Hereditary deafness in the dalmatian dog.

The temporal bones from 18 deaf Dalmatian dogs were examined with the light microscope, and the cochleo-saccular degeneration process studied. End organ degeneration is already advanced by the age of 4 weeks, whilst loss of neurons in the spiral ganglion was found only in adult animals. Both processes are first evident in the central portion of the cochlea, and increase in extent with advancing age, The implications of these findings for the management of non-conductive hearing loss in man are discussed.