"Revised estimates of human cochlear tuning using otoacoustic and behavioral measures" 
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Christopher A. Shera <br>
Eaton-Peabody Laboratory, Mass. Eye and Ear Infirmary and <br>
Department of Otolaryngology, Harvard Medical School 
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and 
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Andrew J. Oxenham <br>
Research Laboratory of Electronics, MIT <br>
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Abstract: <br>
We develop an objective, noninvasive method for determining the 
frequency selectivity of cochlear tuning at low and moderate sound 
levels.  Applicable in humans at frequencies of 1 kHz and above, the 
method is based on the measurement of stimulus-frequency otoacoustic 
emissions and, unlike previous noninvasive physiological methods, does 
not depend on the frequency selectivity of masking or suppression. 
The otoacoustic measurements indicate that at low sound levels human 
cochlear tuning is more than twice as sharp as implied by standard 
behavioral studies and has a different dependence on frequency.  New 
behavioral measurements designed to minimize the influence of 
nonlinear effects such as suppression agree with the emission-based 
values.  A comparison of cochlear tuning in cat, guinea pig, and human 
indicates that, contrary to common belief, tuning in the human cochlea 
is considerably sharper than that found in the other mammals. The 
sharper tuning may facilitate human speech communication.