title: Does Exposure to Diagnostic Ultrasound Modulate Human Nerve Responses to Magnetic Stimulation?
abstract: Ultrasound (US) at diagnostic frequency and power is known to alter nerve potentials; however, the precise mechanism of action is unknown. We investigated whether US alters resting nerve potential to lower the threshold for magnetic nerve stimulation. Seventeen healthy subjects were recruited. For each subject, a 1.5 MHz US imaging probe was placed onto the elbow with the beam directed at the ulnar nerve. The probe was coupled to the skin using standard acoustic coupling gel as would be done for a routine clinical US scan. Ulnar nerve stimulation was performed simultaneously with magnetic stimulation (MS). Successful magnetic stimulation of the ulnar nerve was confirmed with nerve potentials measured by electromyography. There was no significant change in electromyography signal when MS was performed during US exposure. US at the diagnostic frequency and power tested does not alter nerve thresholds with MS. Testing at other frequencies is required, however, before US is negated as a technique to modify MS thresholds.
authors.affiliation: Monash Alfred Psychiatry Research Centre, The Alfred & Monash University Central Clinical School, Melbourne, Victoria, Australia. Electronic address: neilwbailey@gmail.com.
authors.forename: Neil W
authors.initials: NW
authors.lastname: Bailey
authors.affiliation: Department of Neurosurgery, Alfred Hospital, Melbourne, Victoria, Australia; Department of Surgery, Central Clinical School, Monash University, Melbourne, Victoria, Australia.
authors.forename: Philip M
authors.initials: PM
authors.lastname: Lewis
authors.affiliation: Monash Alfred Psychiatry Research Centre, The Alfred & Monash University Central Clinical School, Melbourne, Victoria, Australia.
authors.forename: Richard H S
authors.initials: RH
authors.lastname: Thomson
authors.affiliation: Monash Alfred Psychiatry Research Centre, The Alfred & Monash University Central Clinical School, Melbourne, Victoria, Australia.
authors.forename: Jerome J
authors.initials: JJ
authors.lastname: Maller
authors.affiliation: Monash Alfred Psychiatry Research Centre, The Alfred & Monash University Central Clinical School, Melbourne, Victoria, Australia; Department of Electronic Engineering, College of Science, Engineering and Health, La Trobe University, Melbourne, Victoria, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Junor
authors.affiliation: Monash Alfred Psychiatry Research Centre, The Alfred & Monash University Central Clinical School, Melbourne, Victoria, Australia.
authors.forename: Paul B
authors.initials: PB
authors.lastname: Fitzgerald
mesh_terms: D000328:Adult; D004550:Elbow / Q000294:innervation; D005260:Female; D006801:Humans; D008280:Magnetics; D010812:Physical Stimulation / Q000379:methods*; D012016:Reference Values; D014459:Ulnar Nerve / Q000502:physiology*; D014463:Ultrasonography / Q000379:methods*; D055815:Young Adult
keywords: Electromyography; Magnetic stimulation; Ultrasound