Auditory Processing Disorder
Other name: Central Auditory Processing Disorder (CAPD)
An "auditory processing disorder" can be explained as a hearing or a listening problem caused by the brain not processing sounds in the normal way. To understand better, it may be helpful to understand very briefly how we hear. A speaker's vocal cords produce a sequence of vibrations that travel invisibly through the air, the listener collects these vibrations which travel into the ears and vibrate on our eardrums, this causes movement of three tiny bones (in the middle ear), that in turn transfer the vibrations into the cochlea (the inner ear) where the cochlear nerve is stimulated and messages sent to the brain for processing. What the listener thinks he "hears" is actually a series of silent electrical stimuli. The brain processes these electrical impulses into sounds, then into words, and finally into meaningful sentences for understanding. APD is a problem converting these electrical impulses into meaning.
APD can affect both children and adults, whether they have any hearing impairment or not. This means that although the ears are working fine, the brain cannot process what it hears. It should of course be noted that there is a difference between hearing and active listening.
With APD it may be difficult to understand speech in the presence of any background noise, if more than one person is speaking at a time, if the person is speaking quickly, or if the sound quality is poor (for example: over a loudspeaker or in an echoey room). It may affect your ability to pinpoint a sound (localise where a sound is coming from), tell which sound comes before another, distinguish similar sounds from one another (such as "hard" and "heart") or enjoy music however most people find it becomes less of a problem over time, as they develop the skills to deal with it.
It's believed as many as one in 10 children could have some level of auditory processing disorder, which may be caused by glue ear, (a common childhood condition in which the middle ear fills with fluid), a severe illness at birth, (such as bacterial meningitis), a head injury or a genetic defect (it sometimes runs in families).
Adults may also be affected, as it can develop later in life and may be caused by age-related changes in the processing of sounds in the brain, a head injury, a stroke, a bacterial infection or any disease of the nervous system in which the myelin sheath of nerve cells is damaged.
You may be referred by your GP to an audiologist (hearing specialist) for tests which may include hearing tests (you are asked to listen to a variety of sounds and respond to them), questionnaires (you may be asked questions such as: "If a friend or family member shouts your name, do you know who is calling without looking to see?"), electrode tests (an eartip or headphones are placed in your ear and electrodes on your head to measure your brain's response to sounds), speech and language assessments or cognitive (thinking) assessments
Once auditory processing disorder is diagnosed, the cause can be then determined and, if necessary, treated.
Whilst there is now evidence of a cure for Auditory Processing Disorder, you can learn to live with it by making some changes to the way you listen. Auditory training relates to exercises you can do to improve listening and communication skills. Practising these exercises can train your brain to analyse sound better. It's important to do this consistently in order to gain the maximum benefit and there are now many computer based training programs now available such as Listening and Communication Enhancement (LACE).
Making changes to the environment can also assist. Be aware of room acoustics and how they affect your ability to understand speech. Rooms with hard surfaces will cause echoes, so rooms with carpets and soft furnishings are normally much better for communication.Reduce unwanted background noise by switching off any radios or televisions and move away from any noisy devices such as fans or machinery. Try to position yourself so you can see and hear the speaker, take note of where the background noise is coming from and ensure it is behind you. (Music speakers in a restaurant for example). Try to sit in good lighting to assist.
Don't be afraid to ask others for help. For example, they can get your attention by calling your name before they talk, speak clearly and slower or emphasise their speech to highlight the key points of the message. A simple repeat of key facts can help but it may be necessary for them to rephrase the message. Remember too that a lot of speech perception can be obtained by observing visual clues of the speaker so simply facing the speaker will aid understanding.