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Vestibular Stochastic Resonance as a Method to Improve Balance Function: Optimization of Stimulus CharacteristicsStochastic resonance (SR) is a mechanism by which noise can assist and enhance the response of neural systems to relevant sensory signals. Application of imperceptible SR noise coupled with sensory input through the proprioceptive, visual, or vestibular sensory systems has been shown to improve motor function. Specifically, studies have shown that that vestibular electrical stimulation by imperceptible stochastic noise, when applied to normal young and elderly subjects, significantly improved their ocular stabilization reflexes in response to whole-body tilt as well as balance performance during postural disturbances. The goal of this study was to optimize the characteristics of the stochastic vestibular signals for balance performance during standing on an unstable surface. Subjects performed a standardized balance task of standing on a block of 10 cm thick medium density foam with their eyes closed for a total of 40 seconds. Stochastic electrical stimulation was applied to the vestibular system through electrodes placed over the mastoid process behind the ears during the last 20 seconds of the test period. A custom built constant current stimulator with subject isolation delivered the stimulus. Stimulation signals were generated with frequencies in the bandwidth of 1-2 Hz and 0.01-30 Hz. Amplitude of the signals were varied in the range of 0- +/-700 micro amperes with the RMS of the signal increased by 30 micro amperes for each 100 micro amperes increase in the current range. Balance performance was measured using a force plate under the foam block and inertial motion sensors placed on the torso and head segments. Preliminary results indicate that balance performance is improved in the range of 10-25% compared to no stimulation conditions. Subjects improved their performance consistently across the blocks of stimulation. Further the signal amplitude at which the performance was maximized was different in the two frequency ranges. Optimization of the frequency and amplitude of the signal characteristics of the stochastic noise signals on maximizing balance performance will have a significant impact in its development as a unique system to aid recovery of function in astronauts after long duration space flight or for people with balance disorders.
Document ID
20100023296
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Mulavara, Ajitkumar
(Universities Space Research Association Houston, TX, United States)
FROM
(NASA Johnson Space Center Houston, TX, United States)
Fiedler, Matthew
(Wyle Integrated Science and Engineering Group Houston, TX, United States)
Kofman, Igor
(Wyle Integrated Science and Engineering Group Houston, TX, United States)
Peters, Brian
(Wyle Integrated Science and Engineering Group Houston, TX, United States)
Wood, Scott
(Universities Space Research Association Houston, TX, United States)
Serrador, Jorge
(Harvard Medical School Boston, MA, United States)
Cohen, Helen
(Baylor Coll. of Medicine Houston, TX, United States)
Reschke, Millard
(NASA Johnson Space Center Houston, TX, United States)
Bloomberg, Jacob
(NASA Johnson Space Center Houston, TX, United States)
Date Acquired
August 24, 2013
Publication Date
January 1, 2010
Subject Category
Aerospace Medicine
Report/Patent Number
JSC-CN-20699
Meeting Information
Meeting: Neuroscience 2010 40th Annual Meeting
Location: San Diego, CA
Country: United States
Start Date: November 13, 2010
End Date: November 17, 2010
Distribution Limits
Public
Copyright
Other

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