Neuroscientists Produce Guide for Ultrasound

Photo: Brain

Status epilepticus is a condition in which the brain is in a state of persistent seizure and which, if not halted, can lead to Sudden Unexplained Death in Epilepsy (SUDEP). But, as the recent article by Tyler and colleagues shows, ultrasonic neuromodulation does not necessarily need to be focused to attenuate epileptic seizures, meaning that it can be quickly applied in neurocritical care situations.

Ultrasound is an acoustic wave occurring at frequencies exceeding the range of human hearing. Uses range from food processing to communication and include medical imaging. Professor William Tyler and his research group have spent several years developing noninvasive methods for brain stimulation employing low-intensity, low-frequency (LILFU) ultrasound. "Much of our time had been spent on understanding the biological effects of LILFU on intact brain circuits and how to control neural activity using LILFU," Tyler said.

The team has observed that the mechanical bioeffects of ultrasound are indeed capable of stimulating neuronal activity, meaning that ultrasound could join other therapies for neurological disorders — namely, implanted electrodes, such as those used in deep-brain stimulation, and external magnetic stimulators used for transcranial magnetic stimulation to treat disorders such as Parkinson's disease, major depression, and dystonia. The major advantage of using ultrasound for brain stimulation is that it can confer spatial resolution at millimeter precision while being focused through the skull to deep-brain regions without the need for invasive brain surgery, Tyler said.

"We have also shown that ultrasound can be used to stimulate synaptic transmission between groups of neurons within the brain in a manner similar to conventional implanted stimulating electrodes without generating significant heating of the brain tissue," said Tyler.

Moving this technology forward will require scientists, engineers, and physicians spanning many disciplines. "There is a major need for increased open communication among engineers designing ultrasound-based medical devices, neuroscientists studying the core biological effects of ultrasound, and clinicians implementing ultrasound for therapeutic interventions," said Tyler.; Source: Virginia Tech