Figure 5.

(Color online) Average tip frequency (octave re: SOAE) as a function of probe frequency (Hz) for SOAE+ subjects (crosses) and SOAE− subjects (circles; n = 16 per group). Tip frequency for unpaired data (subjects 6 and 7) are not presented. PTC tip frequencies tend to be higher than probe frequencies in SOAE+ subjects. The majority of SOAE− subjects demonstrate PTC tips aligned with probe frequencies. Arrows indicate values from inverted tuning curves. There is a statistically significant difference in tip frequency between SOAE+ and SOAE− subjects according to a Wilcoxon Signed Rank Test (p < 0.05, n = 14). Tip frequencies between SOAE+ subjects with low- and high-frequency emissions (using 4.3 kHz has the cutoff) did not differ significantly. Tip frequencies from inverted PTCs were not included in these analyses.