What we call “hearing” is a complex series of events wherein sound pressure waves in the air are converted to electrical impulses in the brain. This process is done through vibration of the tympanic membrane (“ear drum”) and ossicles (“middle ear bones”), which in turn create hydraulic waves that stimulate the sensory cells within the cochlea (the “organ of hearing”). These sensory cells generate the electrical signals that travel along the auditory nerve and onward to the auditory cortex, which is the primary part of the brain where we “hear” sound.
Most often, audiologists are concerned with “hearing” in the sense of audibility, or sensitivity, to different sounds. This is the information we get from a basic hearing test. Because audibility of sound is so important for communication, and because this is the most common disorder of hearing, most patients only ever receive basic hearing tests. However, for individuals who present particular hearing problems despite having good audibility (i.e., they can hear but not understand words or phrases), there may be an auditory processing disorder (APD) present.
APD (“auditory processing disorder”) is diagnosed by evaluating a patient’s ability to understand words or phrases in the presence of background noises, or when the words are made difficult to understand, such as when they are muffled sounding or when they are sped up or slowed down more than normal. For most people without APD, the presence of background noises, for example, will make speech more difficult to understand, but there should still be some ability. For people with APD, there may be a complete inability to understand speech under these conditions.
In our University Physicians Hearing Care clinic, we have access to a series of tests that allow us to fully evaluate APD. Our tests range from basic screening instruments that can take 20 minutes to administer to full test batteries that can take up to four hours to administer. Of course, not all patients require a full test battery. Most often, a screening test is all that is needed in order to determine to presence of an auditory processing problem and to make recommendations for treatment.
Patients who are referred to our clinic for APD testing will first receive an interview by the audiologist and will also usually receive at least a screening test. If the screening test reveals some problems, we will then customize the full test battery for that patient based on his/her reported problem and performance on the screening.
We can evaluate children as young as 7 and adults of any age. The main requirement is that the patient is able to understand the test directions and has the patience to concentrate for at least 20 minutes at a time during testing.
If you have questions about University Physicians Hearing Care's APD program, or if you suspect that you or someone in your care has APD, please feel free to call our clinic and make an appointment for us to evaluate this and to make recommendations for treatment.