Hair cell trauma from aminoglycosides, which may lead to permanent loss of hair cells in mammals, was studied physiologically in frogs by measuring an auditory evoked potential (AEP) in Rana pipiens. The AEP was evaluated in order to measure threshold shift (TS) and recovery from TS after the administration of the aminoglycoside antibiotic, gentamicin. To obtain an AEP, chronic electrodes were implanted into the cranium near the cochlear nucleus. The frogs were then exposed to frequency-specific narrow band ~clicks" which included a single period 1 kHz sinewave, and a computer synthesized high frequency and low frequency click. Amphibians have two hearing organs, the amphibian and basilar papillae, sensitive to low (150-1500) and high (1500-2000) frequencies, respectively. The low (AP) and high (BP) frequency clicks were created to stimulate specifically the corresponding papillae. After normal thresholds were recorded for each frog, gentamicin sulfate, 200 μM, 300 μM, or 400 μM, was injected bilaterally into the otic capsules. Thresholds were recorded until the TS had disappeared, allowing the threshold recovery period to be measured. The injections of 200 μM yielded a 10 dB change in one animal and no change in two others. The injection of 300 μM into 10 frogs and 400 μM into 20 frogs yielded at least a 10 dB change in 60% and 93% of the frogs, respectively, with the concentration of 400 μM producing threshold shifts of 20 dB. Thus, the threshold shifts were dose-dependent. Recovery times varied between six and fourteen days. No apparent differences between thresholds for the high frequency click, low frequency click and sinewave clicks were observed.

Thesis (M.S.)--California Polytechnic State University, 2009. / Mode of access: Internet. Title from PDF title page; viewed on Jan. 20, 2010. Major professor: Dr. Lynne Slivovsky. "Presented to the faculty of the College of Engineering, California Polytechnic State University." "In partial fulfillment of the requirements for the degree [of] Master of Science in Electrical Engineering." "July 2009." Includes bibliographical references (p. 102-104).

Thesis (M. Aud.)--University of Canterbury, 2009. / Typescript (photocopy). Includes bibliographical references (p. 87-98). Also available via the World Wide Web.

Thesis (Ph. D.)--Hong Kong Polytechnic University, 2003. / Includes bibliographical references (leaves 199-216). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

Thesis (Ph.D.)--University of Alberta, 2009. / A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Centre for Neuroscience. Title from pdf file main screen (viewed on August 25, 2009). Includes bibliographical references.

Thesis (Ph. D.)--Hong Kong Polytechnic University, 2003. / Includes bibliographical references (leaves 199-216).

Thesis (M.S)--Texas State University, San Marcos, 2005. / Includes bibliographical references (leaves 158-166). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

Thesis (M.S)--Texas State University, San Marcos, 2005. / Includes bibliographical references (leaves 158-166).

Thesis (M. Sc.)--University of British Columbia, 2006. / Includes bibliographical references.

Thesis (M.S.)--University of British Columbia, 2006. / Includes bibliographical references (leaves 40-42). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.