Notes from When the Brain Can't Hear by Terri James Bellis, Ph.D.
Soon after Auditory Processing Disorder was recognized, Dr Jack Katz defined it as "what we do with what we hear". Auditory processing is everything that happens with sound beyond our ears.
Common symptoms of an APD include having difficulty understanding speech despite having normal hearing, which can look like asking people to repeat themselves often, having trouble following a conversation, and can be made worse when there is background noise such as a tv or music playing or being in a noisy place like a restaurant. Sounds in general or speech may sound muffled or distorted, as if the person is underwater, may take longer to comprehend, or certain speech sounds may be missing or hard to distinguish from others. Some sounds may be indistinguishable. The person's memory for auditory information may be especially poor. They may also frequently misunderstand people, which can lead to frustration and irritation. The effort of having to strain to listen can be exhausting and can lead to fatigue and burnout. So much of the social lives of people involve spoken communication that anything that gets in the way of that can lead to social isolation.
Chapter One, The Many Faces of APD
-In young children especially, it can look as though they have a hearing impairment or are deaf. In schoolage children it can make it hard for them to keep up in the classroom, to follow along with the teacher, and to make friends.
-Having an undiagnosed disorder such as APD can lead a person to conclude that they are stupid and lead to feelings of inadequacy and ignorance, because they don't understand why they struggle and can't do what the people around them seem to do easily or effortlessly.
-APD can cause children to struggle to learn to read and write and keep them functioning at low academic levels and can show up as a noticeable difference between the quality of work the child produces and their abilities with oral language or other abilities. Specific reading skills that may be impacted include decoding (sounding out words) and auditory discrimination abilities.
-Other signs of APD in children can include speaking out of turn, saying things in conversation that are off-topic, avoiding conversation or speaking in class, difficulty following instructions, difficulty taking in information presented verbally,
-A nonverbal child can be taught to do something, such as drop a block into a bucket, to indicate that they have heard a sound. This is one way of doing a hearing test and is called Conditioned Play Audiometry. It's very difficult to diagnose a child under the age of about 7 because they must be able to repeat things such as numbers, words, and sentences. In Auditory Electrophysiology, the way a child's brain responds to sound is recorded by electrodes placed on their scalp. This is a way to test the central auditory nervous system and create a neural representation of the way the child's brain "hears" sound.
-In addition to the type of APD that affects abilities around speech, which is localized to the left hemisphere, the right hemisphere can be affected by Right Hemisphere Disorder, which has very different symptoms. Pragmatic speech is affected, which is how we use speech and the social aspects of speech, so the person may interrupt, not follow convention as far as greetings, etc go; may stray off topic, and may not understand the implications of tone of voice such as the intent of the speaker or the presence of things like irony or humor. Additionally, the sound of the person's speech such as the rhythm may sound odd. Right hemisphere dysfunction is also characterized by depression. One form of right hemisphere dysfunction is called Non Verbal Learning Disorder (NVLD).
-Another type of APD is when the two hemispheres of the brain aren't able to work together well, called interhemispheric integration, which results in binaural deficits. This can show up as difficulty when different inputs are given to each ear at the same time, and in identifying tones. This type becomes more common as people age.
This is how the author responds to those who doubt that APD is real:
"Some children and adults exhibit extreme difficulties in primarily, if not solely, the auditory modality that affect their day-to-day learning and communication abilities.
For the majority of these individuals, hearing loss simply cannot account for their difficulties.
These individuals exhibit specific patterns of findings on tests of central auditory function that precisely mirror those of known pathologies involving the central auditory nervous system and nothing else, which cannot be ignored or put down to mere coincidence."
