Preyer reflex test

Gentamycin, for example, damages the hair cells in the cochlear, a measure of the toxicity which can be detected by scanning electron microscopy. There is a clear dose-response relationship between the number of cells destroyed and the increasing dose of gentamycin. The ototoxicity can also be detected in the intact animal by the Preyer reflex test which determines the threshold sound level for particular frequencies which an animal responds to by movement of the external ear. 

The toxicity of gentamycin to the ear may be detected by histopathology or more easily by the Preyer reflex test which measures hearing thresholds for particular sound frequencies. 

---