The need for educational audiology is growing with the number of children with hearing impairments now included in school systems. This article explains educational audiology and classroom acoustics, key terms to know, new technologies, and how to implement these principles in the classroom.
The Importance of Hearing on Academic Achievement
The ability to hear is crucial to the ability to learn. Educational audiology is a field of study within audiology that focuses specifically on classroom acoustics and a student or teacher's ability to function in the learning environment. Classroom acoustics refer to how sound travels within a classroom or learning space and how it affects academics. The classroom acoustics are considered poor when there is too much background noise and reverberation and when the excess noise interferes with learning and teaching. When classroom acoustics are poor, this can affect speech intelligibility, auditory comprehension, reading and spelling abilities, behavior, attention, concentration, and academic achievement.
Key Terms to Consider
Below are the factors in a classroom used by audiologists and speech-language pathologists when discussing classroom acoustics and educational audiology. All of these aspects of acoustics can affect any student's ability to learn and the teacher's ability to teach:
Background Noise, also referred to as ambient noise, can be generated externally or internally.
Externally generated background noise includes things like the lawn mower, outside traffic, and children playing during recess. This type of background noise usually travels into the classroom mostly through open windows or single-pane windows that are poorly insulated. Many classrooms in older buildings also have older windows that do not prevent externally generated noise from traveling in. Usually the windows are not ideally located, where there is a whole row of windows on one side of a classroom. Classrooms that do not have air conditioning may need to have open windows at times, which brings on a bombardment of externally generated noises.
Internally generated background noise includes things like heating and cooling systems, wall or ceiling fans, the hum of lights, computer noises, hallway traffic, and paper shuffling. It is created within the school or classroom, and this type of noise easily multiplies to distracting levels of background noise. The average classroom has between 18 to 25 students, and when you think of all the noise one student can make, and then multiply that by 20, the noise increases to intensity to the point where it competes with the teacher's voice and the students' attention.
Reverberation is the big word for echo, and more accurately, how much of an echo a room creates. The amount of reverberation is dependent on how much sound is absorbed by the classroom or learning space. The amount of interference from background noise is determined by the ability of the classroom to absorb the energy from the background noises.
Reverberation Time refers to how quickly the classroom can absorb the sound. The reverberation time, or how quickly the echo is generated, is increased when there are high ceilings and bare floors. The increased reverberation time is a direct link to a decreased ability to hear. This is also confounded when there are multiple sounds with different reverberation times and different echoes. Any smooth surfaces in a classroom will increase reverberation time and will degrade the communication within the classroom.
Signal-to-Noise Ratio is the most important aspect of educational audiology and classroom acoustics. Signal-to-noise ration (SNR) is how much louder the teacher's voice is in relation to all the other noises in the classroom.
Here is an example:
The teacher is speaking at a typical loudness of 65 decibels and the background noises all equal 55 decibels, therefore the SNR is +10 decibels. The teacher is speaking 10 decibels louder than the background noises.
The SNR is affected by both reverberation time and background noises. For children, the signal (the teacher) needs to speak 15 decibels louder than the background noise in order to be easily understood. Adults only require an signal increase of about 4 to 6 decibels.
Poor Classroom Acoustics Affect Everyone
Think about this concept of classroom acoustics for a second. Whether your hearing is impeccable or whether you have a severe hearing loss, you could be affected by classroom acoustics. Anyone in a classroom with poor acoustics will be affected, including the teacher.
All children can be affected when it is difficult to hear what a teacher is saying, especially children with the following issues:
- Any type of hearing loss, whether it is in one ear (unilateral) or both (bilateral)
- Temporary hearing loss from an ear infection, fluid build up, or a simple cold
- Any type of learning disability
- Auditory processing disorders
- English language learners or speakers of another language
- Speech and/or language delays
- Attention or behavior problems
The teacher in many cases can also be affected by poor classroom acoustics. When it is difficult to hear because of excess background noise or increased reverberation, a teacher will have to raise his or her voice, causing a strain on the voice. This is problematic when an average teacher uses his or her voice for nearly 60% of the school day. Researchers have found that teachers are 32 times more likely to acquire voice problems than people in similar professions.
Children with and without hearing impairments have difficulty understanding what is being said when classrooms with typical reverberation and typical background noise levels are not amplified. Researchers have studied speech recognition abilities in relation to reverberation time, and have found that when the signal-to-noise ratio is decreased, children fully understand what the teacher is saying.
Creating the Optimal Listening Environment
The American Speech-Language-Hearing Association (ASHA) have created a standard for acceptable classroom acoustics as follows:
- Background noise should be no greater than 35 decibels in an unoccupied room
- Reverberation time should not exceed .6 seconds in smaller classrooms and .7 seconds in larger classrooms
- Signal-to-noise ratio should be +15 decibels
If you think your classroom or learning space is too noisy, you may want to think about some of the following options to change the environment to decrease the noise:
- Place area rugs or carpets over bare floors
- Place felt on the bottom of chair legs if chairs are on bare floors
- Hang blinds or curtains to cover windows
- Hang cork boards or fabric boards on the walls to increase sound absorption
- Create more angles in the classroom to interfere with the pathways of sound
- Turn off any noisy equipment when it is not needed
- When possible, close any doors or windows
- When possible, dim noisy light fixtures
The following list includes ways to adjust lessons to decrease noise:
- Talk to students about noise
- Demonstrate how it can be difficult to hear when there are too many noises occurring at the same time
- When showing videos, keep the class together to watch the video, then explain key points from the video
- Remind students and visitors that when the teacher is talking, no one else should be talking
Another way to increase SNR is to use an FM sound-field system. An FM sound-field system enhances listening comprehension for everyone within the learning space. It increases the SNR, reduces the disturbance of background noises, and increases speech intelligibility.
Facilitate Hearing, Facilitate Learning
The goal for any classroom or learning space should be to create a space where good communication can take place to facilitate learning. When communication breakdowns occur, all aspects of the learning process suffer. It is the responsibility of the educational professionals to ensure that everyone in a classroom can learn and teach for optimal academic performance.