Safety and neuromodulation effect of transcranial focused ultrasound for motor recovery in patients with subacute stroke
Meng-Ting Lin, Shao-Yu Chen, Pin-Hua Lai, Yan-Ci Liu, Wen-Shiang Chen, Po-Chun Chu, Hao-Li Liu, Bo-Ching Lee, Shu-Mei Yang, Chueh-Hung Wu, Ting-Ju Lai, Abel Po-Hao Huang, Ming-Yen Hsiao
Journal of NeuroEngineering and Rehabilitation 2026 · 10.1186/s12984-026-01945-4
Abstract
Introduction Transcranial focused ultrasound (tFUS), a non-invasive brain neuromodulation, can target deeper and more precise brain regions compared to transcranial magnetic stimulation. However, its safety, neuromodulation and therapeutic effects in subacute stroke patients remain unclear. Therefore, the aim of this project is to demonstrate the safety and preliminary efficacy of tFUS for upper limb motor recovery in subacute stroke patients. Methods In this phase I single-arm study, we recruited 10 patients with subacute (≤ 3 months) unilateral stroke. tFUS was applied to the contralesional M1 by neuronavigation once daily for five sessions, using I SPTA 2.8 W/cm² in free field (estimated in situ Conclusion tFUS was safe and well tolerated in subacute stroke patients, with only minor transient AEs and no evidence of structural or neuropsychological harm. tFUS demonstrated potential to enhance upper limb motor recovery and functional outcomes. Although exploratory analyses suggested trends toward cortical excitability changes, these findings were not statistically significant and require confirmation in larger controlled trials.
Abstract via europepmc.
Exposures
Exposure 1: tFUS to contralesional M1, five daily sessions
Target: primary motor cortex — “contralesional M1 upper-limb area”
Device: other named manufacturer · NaviFUS Corporation · NaviFUS 001 (256-element phased array) ✓
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 500 | ✓✓✓ |
| Pulse duration (ms) | not reportedimplied by duty cycle ÷ PRF: 3 ms (not stated by the paper) | ⚑ |
| Pulse repetition frequency (Hz) | 100 | ✓✓✓ |
| Duty cycle (%) | 30 | ✓✓✓ |
| Sonication duration (s) | 600 | ✓✓✓⚑ |
| Free-field pressure (kPa) | 530 | ✓✓✓⚑ |
|---|---|---|
| Free-field Isppa (W/cm²) | 9.33 | ✓✓✓ |
| Free-field Ispta (W/cm²) | 2.8 | ✓✓✓ |
| In-situ estimate | simulationmean or range across subjects | |
| In-situ pressure (kPa) | not reported | |
| In-situ Isppa (W/cm²) | not reported | |
| In-situ Ispta (W/cm²) | 0.084, 0.199swept | ✓✓✓⚑ |
PRF 100 Hz, duty cycle 30%, total exposure time 10 min per session, once daily for five consecutive sessions; no pulse duration stated.
Flags from extraction
exposures[0].target.label— Text says the transducer was positioned over the ipsilesional motor cortex hotspot, but the targeting statement and results say contralesional (healthy) M1; contralesional recorded.exposures[0].timing.sonication_duration_s— Paper gives 'total exposure time 10 min' per session; whether this was one uninterrupted train is not stated; recorded as 600 s.exposures[0].free_field.pressure_kpa— Converted from 0.53 MPa.exposures[0].in_situ.ispta_w_cm2— Per-participant estimated in situ ISPTA range from skull-CT based simulation (Table 2); the abstract says <0.3 W/cm2.exposures[0].timing.pulse_duration_ms— Pulse duration not stated; left not_reported.randomised— Single-arm study; the rTMS comparison group was retrospective and matched, not randomised.