Feasibility Study on the Application of Transcranial Focused Ultrasound Stimulation in Ischemic Stroke Rehabilitation

JeYoung Jung, Minjae Cho, Sekwang Lee, Hyun-Joon Yoo, Matthew A. Lambon Ralph, Sung-Bom Pyun

2024 · 10.1101/2024.11.13.24317114

human patientstrokeclinical scale

Abstract

Stroke is a leading cause of long-term neurological disability and death worldwide. Traditional neurorehabilitation methods result in full recovery for less than 15% of stroke patients, highlighting the need for innovative approaches. Low-intensity transcranial focused ultrasound stimulation (tFUS) has emerged as a promising non-invasive neuromodulation technique with high focality and deep tissue penetration. This study evaluates the feasibility, safety and efficacy of tFUS for motor rehabilitation in ischemic stroke patients. We conducted a single-group prospective pilot study involving two stroke patients who received tFUS targeting the motor cortex contralateral to the lesion site three times a week. Patients were evaluated using multiple clinical measures of motor function. Both patients showed improvements in the Fugl-Meyer Assessment upper extremity score, kinesthetic sensation, stereognosis score from the Nottingham Sensory Assessment, and the Modified Barthel Index score. Follow-up evaluations immediately and three weeks after stimulation indicated sustained motor function improvements. The results suggest that tFUS can effectively enhance motor recovery in stroke patients without adverse events. This study provides robust evidence supporting the potential of tFUS in stroke rehabilitation, opening new avenues for clinical application and research.

Abstract via europepmc.

Specieshuman

Subjects2 participants

Sessions per subjectnot reported

Randomisedno

Blindingnot reported

Sham / controlnone

Auditory controlnot reported

Readout timingoffline

Anaesthesianot applicable

Readoutsclinical scale — Fugl-Meyer Assessment; Nottingham Sensory Assessment; Modified Barthel Index; Berg Balance Scale; Box and Block; ARAT; finger grip

Direction of effectmixed or unclearBoth patients improved on FMA upper extremity, kinaesthetic sensation, stereognosis and MBI after contralesional M1 stimulation intended to be inhibitory; single-group pilot with no control.

Adverse eventsnone observedAdverse event evaluations (stroke exacerbation, seizure, headache, neurological symptoms) at each session and at 3 weeks; no adverse event in either participant.

Exposures

Exposure 1: tFUS to contralesional M1 hand knob

Target: primary motor cortex — “central sulcus 'knob' area within the primary motor cortex (M1) contralateral to the lesion site”
Device: Neurosona · Neurosona Co., Ltd. · NS-US200 with E40 transducer ✓

Pulse timing
Waveform	pulsed
Fundamental frequency (kHz)	250	✓✓✓
Pulse duration (ms)	0.5	✓✓✓
Pulse repetition frequency (Hz)	100	✓✓✓
Duty cycle (%)	5pulse duration × PRF gives 5%	✓✓✓
Sonication duration (s)	1,200	✓✓✓

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)	not reported
In-situ Ispta (W/cm²)	not reported
Isppa, domain unspecified (W/cm²)	3	✓✓✓⚑
Ispta, domain unspecified (W/cm²)	1.5	✓✓✓⚑

Protocol, in the paper’s words

Treatment given three times a week; total treatment duration 1200 seconds without a sonication interval (20 minutes).

Flags from extraction

exposures[0].unspecified_domain.isppa_w_cm2 — 'Acoustic intensity at focus (AIF) 3 W/cm2' given with no domain; recorded as Isppa on that reading.
exposures[0].unspecified_domain.ispta_w_cm2 — Ispta symbol is missing in the text ('(I )'); read as spatial peak temporal-average intensity per the preceding words. Paper also states in situ MI 0.6.
n_sessions_per_subject — Three sessions per week; total number of sessions not stated.
blinding — Single-group pilot; blinding not stated.