All students are impacted by noise levels in their learning environment. But as students who are deaf or hard of hearing settle into their classrooms each fall, an acoustic assessment of these spaces is one of the most important steps in helping them thrive.
Here’s a look at why classroom acoustics are so vital and how to ensure your child’s classroom is acoustically appropriate.
Acoustical access is important for all students—a student can’t understand a lesson if they can’t hear it. “Classrooms are inherently noisy,” says Jenna Karcher, AuD, an educational audiologist at Clarke.* “There are kids talking, chairs scraping across the floor as they move, papers rustling—it’s part of the learning process.” But the noisy din created in learning spaces can be an impediment to all involved—particularly students with learning challenges, students who are learning English as a second language and those who are deaf or hard of hearing.
For students with hearing loss, optimized acoustics allows them to access the instruction and reduces the likelihood of listening fatigue—an issue when students must work harder to listen in challenging environments.
What happens during an acoustic assessment?
An acoustic assessment looks at the signal-to-noise ratio (SNR) in a room—the “signal” being the sound a listener seeks to access, and the “noise” being any background or interfering sound. Any SNR higher than 0dB represents the level of the signal over the noise. In a classroom setting, the SNR compares the decibel level (dB) of the teacher’s voice to the level of background noise in the room. Jenna says that for students with typical hearing, a ratio of +10 dB is ideal. For students with even mild hearing loss, the ratio should be at least +15 dB.
Jenna says that during an acoustic assessment, she looks at several factors that affect the room’s background noise and reverberation levels. Reverberation in this case refers to ambient noise, such as sounds bouncing off hard surfaces like tile floors or blackboards. “That can make it hard to hear even if a student is using hearing aids or cochlear implants,” she notes.
Some factors are obvious causes of increased sound: a classroom with 30 students will almost always be louder than one with 15. But many other things can affect the overall “noise” in a classroom.
“We do acoustic evaluations at the end of the school year if a student knows which classroom they’ll be in,” Jenna says. “Or more often, I don’t get the chance until the fall** when they start in a new classroom.”
During the evaluation, she uses a sound meter level to take measurements at different points so she can access the room’s ambient noise levels and noise sources. Jenna says the evaluation is ideally done twice—when the classroom is occupied and then unoccupied. But, if she can only do one, assessing the room when it’s unoccupied provides more useful information. “That allows me to look for things that can create background noise such as a noisy HVAC system, open windows that let in traffic noise or noise from the playground, and lockers being opened and closed in the hallway next to the open classroom door,” she says.
To make a personalized set of recommendations for a student, she will consider the above data, as well as the type and severity of the student’s hearing loss, the kind of hearing technology they use and if there are any other relevant medical or behavioral factors.
Each child’s accommodations are unique to them, but one of the most common is the use of a Hearing Assistive Technology (HAT) system. Typically, that means an ear-level receiver paired to a microphone the teacher wears that streams their voice directly to the student’s hearing devices. “Those are critical. They are the gold standard and any child who is deaf or hard of hearing will benefit from a HAT system,” says Jenna, adding that they are also an effective means of reducing listening fatigue since the student doesn’t need to work as hard to listen. On the other hand, if a child is self-conscious or has sensory issues that make the receiver difficult to use, a sound field system might be the better option for them.
Other frequent accommodations are adding soft surfaces such as carpeting to reduce reverberation, adding curtains or window treatments, installing acoustic panels on the walls and using tennis balls or similar items on chair feet to reduce noise.
Giving the student preferential seating is also common and one of the more easily accomplished accommodations — but comes with some nuance. Jenna says teachers typically default to putting children with hearing loss in the front row, which isn’t necessarily the best place for them. “Depending on the age of the student and how often they do group discussions or work, that may not be the best place,” she says. “There are more factors to consider. An otherwise good seat next to a loud HVAC vent is going to be a problem. Or a child with single-sided deafness should sit with their stronger ear oriented toward the teacher and their peers.”
She says that if the student is old enough to be a reliable reporter, the audiologist and teachers should consider any feedback the student gives about how well (or not) they’re hearing. “I can recommend the best system on paper, but it might not fit everyone at all times,” she notes.
An Acoustic Evaluation Isn’t Available—Now What?
As helpful as they are, a formal acoustic evaluation isn’t always an option, unfortunately. There are various reasons for this, including a short supply of educational audiologists who can meet the need. But families and educators can still advocate for some best practices that will benefit all students.
“We can still give the school basic recommendations – tennis balls on the chairs, incorporate more soft surfaces, give a general idea of where a student should be seated based on their hearing loss,” says Jenna. “All of that can be done even if we can’t see the room by looking at the audiogram and consulting with the clinical audiologist.”
Regardless of how the recommendations are made, it’s critical the school takes them seriously. Optimized acoustics are necessary for a student with hearing loss to have equal footing in the classroom. And many of the recommendations for improved acoustics will benefit all students in the classroom.
*We are grateful to Jenna Karcher—a talented professional whose work has impacted so many children who are deaf or hard of hearing and their families—for her contribution to this article. Since our interview, Jenna has moved on from her role at Clarke, and we wish her well in all her endeavors!
** While a fall assessment may sometimes be unavoidable, the Clarke team recommends scheduling an educational audiologist’s visit prior to the start of school to obtain classroom accommodation recommendations, in order for the student who is deaf or hard of hearing to begin the new academic year with those accommodations in place. Caregivers and support staff might suggest that before the school year concludes the educational audiologist conduct acoustic evaluations on any classrooms the student could potentially use the following fall.
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