What is APD or CAPD?
An auditory processing disorder (APD), also known as a central auditory processing disorder (CAPD) occurs when children, adolescents and adults have trouble processing what they hear despite having normal hearing sensitivity. In simple terms, this means that the ear works fine, but the brain cannot process what it hears. Individuals with APD may do well in ideal listening situations (such as in a quiet room), but they have difficulties when there is any distortion of the speech signal (background noise, competing messages, ect). People with APD may have difficulty localizing sounds, discriminating speech and/or remembering information that is presented in an auditory manner.
APD is NOT diagnosed based on behavioral symptoms alone, but some behavioral symptoms may help us decide if an APD evaluation is warranted. Although symptoms vary, some symptoms that may be seen in the general population are:
- Trouble hearing in background noise
- Frequently asking for repetition. Says “huh?” or “what?” often
- Responds inconsistently to auditory stimuli
- Difficulty following auditory directions
- Difficulty understanding rapid speech
- Trouble determining where sounds are coming from
- Generally poor listening skills /decreased attention for auditory information
- Easily distractible and restless in listening situation
- Significant difficulties with reading, writing and/or spelling
- Trouble relating sounds to their letters
- Difficulty understanding jokes
- Poor musical skills/appreciation
The assessment really begins with the first phone call from either a parent or professional. The process is slightly different for children and adults. Once an inquiry has been made in the case of children, we will request that a speech-language evaluation and psycho-educational testing be sent to our office for review.
Adults will be reviewed for evaluation candidacy based on their histories. Once we have determined that you or your child is a candidate for an evaluation, an appointment will be scheduled. Individuals who come to the clinic for assessment will be evaluated by a specialist in auditory processing. Following the evaluation, recommendations will be made on an individual basis.
APD testing is a way of evaluating the auditory pathways which are central to the ear. Hearing is a very complex skill; with analysis of sound beginning at the ear and continuing to the cochlea, 8th nerve, brainstem and finally the auditory cortex. A standard hearing test assesses how well a patient detects the presence of a sound. Auditory processing is much more complicated and therefore requires more complicated testing. APD testing is divided into two separate categories: behavioral and electrophysiological. During behavioral testing, patients will listen to stimuli that are much more complicated to process than what is heard during a traditional hearing test. During behavioral testing, individuals will be required to listen to different types of auditory stimuli which include tones, words, sentences and noises. In addition, when warranted, electrophysiological testing which is a non-invasive technique will be conducted. During this type of testing, individuals will sit in a comfortable chair and will have electrodes placed on their ears and forehead. These look like small metal cups and will be picking up signals from the ears to determine how well auditory information moves through the pathway information is being transmitted through parts of the brain.
Who can be tested?
- Individuals 7 years of age or older.
- Normal or near-normal peripheral hearing.
- Sufficient receptive and expressive language skills to understand and respond to the tasks.
- Sufficient cognitive function.
The exact cause of APD is still unknown. We do know that APD does sometimes run in families. We suspect delays are associated with subtle neurologic maturational delays. Under consideration as well is the possibility of subtle structural and/or biochemical differences in the brain which may cause a more disorganized neural relay system. Specific causes related to injury or disease in children are rare. Adults with auditory complaints (yet have normal hearing) can more frequently have known etiologies to their abnormalities. These include certain disease processes such a multiple sclerosis, vascular disease, strokes, hearing injuries and tumors can cause a significant reduction in the ability to process sound. Test results for both types of tests are compared to normative data and a profile evolves telling us which communication skills and auditory neural function(s) are normal or abnormal for a given age. The next step, and most important, is translating this into helpful information with regard to patient management.
No. To date there are no medications or specific procedure which “cure” the symptoms of APD. Most individuals feel a sense of relief knowing why they or their child are struggling with hearing. If you or your child are diagnosed with APD, you will return for a consultation to discuss appropriate recommendations which include therapy and/or strategies. For some, simple modifications in the environment may be sufficient. For others, therapeutic activities, or directed therapy, specific to the disorder may be recommended.