Ultrasound Neuromodulation in Essential Tremor
University of California, San Francisco
Summary
This study is being done to test whether low-intensity focused ultrasound (LIFU) (low energy sound waves) cause temporary changes in brain activity and behavior when directed at particular parts of the brain. By targeting LIFU to the parts of the brain thought to be responsible for essential tremor (ET), and measuring any associated improvement in tremor, the investigators hope to show that LIFU can be a useful tool for studying the brain circuits responsible for tremor and other brain disorders.
Description
Hypothesis Precisely targeted low-intensity focused ultrasound (LIFU) modulation of the dentatorubrothalamic tract (DRTT) results in transient improvement of essential tremor (ET). DRTT LIFU neuromodulation produces functional connectivity changes that mirror brain network changes after MR-guided high-intensity focused ultrasound (HIFU) thalamotomy. Aims 1. To determine the optimal stimulation parameters for DRTT LIFU neuromodulation: the investigators will record wrist accelerometer signals while systematically varying pulse repetition frequency, duty cycle, and acoustic intensity. 2. To m…
Eligibility
- Age range
- 18+ years
- Sex
- All
- Healthy volunteers
- No
Inclusion Criteria: * Patients with medically refractory tremor scheduled to undergo MR-guided high-intensity focused ultrasound (HIFU) thalamotomy to treat their tremor at UCSF. Exclusion Criteria: * Due to the logistical complexity of performing MRI in patients with MR-conditional pacemakers (need for device and patient monitoring), patients with pacemakers will be excluded from enrollment. All other patients undergoing HIFU thalamotomy for tremor will be eligible for enrollment.
Interventions
- DeviceFocused Ultrasound Neuromodulation - Sham Control
Each ultrasound stimulation protocol will last for 60 seconds, consisting of 4 pulse trains of 5 seconds duration separated by 10 second intervals without stimulation. Across successive stimulation protocols (up to 25/patient) investigators will systematically vary pulse repetition frequency, duty cycle, and acoustic intensity to determine how these parameters contribute to the behavioral effect (transient tremor reduction). Parameters will be shuffled to control for group-level carry over effects. A defocusing lens will be in place during the session to test the difference between focused and unfoucused ultrasound while controlling for non-specific auditory and somatosensory confounds.
- DeviceFocused ultrasound neuromodulation
Each ultrasound stimulation protocol will last for 60 seconds, consisting of 4 pulse trains of 5 seconds duration separated by 10 second intervals without stimulation. Across successive stimulation protocols (up to 25/patient) investigators will systematically vary pulse repetition frequency, duty cycle, and acoustic intensity to determine how these parameters contribute to the behavioral effect (transient tremor reduction) in each patient. Parameters will be shuffled to control for group-level carry over effects and will include sham (unfocused or off-target stimulation) conditions to control for non-specific auditory confounds.
Location
- Pritzker Building, UCSFSan Francisco, California