Some parameters of automatic audiometric thresholds

Threshold measurements were made by two automatic audiometers; (1) continuously variable frequency tracing audiometer with an attenuation step of 0.25 dB; (2) continuously changing discrete individual frequency tracing audiometer with an attenuation step of 1.0 dB. Five trained subjects with bilateral normal hearing, four subjects with unilateral cochlear lesion, and four subjects with unilateral retrocochlear lesion were tested. For both pulsed and continuous tones, there was no observable difference in thresholds between two audiometric measurements for subjects with bilateral normal hearing and for ears with normal hearing in subjects with unilateral hearing impairment. The ears with cochlear lesion indicating abnormal rapid adaptation showed slightly greater separation between pulsed and continuous tone thresholds by continuously variable frequency tracings than by continuously changing discrete frequency tracings. For the ears with retrocochlear lesion indicating abnormal slow type of adaptation, muc...