Audiology in the Classroom: Modifying the Classroom Environment for Students Who Are Deaf or Hard of Hearing

The issue

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During the last two decades, the population of deaf and hard-of-hearing (DHH) children has changed tremendously due to universal newborn hearing screening, early intervention, and cochlear implants (CIs). This has led to changes in communication approaches, educational settings, and educational demands of these DHH learners. An increasing number of DHH students now rely on digital hearing aids and/or CIs and are educated through spoken language, often in general education classrooms. Adapting the classroom for effective learning by these students is a challenge for educational professionals working with them.

What we know

Classrooms are intended for learning, and most of that learning is mediated by speech, especially in general education classrooms, where most DHH children now are educated. Those DHH students who use spoken language in the classroom need to hear the speech of the teacher and other students clearly. The amount of spoken language that actually reaches the ear of the listener depends on the intensity and the intelligibility of the speech, but also the acoustic properties of the room. Poor acoustical environments reduce speech perception in hearing children with auditory processing disorders such as auditory neuropathy, those with hyperactivity (ADHD), and those who are second language learners even more for DHH students.

Many DHH students today achieve excellent speech perception in quiet, and teachers may underestimate the difficulties they have due to the distance from the speaker, background noise, and sound reverberation. As speech sounds travel away from the talker, 6 decibels (dB) of amplitude (loudness) is lost for every doubling of distance, which means that a listener who is standing 3 meters (10 feet) away might perceive speech at an average level of 56 dB sound pressure level (SPL), but a listener 6 meters (20 feet) away would hear the same speech at a level of only 50 dB SPL.

To avoid speech reception being reduced by noise, the average level of speech needs to be at least 15 dB above that of the noise. In a classroom with background noise of 55 dB SPL and teacher’s speech of 60 dB SPL (+ 5 dB SPL > the noise), only about 50% of the speech likely will be perceived, far below the criterion of 90-100% audibility required for children’s understanding in a learning environment. More distractible students with a hearing loss and students with ADHD may require a speech to noise ratio that is even higher.

Another enemy of good speech perception is reverberation in the classroom, that is the persistence of sound because of multiple, repeated reflections from the room’s surfaces (essentially echoes). As a result, by the time it reaches the listener, the reflected sound is weaker than that if traveling directly from the talker.

Adapting the classroom for effective learning of current population of DHH students is a big challenge, but the following classroom adaptations will have positive effects on the reception of speech and learning by those DHH students who use spoken language:

  • Keeping the distance between the teacher and student below 10 feet so spoken language can be supported by speechreading;
  • Consulting Teachers of the Deaf on how to ensure the best use of personal assistive listening devices and Classroom Audio Distribution Systems (CADS), for example by checking and learning how to troubleshoot equipment regularly, teaching students to manage their own equipment, and so on;
  • Reducing noise from outside by closing windows and placing classrooms with DHH students as far as possible from noise sources (playing fields, roads, construction);
  • Reducing noise within the school by closing doors and thinking about noise control during class, seating deaf children away from noise sources (HVAC systems), sticking pads on the bottom of chair and table legs, using CADS if available, turning off computers and other equipment when not in use.

What we don’t know

To further improve the listening conditions in the classroom for DHH students, CADS such as FM-systems, T-loops, or remote mics using Bluetooth (or a combination) can be connected to one or both of a child’s hearing aids/CIs. Most audiologists encourage connecting to both devices, but some clinicians prefer to connect to one device all the time or in certain communication situations (e.g., group interactions). Audiologists also argue about the use of remote microphones by the teacher versus the microphone(s) on the students’ hearing devices. To date, there is no evidence to suggest that one method or the other provides superior or quicker outcomes. That decision should be made on a case-by-case basis.
Additionally we have to remember that CADS may improve the acoustical environment in formal learning situations (in the classroom) but not in more informal situations where children also learn from others incidentally (on the playground).

Implications

For DHH students who depend on spoken language, optimizing acoustics in the classroom and other school rooms will benefit interpersonal communication and learning (both intentional and incidental). Teaching students to manage their own HAT and teachers’ understanding of the use of technologies such as FM systems, loops, and so on also will improve access to spoken language and other auditory stimuli, potentially supporting learning and reducing barriers to effective communication.

Posted on Jan 11, 2016 by
Leo De Raeve
ONICI, Independent Information and Research Centre (Belgium)
Leo.De.Raeve {at} onici.be

Further reading