Ear infections in the first two years of life can indeed result in dyslexia. Here's why: Dyslexia originates as difficulty in processing the speech sounds of our native language. The International Dyslexia Association says the difficulties of dyslexia "typically result from a deficit in the phonological component of language." That is, it results from a deficit in handling the speech sounds, even with normal hearing. (phonemes = speech sounds.)
Here's the normal process: Babies' brains are primed to listen to and "record" all the sounds that drop from the lips of their parents and caregivers. In English, that's 44 distinct speech sounds. (Each language has its own set.) During our first two years, after hearing the sounds thousands of times, our brains' auditory systems learn to recognize those sounds. These sounds become "mapped" onto the primary auditory cortex, behind the left ear, and arranged in piano-keyboard order, from lower frequency to higher frequency. When we get to school, we use this inner "piano keyboard" to sound out words. Once we learn to associate letters with sounds, the visual images of the letters stimulate our keyboard to play the right sounds in the right order with the right timing. We are sounding out words. We are reading.
But ear infections gum up the process. When a baby has an ear infection, fluid collects in the Eustacian tube --the channel to the brain's auditory system-- and the baby's brain must try to listen through the fluid. It's like listening under water. Sometimes both ears are infected, sometimes only one. In either case, the baby's brain gets less precise impressions of the speech sounds it needs for its piano keyboard (auditory cortex). The incoming sounds may be fuzzy, may be impossible to distinguish from each other, or may be totally imperceptible.
A child with recurring ear infections can end up with a keyboard that's out of tune, mildly or severely, or is missing some keys, or just gets the keys confused with each other. And when the time comes to read, the child is in a world of hurt. The mis-wired piano keyboard just cannot play the right sounds in the right order with the right timing.
This is how ear infections can severely tangle up the child's reading in the very first stage, (phonemic awareness) and create the "deficit in the phonological component of language" that defines dyslexia.
