Transcranial focused ultrasound for the treatment of tremor: A preliminary case series

C.M. Deveney, J.R. Surya, J.M. Haroon, K.D. Mahdavi, K.R. Hoffman, K.C. Enemuo, K.G. Jordan, S.A. Becerra, T. Kuhn, A. Bystritsky, S.E. Jordan

Brain Stimulation 2024, 17, 35-38 · 10.1016/j.brs.2023.12.007

human patientessential tremorclinical scale

Abstract

Background Essential tremor (ET) can be debilitating. Treatments for ET include beta-blockers and surgical interventions. Low-intensity focused ultrasound (LIFU) may offer an office-based non-invasive alternative. Objective This pilot open label clinical trial explores safety, feasibility, and potential efficacy of LIFU in treatment of ET. Methods We report outcomes from the first 10 participants in this IRB-approved trial of LIFU for treatment of ET. The ventral intermediate nucleus of the thalamus (Vim) was targeted using structural and functional MRI. Participants underwent eight 10-min sessions of LIFU targeting the contralateral (Vim) to the most affected hand. Safety was closely monitored; Global Rating of Change (GRC) and The Essential Tremor Rating Scale (TETRAS) scores were collected. Results No adverse effects were reported. Eight participants reported a GRC ≥2. TETRAS performance subscale demonstrated clinically significant improvement in all participants. Conclusion Preliminary findings support LIFU's safety and feasibility. The potential efficacy encourages additional sham-controlled studies.

Abstract via europepmc.

Specieshuman

Subjects10 participants

Sessions per subject8

Randomisedno

Blindingnone

Sham / controlnone

Auditory controlnot reported

Readout timingoffline

Anaesthesianot applicable

Readoutsclinical scale — Essential Tremor Rating Assessment Scale (TETRAS: ADL and Performance subscales); Global Rating of Change (GRC)

Direction of effectnot assessedStudy assessed clinical tremor severity (TETRAS) and global rating of change, not neurophysiological excitation/inhibition; TETRAS scores decreased (improved) in all 10 patients.

Adverse eventsnone observedNo adverse events or serious adverse events were reported.

Exposures

Exposure 1: Vim LIFU for essential tremor

Target: ventral intermediate nucleus — “ventral intermediate nucleus of the thalamus (Vim)”
Device: BrainSonix · Brainsonix · Pulsar 1002 ✓

Pulse timing
Waveform	pulsed
Fundamental frequency (kHz)	650	✓✓✓
Pulse duration (ms)	5	✓✓✓
Pulse repetition frequency (Hz)	10	✓✓✓
Duty cycle (%)	5pulse duration × PRF gives 5%	✓✓✓
Sonication duration (s)	30	✓✓✓

Pressure and intensity, by domain
Free-field pressure (kPa)	not reported
Free-field Isppa (W/cm²)	not reported
Free-field Ispta (W/cm²)	not reported
In-situ estimate	not reported
In-situ pressure (kPa)	not reported
In-situ Isppa (W/cm²)	14.39	✓✓✓
In-situ Ispta (W/cm²)	0.72	✓✓✓
Pressure, domain unspecified (kPa)	610	✓✓✓

Protocol, in the paper’s words

Participants underwent eight, 10-min focused ultrasound sessions, prescribed to be completed over the course of one week. LIFU was administered 30 s on and 30 s off for 10 min as described in Refs. [19,20].

Flags from extraction

exposures[0].free_field — Domain of the reported pressure/intensity values (water vs in-brain) is not stated by the paper; recorded as unspecified_domain.
direction_of_effect — Paper reports only clinical tremor scales (TETRAS, GRC), no neurophysiological measure of excitation/inhibition, so direction could not be assessed.
randomised — Open-label single-arm design; paper does not use the word randomised, inferred false.