BDNF and hearing loss disorder: Indeed, several studies have shown beneficial effects of BDNF or NT-3 applied to the round window membrane in animal models where SGN function has been compromised by ototoxins or noise [14, 18, 19] In our previous studies, BDNF was administered to the round window membrane by intra-tympanic injection of a thermosensitive sustained-exposure formulation, in a rat model of noise-induced hearing loss and found to provide significant structural and functional amelioration of cochlear synaptopathy [65].