Isaac Hartz, 4, plays on a toy keyboard at his Lawrence home.

Toys with decibel levels over 100 dB include the VTech Touch & Teach Turtle.

The Little Tikes Poptones Big Rockers Keyboard.

They’re loud and obnoxious and often go hand-in-hand with being a parent. No, not your kids (good answer, though!) — the little rascals’ toys.

You know, the dump truck with the realistic beep beep beep, the guitar whose batteries never seem to die and the book that “reads” to your kiddo while he’s supposed to be napping.

Ever wonder if those toys are damaging more than just your parental sanity?

“We’ve not had anything loud like that (where) we were concerned about his hearing,” says Lawrence mom Emily Hartz, whose son Isaac is 4. “It’s just annoying to us — he thinks it’s fabulous.”

While children’s toys aren’t necessarily getting louder, some of them are loud enough to damage a child’s hearing if listened to for extended periods of time, says Dr. Hamid Djalilian, director of neurotology and skull base surgery at the University of California-Irvine Medical Center’s Department of Otolaryngology.

Djalilian and researchers at UCI recently tested a number of popular toys to check decibel levels. The American Academy of Pediatrics and the Occupational Safety and Health Administration say prolonged exposure to sound at 85 dBs or above can result in hearing damage. By comparison, a normal conversation is about 60 dBs; a jet plane during takeoff is 120, when heard from several hundred feet away; and jackhammers and ambulances are 130.

Of the toys Djalilian and his team tested in late 2009, 13 had maximum sounds of at least 100 dBs when measured at their speakers, up close. The toys also were measured from a distance of 12 inches, about the length of a toddler’s arm.

Damage control

How much damage noise causes depends on three factors: the decibel level; how often the noise is repeated; and for how long. Dr. Gerald Whiteside, doctor of audiology at Marston Hearing Center, 1112 W. Sixth St., says that it’s not only toys that parents need to worry about.

“No loud sounds are good for hearing. They tend to deteriorate hearing regardless,” Whiteside says. “So, even though the noise can happen at a time when kids are babies, the cumulative effect doesn’t show up until middle age or later. It’s a permanent, gradual hearing loss if it is truly a noise-induced hearing loss.”

Whiteside says that while parents should pay attention to any noise louder than a vacuum coming close to their child’s ears, he’s not necessarily for banning noisy toys.

“I really hesitate to make any broad, sweeping generalizations because there are a number of complicating factors in all of that,” Whiteside says. “To tell somebody, ‘Well, you shouldn’t have any toys that make noise’ — I would hesitate to do that for fear that some patient or some parents would take away any toys other than soft cotton fuzzy things that don’t make any noise at all.”

And what if you already own the loudest toy on Djalilian’s list — The Secret Saturdays Fire Sword by Mattel? Don’t be too concerned. Your child will probably going to lose interest in it before it does any long-term damage.

“If that’s the kind of a noise that has a prolonged signal and kids are doing that for an hour at a time, yeah, it could eventually cause some damage,” Whiteside says. “But the kids aren’t going to be deaf by the time they’re 12.”

Not-so-soothing sounds

That’s possibly why Steve Buren, manager of The Toy Store, 936 Mass., doesn’t get many hearing-related inquiries about toys. Instead, Buren says that when a question is raised about toys and their noise level, it’s usually one of two concerns, and neither have to do with long-term hearing damage.

“If we demonstrate a toy for them and it makes a noise, some people are like, ‘No, that’s no good, it makes a noise.’ Period. They don’t want anything that makes a noise,” Buren says. “On the converse, I get aunts and uncles … who are like, ‘This is for my brother’s kid, I’m getting him back — what do you have that’s really loud?’ They want something really loud and obnoxious. They want the whoopee cushions.”

Lawrence mom Michelle Parmley says she and her two kids — ages 6 and 3 — have been the recipient of such thoughtful gifts — and says she’d much rather share the love than have such noises fall on deaf ears.

“We’ve had grandparents who bought the music set with the drums and everything,” Parmley says. “They think that’s hilarious, and we’ll just say, ‘Well, we’ll just bring it with us when we come to visit.'”