FIG. 4.

LDV results of HB-EGF treatment of chronic tympanic membrane perforations. The figure shows the mean umbo velocity (normalized by pressure at the tympanic membrane) of the control and treatment groups, grouped into frequency bins corresponding to the frequencies used for the ABR and DPOAE measurements. Standard error bars are shown at each frequency. In both groups, the normalized velocity increases from 4.0 to 11.3 kHz before leveling off, although slight differences can be observed at higher frequencies. Overall, no significant difference was found between the two groups except at 31.9 and 46.1 kHz (p < 0.001, p < 0.001), with the treatment group having a smaller LDV score (with the treatment group scoring on average 0.73 and 0.53 for 31.9 and 46.1 kHz, respectively, compared with 1.29 and 1.08 for control).