Central Auditory Processing (CAP) Evaluation
Occasionally, results obtained at the time of basic hearing testing are within normal limits, but the patient reports difficulty understanding what people are saying a large percentage of the time. Many times greater difficulty is noted when background noise is present. Testing that evaluates the auditory pathways within the central nervous system or brain may be performed. Several tests that evaluate the central auditory nervous system are available. These tests are more difficult than those included in the basic hearing test battery. During testing of central auditory processing ability, headphones are placed over the ears or insert earphones are placed in the ear canals. Sometimes testing is also performed using loudspeakers. The patient is asked to listen carefully to both words and sentences that are usually presented in noise. The volume of the words and sentences as well as the volume of the background noise can be varied. Some tests involve listening to sounds other than speech.
Central auditory processing tests may suggest difficulty with certain types of sound processing that may in turn suggest changes in function in specific areas within the central auditory pathways. In certain cases, hearing assistive devices may enable listeners to hear better in noisy surroundings