Why would a very minor hearing loss cause so much trouble for a toddler?

If anyone remembers my friend who was “in denial” about her three year old son’s developmental delay , I have an update. She finally got so upset about her pediatrician that she changed and got a new one. Unlike her first one, this one took her refusal to accept the diagnosis seriously. He discovered a minor abnormality in his ear which was unnoticed by the first doctor. The boy had a very minor hearing loss which was cleared up with very low level hearing aids —the lowest they make or just about.

I was super skeptical about her denial, but I’m amazed by the change in her son. Before the hearing aids, he had no interest in talking and had a vocabulary equivalent to a 12 – 15 month old baby. Now he’s hard to understand, but he’s rapidly adding words to his vocabulary and attempting more than baby babbling and even putting two or three word sentences together. He’s still behind most kids his age, but he’s made rapid strides.

But what’s stranger—his behavior has vastly improved. I used to hate spending time with him because he was constantly throwing huge screaming fits and temper tantrums at extremely minor things. He now rarely throws them (but he still does—just about 1/10th as frequent)

He’s also less clumsy and is showing more interest in coloring and fine motor skills activities. He’s now behaving more like a normal 3 year old and less like a kid with neurological damage, developmental delays and possible autism which was originally diagnosed. He might have a year or two of catching up to do, but his therapists he currently has are all confident that he will catch up.

I am baffled. How could a very minor—almost negligible—hearing loss cause all these problems for a child? I wouldn’t have believed it myself except that her son is almost a different boy overnight after getting his earing aids.