PTA In CP Angle tumors

In CP angle tumor evaluation audiometry is used to plan strategy for surgery depending weather hearing is serviceable or not.

Non-servicable hearing is typcically >50 dB audiogram and spech discrimation of <50% 

Gardner Robertson scale is used for hearing evaluation.

Gardner Robertson Scale

Grade I (good-excellent) 

pure tone audiogram (dB) : 0-30

speech discrimination (%) : 70-100

Grade II (serviceable)

pure tone audiogram (dB) : 31-50

speech discrimination (%) : 50-69

Grade III (non-serviceable)

pure tone audiogram (dB) : 51-90

speech discrimination (%) : 5-49

Grade IV (poor)

pure tone audiogram (dB) : 91-max

speech discrimination (%) : 1-4

Grade V (none)

pure tone audiogram (dB) : not testable

speech discrimination (%) : 0