Neurophysiological and Clinical Effects of Low-intensity Transcranial Ultrasound of the Motor Cortex in Parkinson’s Disease (P4-11.014)

Abstract

<h3>Objective:</h3> Evaluate the neurophysiological and clinical effects of transcranial ultrasound stimulation (TUS) of motor cortex (M1) in PD patients. <h3>Background:</h3> Low-intensity TUS is a non-invasive brain stimulation technique that can reduce cortical excitability during sonication (online effect). TUS in a theta burst (tb) mode (tbTUS) can increase cortical excitability (offline or plasticity effect). PD have altered cortical excitability, and benefit from non-invasive stimulation of M1. <h3>Design/Methods:</h3> Eleven PD patients (2F, age 60.7±7.7 [mean±SD] years) were evaluated in ON and OFF dopaminergic medication states, and 16 controls (6F, age 65.6±10 years). The online protocol consisted of M1 TUS of 20W (active) and 0W (sham), with simultaneous transcranial magnetic stimulation measures of motor-evoked potential (MEP) amplitude. The offline protocol was 80 seconds of M1 tbTUS at 20W contralateral to the more affected side. MEP was recorded at baseline (before tbTUS), at 5-minutes (T5), T30, and T60 after tbTUS. Motor (m)UPDRS was evaluated in PD at baseline and at T60. <h3>Results:</h3> Online TUS did not reduced MEP amplitudes. For offline effects, a linear mixed model on MEP amplitudes showed a significant effect of time (F=2.8, p=0.046) and trend for time x group interaction (F=2.23, p=0.092) comparing PD-OFF and controls. There was a significant effect of time (F=4.17; p=0.009) but not group comparing PD-ON and controls. There was a trend for an effect of group (F=3.47; p=0.069) comparing MEP ratios for PD-ON and PD-OFF. The mUPDRS was significantly reduced at T60 (ON 24.1 ± 2.1; OFF 29.3 ± 1.7 [mean ± SE]) compared to baseline (ON 29.5 ± 2.3; OFF 30.8 ± 62.0 (paired t-test, ON p=0.004, OFF p=0.064) in PD-ON group. <h3>Conclusions:</h3> Increased M1 excitability following tbTUS also occurs in older controls and PD-ON, but not in PD-OFF. The mUPDRS reduction indicate a possible clinical effect in PD-ON. The study is ongoing, and more subjects are being recruited. <b>Disclosure:</b> Dr. Grippe has nothing to disclose. Mr. Shamli Oghli has nothing to disclose. Dr. SARICA has nothing to disclose. Miss Rinchon has nothing to disclose. Dr. Nankoo has nothing to disclose. Dr. Chen has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Abbvie. Dr. Chen has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Merz. Dr. Chen has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Paladin Labs. Dr. Chen has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Ipsen. Dr. Chen has received personal compensation in the range of $10,000-$49,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Canadian Journal of Neurological Sciences. Dr. Chen has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Movement Disorders. The institution of Dr. Chen has received research support from Canadian Institutes of Health Research. The institution of Dr. Chen has received research support from NIH. The institution of Dr. Chen has received research support from Natural Science and Engineering Research Council of Canada. Dr. Chen has received research support from Parkinson Foundation. The institution of Dr. Chen has received research support from National Organization for Rare Disease. The institution of Dr. Chen has received research support from Merz.