Protective Effects of Ginkgo biloba Extract EGb 761 against Noise Trauma-Induced Hearing Loss and Tinnitus Development

Figure 7

Mean evoked neuronal response (±95% confidence interval) to iso-intensity pure tone stimulation across all recorded units in non-tinnitus and tinnitus perceiving animals. Animals that did not develop a tinnitus percept are grouped in the left column while animals that perceived tinnitus are shown in the right column. Depicted are the mean evoked rates (spikes/s) before (blue) and after (red) acoustic trauma at 2 kHz (yellow bar). (a) Data from untreated animals replotted from an earlier study [31]. 2-factorial ANOVA interaction 𝐹 statistics: NT: 𝐹(13,1866)=3.12, 𝑃<0.001; T: 𝐹(13,5952)=1.54, 𝑃=0.10. (b) Data from vehicle treated animals. 2-factorial ANOVA interaction 𝐹-statistics: NT: 𝐹(13,838)=8.46, 𝑃<0.001; T: 𝐹(13,2772)=1.42, 𝑃=0.14. Note the similarity between these and the untreated animals in the NT as well as in the T group. (c) Data from EGb 761 treated animals showing clear differences to the other two animal groups. The 2-factorial ANOVA shows strong interaction of time of measurement (before versus after trauma) and stimulation frequency in the T (𝐹(13,1970)=5.58, 𝑃<0.001), but not in the NT group (𝐹(13,4420)=0.86, 𝑃=0.59).

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