Brainstem auditory evoked potentials (BAEPs) recorded at
different sound stimulation intensities (after Legent).
of recording is a type of objective audiogram.
The measured potentials
are weak (< µV) and so many summations may be necessary
(1000 to 2000 rrepetitions) before a cleare response emerges from
the background noise.
Note the presence of 5 obvious waves at 70
dB. As the intensity of the presented sound decreases, the latency
of the response increases and the amplitude of the waves diminishes.
The audiometric threshold is defined as the minimum intensity
needed to obtain a clear wave V, which here, as is usual in a
normally hearing subject, is 20 dB.