Think your teen lives to ignore your every word?  It may just be that she can't hear you.

A new national study has found that one in five teens has lost some hearing, and the problem has gotten worse in recent years. Nobody knows for sure exactly what's causing the hearing loss, but earbuds and digital music are the prime suspects.

The researchers analyzed data on 12- to 19-year-olds from a nationwide health survey. They compared hearing loss in the 3,000 kids tested from 1988-94 to the 1,800 kids tested over 2005-06. Over the two time periods, the prevalence of hearing loss increased from about 15 percent to 19.5 percent. That calculates out to about 6.5 million teens with at least slight hearing loss.

Most of the hearing loss was "slight," defined as inability to hear sounds at 16 to 24 decibels — things like a pin dropping or a mom whispering "good night."  

If your teen is permanently connected to her earbuds, don't stress. Just suggest to her that she turn down the volume a notch or two. Normal conversation tunes in around 60 to 70 decibels, so she should still be able to hear you just fine.

Unless she's just ignoring you.

1 in 5 teens have hearing loss
National study finds a shocking one in five teens has experienced some level of hearing loss.