Tests used for assessing Central Auditory Processing Disorder (CAPD)are generally classified in one of two categories: behavioral or electrophysiologic.
Behavioral tests require a patient to voluntarily respond to some kind of “targeted” stimulus according to prescribed directions. “Targeted” means that the test is designed to “stress” or tax the auditory system in ways which reveal deficits in key auditory functions. The critical elements in behavioral testing include making sure that the tests used are age-appropriate, within the cognitive and language capabilities of the patient, and are administered in a way which is consistent with the conditions used to evaluate the peer-groups when the test norms were established. It is also important that the patient be watched for signs of confusion, fatigue, stress, distraction or non-compliance while testing. Under such conditions, poor test outcomes cannot be confidently attributed to CAPD. In such cases re-instruction, encouragement, taking breaks, or even rescheduling the test appointment may be necessary to obtain quality results.
Electrophysiologic tests (AEPs) measure a specific response from the human body–resulting from various types of stimuli being applied–which is involuntary; i.e., doesn’t require a voluntary response from the patient. This includes some widely-used tests like middle-ear muscle reflexes (MEMR), and otoacoustic emissions (OAEs), both of which provide information on certain aspects of auditory processing.
The more sophisticated electrophysiologic tests, which aren’t available at many facilities, are specialized, auditory-specific electroencephalographic (EEG) measures using electrodes placed on the patient’s head (typically scalp, forehead, and earlobes) to measure brainstem and cortical responses to various auditory stimuli presented through earphones. These are called auditory evoked potentials (AEPs). Most of these AEPs are involuntary, and some can be measured during sleep. Other potentials are best recorded when awake and alert. Some higher, cortical event-related potential (CERP) measurements used for APD assessment DO require the patient to attend to a stimulus mentally in order to get appropriate responses. These tests–both behavioral and AEPs–are useful for both APD diagnosis and to measure pre- and post- effects from therapy used to treat CAPD. EAR-Central, PLLC offers complete diagnostic tests, both behavioral and AEPs.