The purpose of this research study is to find out the optimal intensity and frequency of Low Intensity Focused Ultrasound (LIFU) that is safe and tolerable in people who have had a stroke.
Aim 1 is to determine the optimal intensity of Low Intensity Focused Ultrasound stimulation (LIFUS) in stroke patients in terms of safety. We will investigate the optimal spatial-peak temporal-average intensity/ISPTA in the range of 0(or sham) W/cm2 to 8 W/cm2. Safety will be investigated by assessing clinically detectable signs and symptoms by monitoring vital signs and surveying subjects with a questionnaire before and after each stimulation session, and additionally by detecting subclinical neuronal injury using MRI/DWI. Aim 1 requires up to 36 subjects. Aim 2 is to determine the optimal frequency of LIFU stimulation in stroke patients in terms of cortical excitability. Stroke subjects undergo each of the 5 frequency levels (0.35 MHz; 0.5 MHz; 0.75 MHz, 1.0 MHz and 1.5 MHz) on 5 different days with at least one day washout. The intensity (ISPTA) will set up at the level that is determined from Aim 1. Cortical excitability is measured by the amplitude of motor evoked potentials (MEPs) induced by Transcranial Magnetic Stimulation (TMS) from the Abductor Pollicis Brevis (ABP) muscle of the affected side. MEPs will be recorded pre- and post-stimulation to determine the optimal intensity for maximal cortical excitability from the hemisphere where the lesion is located. Aim 2 requires 18 subjects.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
OTHER
Masking
NONE
Enrollment
18
Brain stimulation using ultrasonic stimulation in a sequence of increasing intensity (sham, 1 W/CM2, 2 W/CM2, 4 W/CM2, 6 W/CM2, 8 W/CM2)
Brain stimulation using ultrasonic stimulation of intensity level determined from intervention 1 at progressively increasing frequency levels (0.35 MHz; 0.5 MHz; 0.75 MHz, 1.0 MHz and 1.5 MHz)
Duke University Hospital
Durham, North Carolina, United States
Safety Outcomes as Measured by the Number of Participants With a "Major Response"
A "major response" is pre-defined as having any of the following events: Second degree scalp burn; Clinical seizure; New lesion on DWI sequence of MRI scan and the lesion not explained by any other cause(s) or decreased ADC under the transducer stimulating motor cortex area; Patient discontinues from the study due to any reason.
Time frame: At any point during or immediately following intervention on day of LIFUS application
Cortical Excitability as Measured by the Number of Participants Who Improved by ≥ 20% on Motor Evoked Potential (MEP) Amplitude
Cortical excitability is measured by Motor evoked potential(MEP) amplitude using Transcranial Magnetic Stimulation. The median amplitude of all MEPs was calculated and used as the measure of the corticospinal excitability. The percentage change in MEP (post-pre) was calculated and the number of participants who improved by ≥20 % on MEP amplitude is reported.
Time frame: Immediately after ultrasonic stimulation
Motor Sequence Learning (MSL) as Measured by the Number of Participants Who Improved by ≥ 20% on a MSL Task
MSL improvements is quantified by calculating the percentage change in the median response time (post-pre) and the number of participants who improved by ≥20 % on MSL is reported.
Time frame: Immediately after ultrasonic stimulation
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