a TPO distance of \~30mm. Visits 2, 3, and 4 will be separated by at least 1 week each and theta burst TUS (2 minutes x2 =4 min), 10 Hz protocol (Burst length 30ms, period 1000, 30% dc. Total Time: 40 seconds x2= 80 seconds) and sham theta bust TUS will be tested in random order.
Exclusion Criteria:
3 different LIFUS paradigms in random order: 1) theta burst TUS of the GPi in one session, 2) 10Hz TUS of the GPi in one session, and 3) active sham condition in the occipital cortex (bilateral) where we will use theta burst LIFUS to the Brodmann area 19 at a TPO distance of \~30mm.
Device: LIFUS: Active 5 Hz Theta Burst · Device: LIFUS: Active 10 Hz · Device: LIFUS: Sham
LIFUS 5 Hz theta burst bilaterally on the GPi
LIFUS 10 Hz bilaterally on the GPi
Sham: LIFUS theta burst to occipital lobe
Stop-Signal Task
Time frame: Visits 2-4: before stimulation, 20 minutes post round 1 of stimulation, and 25 minutes post round 2 of stimulation
Unified Parkinsons Disease Rating Scale (UPDRS)
Part III - Motor Assessment
Time frame: Visits 2-4: At the beginning of the visit, and at the end of the visit after all stimulation. Visits 2-4 will take place over at least 3 weeks as each visit is at least 1 week apart.
Rest Tremor
Resting tremor will be measured by an accelerometer
Time frame: Visits 2-4: resting tremor will be recorded by an accelerometer periodically during each visit. This will be over at least 3 weeks, since each visit is at least 1 week apart.
Postural Tremor
Postural tremor will be measured as arms are outstretched using an accelerometer
Time frame: Visit 2 - 4. At each visit, it will be recorded twice. Once before the stimulation and another after. This will take place over at least 3 weeks, since each visit is at least 1 week apart.
Plan to share: No
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University Health Network, Toronto