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Abstract Background Essential tremor (ET) is one of the most common movement disorders of adults, characterized by postural and kinetic tremor. With drug treatment only partially efficient, new treatments are being developed. Objectives The goal of this study was to demonstrate the feasibility of non-thermal focused-ultrasound (FUS) to induce tremor-suppression in an ET rat model. Methods Harmaline-induced tremor rats were treated with FUS along the inferior olivary (IO) system. EMG was recorded continuously during treatment in order to quantify FUS-induced tremor suppression. T2-weighted MRI was performed immediately following treatment and periodically thereafter. Results FUS treatment at an intensity of 27.2 W/cm2 (Isppa) induced significant reduction of tremor in 12 out of 13 ET rats. Tremor frequency was reduced from 6.2 ± 2.8 to 2 ± 1 Hz, p < 0.0003. In 6 of the 12 responding rats, tremor was completely suppressed. Response duration was 70 ± 61s, on average. FUS induced motor response, depicted as movement of the tail and/or the limbs synchronized with the FUS sonication, was also demonstrated both in ET rats and in naïve rats when treated in the medulla oblongata region. Conclusions These results demonstrate the feasibly for obtaining significant tremor reduction or tremor suppression induced by non-thermal, non-invasive, reversible focused-ultrasound. Highlights • Non-thermal focus ultrasound (FUS) was applied to tremoring rats. • Non-thermal focus ultrasound reduced Harmaline-induced tremor in 12/13 rats. • In 6 of the 12 responding rats, tremor was completely suppressed by FUS. • Treatment duration was 52 s whole response duration was 70 ± 61 s on average. • FUS induced motor response synchronized with the FUS sonication. [ABSTRACT FROM AUTHOR]

The goal of this study was to determine the feasibility of focused ultrasound-based neuromodulation affecting auditory evoked potentials (AEPs) in animals. Focused ultrasound-induced suppression of AEPs was performed in 22 rats and 5 pigs: Repetitive sounds were produced, and the induced AEPs were recorded before and repeatedly after FUS treatment of the auditory pathway. All treated animals exhibited a decrease in AEP amplitude post-treatment in contrast to animals undergoing the sham treatment. Suppression was weaker for rats treated at 2.3 W/cm2 (amplitudes decreased to 59.8 ± 3.3% of baseline) than rats treated at 4.6 W/cm2 (36.9 ± 7.5%, p <0.001). Amplitudes of the treated pigs decreased to 27.7 ± 5.9% of baseline. This effect lasted between 30 min and 1 mo in most treated animals. No evidence of heating during treatment or later brain damage/edema was observed. These results demonstrate the feasibility of inducing significant neuromodulation with non-thermal, non-invasive, reversible focused ultrasound. The long recovery times may have clinical implications. [ABSTRACT FROM AUTHOR]