Neuroscientists prove ultrasound can be tweaked to stimulate different sensations

Thu, 12/06/2012 - 2:26pm



"Ideally, neurologists should be able to tailor treatments to the specific sensations their patients are feeling," said William "Jamie" Tyler, an assistant professor at the Virginia Tech Carilion Research Institute, who led the study published this week in PLOS ONE. "Unfortunately, even with today's technologies, it's difficult to stimulate certain types of sensations without evoking others. Pulsed ultrasound allows us to selectively activate functional subsets of nerve fibers so we can study what happens when you stimulate, for example, only the peripheral fibers and central nervous system pathways that convey the sensation of fast, sharp pain or only those that convey the sensation of slow, dull, throbbing pain."


"Neuropathy involves both motor nerves that control how muscles move and sensory nerves that receive sensations such as heat, pain, and touch," Tyler said. "So clinicians may use, for example, small resonator devices to vibrate the skin or lasers to heat the surface of the skin. But we wanted to develop a method that could activate superficial and deep mechanical receptors, thermal receptors, and even combinations of both. So we used pulsed ultrasound."



Tyler believes the finding has important implications for pain diagnosis.

"Current methods of diagnosing and characterizing pain can sometimes seem archaic," Tyler said. "To measure pain through mechanical stimulation, for example, physicians might touch the skin with nylon monofilaments known as von Frey hairs, or they'll stroke the skin with a paintbrush. For thermal sensory testing, patients may even plunge their hands into ice water until the pain becomes too great. We're hoping to provide physicians with more precise diagnostic tools."


"By combining pulsed ultrasound with the technologies to record brain activity, Jamie Tyler and his colleagues are taking this to a whole new level of diagnostics," Friedlander said. "And the diagnostics will ultimately drive the therapeutics. This research is a great example of how new technologies can be adapted for real-world, patient-centered diagnoses and treatments."

Tyler noted the discovery could lead to other applications.

"Ultrasound transducers could be fashioned into flexible, flat insoles to provide sensory stimulation to people who have lost sensation in their feet, including the elderly, who are at such risk of falling," he said. "Surgical instruments could provide tactile feedback to surgeons in training. And I can imagine countless applications for consumer electronics. Users already rely on two-way somatosensory communication with their devices, and peripheral stimulation using ultrasound could add new dimensionalities to this communication."



"One thing we didn't expect is that some brain scans showed activation of pain pathways, yet the volunteers reported feeling no discomfort," Tyler said. "That's an intriguing finding. Though we don't yet know its full implications, being able to activate classic pain pathways without inducing perceptual pain can help us understand how the brain processes pain."

Source: http://www.eurekalert.org/pub_releases/2012-12/vt-npu120612.php



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