So I looked back at his medical records...
I first brought up problems with his hearing in Feb. 2012.
He was screened six months later. Here are the results:
Left:
500hz: 20db
1000hz: 5db
2000hz: 5db
4000hz: 5db
Right:
500hz: 20db
1000hz: 15db
2000hz: 5db
4000hz: 5db
This was considered a pass but I am learning (by lots of googling) that maybe this was a borderline pass and maybe indicative of some hearing loss.
He has several risk factors for hearing problems - preterm, NICU, jaundice
Anyone more familiar with these test?
His teacher also mentioned last year that he had trouble distinguishing between similar sounds. He makes similar errors when speaking.
It's only a "barely pass" on the 500Hz level, because 20db at any normally audible frequency is considered normal.
At the low end of decibels, the results are easily influenced by wax or other objects in the ear. I failed a hearing test once because a bit of cotton swab fuzz had gotten wedged up against one eardrum.
