Eye movement studies with a vestibular prosthesis/

Vestibular loss, which can manifest as dizziness, imbalance, or spatial disorientation, is widespread and often caused by inner ear hair cell malfunction. To address these problems, we are developing a vestibular implant analogous to cochlear implants for the deaf. This vestibular prosthesis provides pulsatile electrical stimulation to the vestibular nerve. Prosthesis effectiveness is assessed using the vestibulo-ocular reflex (VOR), since the VOR helps stabilize gaze in healthy individuals by evoking eye movements that compensate for head movements. In this thesis, the prosthesis was used to probe the high frequency VOR in squirrel monkeys and guinea pigs. In two studies, modulated stimulation was applied acutely to characterize the VOR between 1.5 and 701 Hz. A third study characterized the VOR response to chronic stimulation with a constant rate of 250 Hz. The VOR has previously been characterized up to 50 Hz in monkeys and 2 Hz in guinea pigs by physically rotating subjects. This range was extended in these studies, by using electrical stimulation from the prosthesis. Eye movement spectral peaks were used to characterize the VOR frequency response. The VOR was measurable up to 267 Hz in squirrel monkeys and 151 Hz in guinea pigs. The magnitude response was similar in both species - it increased gradually with frequency, peaked (at 140 Hz in squirrel monkeys and 50 Hz in guinea pigs), and then rolled off.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2010

Author dc:creator

• Saginaw, Michael A. (Michael Adlai)

Advisor dc:contributor.advisor

• Daniel M. Merfeld.

• Electrical Engineering and Computer Science.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/57680

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/57680