This is a self recording audiometry. Various pure tone frequencies are projected with frequencies automatically move from low to high while the patient controls the intensity through a button. Two tracings are obtained one with continuous and the other with pulsed tone. These tracings help in differentiating between cochlear and retrocochlear lesions and organic from functional hearing loss.
Types of Bekesy tracings include:
Type I - In this type continuous and pulsed tracings overlap. This type of tracing is seen in normal hearing or in individuals with condutive hearing loss.
Type II - In this type continuous and pulsed tracings overlap up to 1000 Hz and then continuous tracing falls. This type is seen in cochlear hearing loss.
Type III - In this type continuous tracimg falls below the pulsed tracing at 100-500 Hz even up to 40-50 dB. This is seen in retrocochlear / neural lesion
Type IV - In this type continuous tracing falls below pulsed lesion at frequencies up to 1000 Hz by more than 25 dB. This is seen in retrocochlear / neural lesions
Type V - Continuous tracing is above the pulsed one. This is seen in nonorganic hearing loss