Article in ScienceDaily: Temporary Hearing Deprivation Can Lead to ‘Lazy Ear’
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Amy: Even a brief period of hearing loss damages the neural pathways in children. When a 6 month old, or 1 year old, or 3 year old child is implanted with a cochlear implant, what does this mean? The cortical development has been damaged. That’s BRAIN DAMAGE, folks! How to we treat this, medically? For many years now, Auditory-Verbal Therapy has been treating brain development problems in deaf children.
“They observed that the temporary hearing loss in one ear distorted auditory patterning in the brain, weakened the deprived ear’s representation and strengthened the open ear’s representation. The scope of reorganization was most striking in the cortex (and not “lower” parts of the auditory pathway) and was more pronounced when hearing deprivation began in infancy than in later life. Therefore, it appears that maladaptive plasticity in the developing auditory cortex might underlie “amblyaudio,” in a similar fashion to the contributions of visual cortex plasticity to amblyopia.”
Hearing loss DOES cause over-emphasis of whatever system is available. In one-sided hearing loss, they begin to rely more and reorganize to favor the open ear. In deaf kids, they have to utilize the visual system.
What do we do for kids who have amblyopia? I know the answer to this because I had to do it with my son– we patch the strong eye. It’s a bummer, as they obviously prefer that eye. But within a few days and weeks they transform the ability of the weaker eye. In fact, ours was fixed with a few hours a week within just a handful of months because we were diligent and because Elliot was young. Extrapolate that to kids with hearing loss– younger is better in cochlear implants, bilateral implants for kids who already have one CI, and training in their auditory system should take place routinely and should “patch”
the other system. In the deaf child’s case, this is the visual system. We did this with our deaf kids for the first few months of
AVT– we made sure a toy or our hand or sitting next to them rather than in front was making it difficult for them to utilize visual cues to guess what we were saying. Within a few short months they were cured. My boys started early and therefore finished early.
I remember with Ollie, when we corrected his amblyopia we didn’t even have to patch because we started with glasses that helped relax the strong eye and correct the weak one. The pediatric ophthalmologist was “showing off” my child when he came back in with words to his medical students like “see what happens when you start this process early?” He was 2. Elliot was 5 when he patched, and it took several months rather than just the glasses. The correction was the fastest in my younger child. The same thing has happened with my kids and their CI surgeons– I’ve had the surgeons introduce them to other doctors, proudly, and we’ve been a part of many studies relating to early implantation. It has very little to do with their ability, and everything to do with the age and corrective measures taken at an early age.
“The research, published by Cell Press in the March 11 issue of the journal Neuron, reveals that, much like the visual cortex, development of the auditory cortex is quite vulnerable if it does not receive appropriate stimulation at just the right time.”
If you want your child to have highly developed auditory perceptual acuity, don’t delay.
Melissa: These research findings are evident in practice. Initially, cochlear implants in children were FDA approved at age 2 and older. The FDA then lowered the guidelines to age 18 months and then to age 12 months. Surgeons are now implanting babies as young as age 5 months. Why push this window? As the research shows, auditory deprivation causes lasting deficits. Children who receive a cochlear implant at age 6 months followed by Auditory-Verbal therapy are finished with their therapy more than 6 months before children implanted at age 12 months because, during the critical early language learning years, deficits and delays caused by each month without hearing are exponential. I saw this in my own two daughters. Rachel was implanted at age 2 years 7 months and was in Auditory-Verbal therapy until age 10. Jessica was implanted at age 15 months and completed Auditory-Verbal therapy at age 6. Thus, 16 months earlier implantation translated into 4 fewer years of therapy needed to develop age appropriate language. What was particularly noticeable to me was the difference in ease of language acquisition. Where Rachel had to be taught language concepts such as plurals, past tenses, and pronouns, Jessica picked these concepts up with ease as do children with normal hearing. These are cognitive concepts and, thus, the effect of hearing deprivation on cognitive function is readily apparent. The question some may ask is why not sign with a deaf child and implant later? As this research shows, sign does nothing for the development of the auditory cortex because it is a visual language. Thus, while it may impart language, continued lack of auditory stimulation leaves the auditory cortex vulnerable.
Disclaimer: We have no financial ties to the Auditory-Verbal Approach. We simply have firsthand experience of its benefits for our children.
Tags: Auditory deprivation