Dawna Lewis, Ph.D.
Children with minimal/mild hearing loss (MMHL) make up more than 5% of the school-age population (Bess et al, 1998). Hearing loss in these children may be bilateral, unilateral or high-frequency (Bess et al., 1998) and may be conductive, sensorineural or mixed.
School-age children with MMHL experience greater difficulties understanding speech in unfavorable listening conditions than their peers with normal hearing (Bess et al., 1986; Crandell, 1993; Ruscetta et al., 2005), yet most communication takes place in such environments. Consequently, children with MMHL may have difficulty:
These difficulties may be particularly detrimental in classrooms, where optimal communication access is essential for learning. A variety of accommodations may be helpful in addressing communication-access needs of children with MMHL in classrooms, such as modifying classroom acoustics and use of hearing technologies.
In classrooms, children’s speech understanding may be impacted by noise, reverberation and distance between talkers and listeners.
Background noise can originate from multiple sources. Examples include:
Reverberation can be simply defined as the reflection of sound within a space. These reflections decay over time after the source of the sound ends and the rate of that decay varies depending on the acoustic properties of the surfaces in the room. Although acoustical standards for classrooms are available (American National Standards Institute [ANSI], 2010), many classrooms fail to meet these standards (Knecht et al., 2002; Picard & Bradley, 2001). The result is a less-than-optimal environment for listening and learning.
A variety of acoustical modifications can address distance, noise and reverberation issues in classrooms (Crandell & Smaldino, 2005). Such accommodations provide a first line of defense for ensuring communication access for children with MMHL. Some accommodations are simple. For example, within classrooms children with MMHL should be seated away from sources of noise such as air conditioning units. Classroom activities also can be adapted to reduce noise produced by children when it is important to be able to hear and understand the teacher. By reducing the distance between talkers and listeners during classroom activities, the overall level of the talker’s voice will be enhanced for the listener and the effects of noise and reverberation on audibility of that voice will be reduced. Other acoustic modifications may take more planning, such as placing children with hearing loss in classrooms in quiet areas of the school building and making acoustic modifications to individual classrooms (e.g., carpeting, acoustic ceiling tiles).
While acoustic modifications can provide important benefits for children with MMHL, they may not always be possible and may not be sufficient for communication access. A variety of hearing technologies are available for use with this population. To varying degrees, these technologies can improve audibility of talkers’ voices and reduce negative effects of distance, noise and reverberation. Decisions about what technology or technologies to choose should be made on an individual basis for children with MMHL. In addition to the audiologist, input from families, educational personnel, and the child him/herself (when appropriate) are important to the decision-making process (American Academy of Audiology, 2013; Cincinnati Children’s Hospital Medical Center, 2009). Information below is meant to provide general considerations for a variety of hearing technologies that may benefit children with MMHL.
Hearing aids amplify the level of sounds at the ear to provide access to information that might be too soft to understand. A variety of hearing-aid types may be appropriate for children with MMHL. These devices will work best when the talker and listener are in relatively close proximity.
These devices are fitted to the ear(s) with hearing loss. Considerations include:
These devices place a transmitter/microphone on the poorer hearing ear and a receiver on the better (normal) hearing ear for individuals with unilateral hearing loss. Considerations include:
These devices are generally intended for conductive or mixed hearing losses. They pick up the signal at the hearing-aid microphone and convert it to vibration. That vibration is sent to the inner ear by bone conduction. Traditional bone-conduction devices are worn on the head and held in place with headbands. Osseointegrated hearing aids are surgically implanted into the temporal bone. While the latter devices were originally intended for conductive or mixed hearing losses, they also have been recommended for some unilateral hearing losses (single-sided deafness). Considerations include:
Remote microphone HAT are designed to maintain the level of a primary signal (e.g., the teacher’s voice) at a constant level above the background noise regardless of the distance between the talker and listener within the transmission range of the system. Typically, the talker wears a microphone/transmitter with the microphone placed at the lapel or worn on the head. The signal is sent to a receiver worn by the listener or to a loudspeaker by one of several means of transmission (infrared, frequency modulation [FM] or digital modulation [DM]). These systems also can be connected to other audio sources within the classroom such as televisions or computers. Additional information regarding HAT in classrooms can be found in
Using Hearing Assistive Technologies in the Classroom: Why, When and How? and
Educational Considerations for Hearing Assistance Technologies (HAT) as part of this series. Here we will focus on considerations for children with MMHL.
With these systems, the child wears a receiver that is coupled directly to his or her ear or is coupled to his or her personal hearing aid(s). They are designed to provide an audible and consistent signal for an individual listener. Considerations include:
With these systems, the signal is sent to one or more loudspeakers that are placed strategically within the classroom or to a small loudspeaker that is placed on the student’s desk. They are designed to provide an audible and consistent signal throughout the learning space or within a targeted listening area. Considerations include:
American Academy of Audiology. (2013). American Academy of Audiology Clinical Practice Guidelines: Pediatric Amplification. Retrieved December 27, 2013 from http://www.audiology.org/sites/default/files/publications/PediatricAmplificationGuidelines.pdf
ANSI (2010), 12.60-2010/Part 1, Acoustical Performance Criteria, Design Requirements and Guidelines for Schools, Part 1: Permanent Schools (Acoustical Society of America, New York).
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Cincinnati Children's Hospital Medical Center. (2009). Best evidence statement (BESt). Audiologic management for children with permanent unilateral sensorineural hearing loss. Cincinnati (OH): Cincinnati Children's Hospital Medical Center; 2009 Aug 20.
Crandell, C. (1993). Speech recognition in noise by children with minimal degrees of sensorineural hearing loss.
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Crandell, C. & Smaldino, J. (2005). Acoustical modifications in classrooms. In C. Crandell, J. Smaldino, & C. Flexer (Eds.).
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Ruscetta, M.N., Arjmand, E.M. & Pratt, R. Sr. (2005). Speech recognition abilities in noise for children with severe-to-profound unilateral hearing impairment.
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