# Re: cochlear wave travel time

```You could also just stimulate with a tone and time the neural delay. Luckily
this has been done already. Two such examples are:

Anderson, Rose et al (1971) measured oval window to auditory nerve delays in
squirrel monkeys for tones at loud levels (>90 dB SPL). See figure 3. They give:
Delay(ms) = 1.95*frequency(kHz)^(-0.725)

Donaldson and Ruth measured latencies for 65 dB SPL tones in humans using
EEG. See figure 4.
They give:
Delay(ms) = 4.915 + 0.363exp(0.11324*d(mm from stapes))
Or carefully using Greenwood's formula to convert d to f (if I haven't
messed this up) gives:
Delay(ms) = 4.915 + 1230/F(Hz)^0.82
If you are estimating relative delays then you can probably ignore the
leading 4.915 constant here, it is the asymptote independent of frequency.

Hope that helps,
Daniel.

P.S. Here are the BibTex citations.

@article{
Author = {Anderson, D. J. and Rose, J. E. and Hind, J. E. and Brugge, J. F.},
Title = {Temporal Position of Discharges in Single Auditory Nerve Fibers
within Cycle of a Sine-Wave Stimulus - Frequency and Intensity Effects},
Journal = {The Journal of the Acoustical Society of America},
Volume = {49},
Number = {4},
Pages = {1131-1139},
Year = {1971} }

@article{
Author = {Donaldson, G. S. and Ruth, R. A.},
Title = {Derived Band Auditory Brain-Stem Response Estimates of
Traveling-Wave Velocity in Humans .1. Normal-Hearing Subjects},
Journal = {The Journal of the Acoustical Society of America},
Volume = {93},
Number = {2},
Pages = {940-951},
Year = {1993} }

```