Brainstem evoked response audiometry(BERA) is a useful diagnostic tool for audiological or otoneurological studies but its result is greatly influenced by various test parameters. Many authors have reported differing results and a normal value is not clear yet. We performed the BERA in 23 normal persons(46 ears) to establish the changes of latency to intensity of stimulus click, probability and latency to ipsilateral and contralateral stimulus click, changes of latency to frequencies of logon sound and latency difference of click, logon, and tone pip sound. The results were as follow : 1) As the intensity of click sound was increased, the wave latency was lengthened. 2) The latency of the Contralateral wave was not increased to compare with ipsilateral wave latency. 3) In the presence of contralateral wave, wave V was almost present with ipsilateral and contralateral stimuli. 4) As the frequency of logon sound was increased, wave latency was shortened. 5) Among the click, logon and tone pip sounds, latency of click sound was shortest and tone pip sound was lengthened. But statistical values were not significant(p>.005).
|