Lane, problems with jaw can cause tinitus, things such as Bruxism or TMJ can mimic problems like Menieres Disease which causes vertigo, tinitus and hearing loss so maybe you biting down alot is causing it in your case.

Lynne, I'm not sure what to suggest. When do your boys tend to notice it more do you know? Things like cola and coffee and such are thought to play a role, do they drink cola at all? Being tired, stressed and certain medications are also thought to make it play up more aswel.

It can be just one of those things that alot of people get though when everything has gone quite, at night say, where there are not many other noisy distractions. Maybe us with SPD do notice it more, its an interesting thought.