The Auditory System in Reading

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In the last blog we discussed the impact of the visual system on the reading process, more specifically, decoding. There is always much talk about phonics when it comes to reading decoding and it is likely the most talked about feature discussed in current literature. Sally Shaywitz wrote in her seminal book: “Overcoming Dyslexia” that the pathway of phonics is really good for the novice reader who are learning to read, but in order to accomplish reading efficiency, we would need the high speed pathway from the occipital lobe (vision), through the temporal (auditory and timing) and to the pre-frontal cortex for meaning. It is a confluence of developmental skill that creates a proficient reader.

The first aspect to consider in the auditory contribution is if she (or he) is actually registering the sound in the inner ear. Sound occurs through a variety of frequencies and is also embedded in the under and overtones within the speaker’s voice. The listener would need to discriminate the actual sound to be repeated and create an imprint of this particular sound in the auditory cortex. When the listener encounters the same sound again, it could then be anticipated by memory. Coinciding with having difficulty with phonics, parents and clients will frequently also describe additional features of difficulty with sound. One example would be that family members could note that the struggling reader would be called 3 times by name before responding to their call. She would need to “shut down” the auditory system in order to focus on a task. On such occasions family members may schedule a hearing test, which many times result in hearing being “normal”. Hearing is frequently not the issue in phonics (unless there is a medical condition), but it is more likely the registration and processing of the auditory stimulus that can cause trouble. The pathway to the auditory cortex might be disturbed in it’s processing and the actual sound may not make it to the cortex for analysis.

For a client with difficulty in this area, it would be difficult to know if the sound she hears is the same sound that the speaker produced.

Audiologists who specialize in auditory processing disorder (APD) would have much more to say about this area of function. Fact remains: the child needs to register each specific sound with it’s own frequency and intensity on the basilar membrane of the inner ear (Organ of Corti) to create a tonotopic map, which is repeated in the cochlear nucleus of the subconscious brain, and then finally again in the cortex, where the identification between the sound and symbol can be analyzed for the first time. For a client with difficulty in this area, it would be difficult to know if the sound she hears is the same sound that the speaker produced. When she sounds out a different sound than expected, the teacher would repeat the sound, which would be confusing to her. She knows something is wrong by the words of the teacher (that can be understood in context), but isolating the sound she can only reproduce what she is “hearing”.

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Another factor to consider is that the efficient reading pathway is mostly located on the left side of the brain, as is most of language. Since sensory information from the right side of the body travels mostly to the left side of the body and vice versa, it makes sense that the right ear would have to be the leading ear in this process. It would be quicker and far more efficient. In fact, our right ear is supposed to be the leading ear in listening and language, as our left ear is always scanning the environment in order to gain information from around us. In most clients tested for reading difficulties at our center, we would find that they use their left ear as the leading ear, causing a processing speed delay as the information has to first travel to the right brain and then back to the left brain. In most of these cases, we also find a coinciding auditory sensitivity, either in the past or present, as for some reasons (perhaps developmental delay?) the client had to maintain high vigilance to the environment in order to gain control over stimuli. Literature have yet to uncover more about auditory sensitivity, but it is a real issue for many family members as they observe hands over ears, especially when younger and later simply avoiding loud and boisterous social engagements. This is not to say that every client with a decoding issue has this difficulty, but it certainly coincides in a high percentage of cases.

When the teacher reads a story, the child can tune a listening ear to create context from the teacher’s language, using cognitive skill to compensate. But the same child can have great difficulty decoding “nonsense” words and even when decoding appears to be good, spelling may be a difficult, as the same sound to a different visual symbol does not make sense. Homonyms are especially difficult in spelling and it would behoove the family to seek more thorough evaluation particular to the auditory system.

Families can have this difficulty tested from the ages of 6-7 by an audiologist specializing in this area of APD. Bear in mind that accommodative strategies would be different from remediation therapy. Fast Forward has shown some success in remediating reading proficiency and would be a valuable therapy to consider. I found the most success in using Tomatis Sound Therapy (www.tomatis.com) as it also combines the vestibular process as well. Our auditory and vestibular systems share the same cranial nerve in the brain (CN8) and the added bone conduction in Tomatis support the faster processing speed. Using the Forbrain is also an additional tool that we use in conjunction with Tomatis Sound Therapy. (www.atotalapproach.com)

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