Electrocochleographic Study of Mumps Deafness

Abstract

The purpose of this investigation is to study the site of lesions in mumps deafness by Electrocochleography.
Sixteen affected ears of fifteen patients ranging in age from four to fourty-two with the average being 15.5 were investigated. Recording was made in an electrically shielded sound proof room with the use of the transtympanic needle electrode technique. Clicks for measurement of auditory nerve action potential (AP) and short tone-bursts for cochlear microphonics (CM) were used as sound stimuli.
Although the audiometric examination in all cases confirmed no response, the following three categories of cochlear pathophysiological features in mumps deafness can be classified according to CM responses.
1) No AP response and the well-developed CM response: It seemed to indicate that the neural regions related to the source of AP response were impaired, but the organ of Corti was found to be functioning because the recorded CM responses were the same as in a normal hearing subject.
2) Neither AP nor CM response: It seemed to indicate that both the neural and the organ of Corti were impaired severely.
3) No AP response and the decreased CM responses: It seemed to indicate that the neural regions were impaired severely, but the organ of Corti were impaired only partially.