Department of Speech
and Hearing Science
The Ohio State University
Introduction
Hearing and listening are the underlying foundation for learning. Anything that interferes with these abilities can negatively impact learning and academic success. Obviously, peripheral hearing loss — a problem that effects the outer, middle, and/or inner ear and results in decreased ability to hear — can hinder learning in a classroom environment. Fortunately, these hearing losses are generally identified and managed effectively to maximize a child's ability to benefit from auditory instruction in the classroom.
However, auditory processing disorders (APD) — often more subtle in their presentation — also interfere with listening and learning. Children with APD have normal hearing acuity but demonstrate listening problems in the classroom. These children often struggle to learn to read and spell and can exhibit speech and language difficulties, including the inability to discriminate between similar sounds. These disorders are often overlooked or mislabeled in school. In addition, attention deficit disorder (with or without hyperactivity), pervasive developmental disorder, and language learning disabilities, may also result in listening difficulties, and in some cases co-exist with APD.
Hearing - the vehicle for learning
Hearing is the most efficient and effective vehicle for learning. Educators capitalize on this and use auditory-oral instruction as the primary approach in the majority of classrooms. This emphasis on listening can pose difficulties for children who cannot use this information successfully, such as those with APD. Children with APD are more affected by the impact of reverberation, background noise, and distance from the teacher in the classroom than their peers. These children often ask for information to be repeated, describe speech as "mumbly", and misinterpret what is said to them. APD may also make it more difficult for a child to focus on the primary speaker, such as the teacher, when background noise is present. Children with APD can "hear" sounds; however they perceive them in a different way than a "typical" listener. These children typically have normal intelligence but have difficulty making use of auditory information. Since children spend 45-60% of the school day with a primary focus on learning, the potential impact of an APD on learning is clear.
Information carried from the ear to the brain must be of "high fidelity" or the information available to the listener will be faulty. A high quality representation of auditory information is necessary to develop an effective language system, as language development is highly dependent on effective input from the auditory system. Auditory processing disorders can impact language development by impairing the ability to discriminate between speech sounds and to recognize phonemes, which are building blocks for speech production and for reading. In addition, children with ADP may be unable to store a speech message effectively or to process speech at "normal" rates. There is a synergy between listening, speaking, and reading, thus children with auditory processing disorders often have difficulty using language effectively and/or in becoming a successful reader.
APD identification
Although auditory processing disorders can be present from birth, behaviors consistent with APD are frequently first observed in school around ages 6 or 7. APD is thought to result from a problem with the "wiring" that carries the message between the ear and the brain, resulting in a decreased efficiency of auditory information transfer. There may be a genetic component, as it tends to run in families. APD can also be acquired, such as in the case of traumatic brain injury or tumor. It can occur at any age; however those that are present during childhood are of particular concern, due to the demands of listening in childhood, such as developing language skills and using those language skills to acquire new information in school. In addition, much of what children learn is often not directly taught but is "overheard".
When a child is suspected of having APD, an interdisciplinary assessment provides information about the child's abilities and allows for the development of a differential diagnosis. This evaluation is critical, since the behaviors observed in children with APD are often present for other reasons, including attention deficit disorder or global learning disabilities. The audiologic evaluation, peripheral and central, is an integral part of this assessment, in order to rule out a hearing loss and to determine if an auditory processing disorder is present. If the disorder is present, information from the assessment can be used to describe its parameters, including functional auditory performance deficits (ASHA, 1996).
A tried approach to APD management
Once an auditory processing disorder is identified, the results of the evaluation are used to develop a plan for management/remediation. A" triad" approach for treatment is most often developed, which includes direct therapy, compensatory strategies, and environmental modifications. Direct therapy approaches are designed to address specific areas of auditory processing deficits. These may be administered by an audiologist, speech/language pathologist, or educational specialist.
Compensatory strategies are accommodations that help the child to "manage" their APD, and can include metacognitive strategies and listening "tricks". A number of environmental modifications can be provided, with the focus on enhancing the acoustical environment and maximizing the "signal-to-noise" ratio, or the ratio of speech energy to noise energy, which in the classroom environment may be other children speaking or sources such as the heating and air conditioning system.
The children, by virtue of their age and their developing language and auditory skills, benefit from an appropriate acoustical environment. The reason for this being that in a typical classroom the teacher's voice gets softer over distance and due to that, background noise will make speech understanding more difficult.
A more learner-friendly environment may be created by acoustical treatment and/or by use of technology, such as a soundfield FM or infrared system. The concept is to establish a favorable signal-to-noise ratio, generally agreed on as a +10 dB signal-to-noise ratio (or the speech being 10 dB more intense than the non-primary message) resulting in a much more clearly and distinctly audible speech signal.
However, children with auditory processing disorders are more challenged by the impact of poor acoustics than their typically developing peers. Children with APD often require a more favorable signal-to-noise ratio than is available in even an acoustically treated classroom. They require increased predictability and redundancy of the auditory signal.
Preferential seating, often recommended for children with APD, offers no acoustical advantage in terms of listening and learning. It has been documented that children with APD require a +12 to +20 decibels signal-to-noise ratio, meaning that the speaker's voice needs to be between 12-20 decibels louder than the noise in the environment. This type of enhancement can only be provided by a personal FM system.
However, systems available in the past were either designed for people with peripheral hearing loss, resulting in the possibility of over-amplification in a child with normal hearing, and/or were body worn devices, a style that may be perceived as undesirable by children and their parents.
EduLink - the Link to Learn
Designed specifically for listeners with normal peripheral hearing acuity, the EduLink is a miniaturized FM receiver that can be utilized with all Phonak FM transmitters. The child wears a discreet receiver which can be quickly fit by an audiologist. The transmitter with microphone can be small and portable for use by the classroom teacher or other speakers, such as the child's peers. The EduLink provides considerable flexibility as it can be used in many learning situations, including "specials" (e.g. art, music), school assemblies, field trips, and lunch, and is not tied to learning happening in a classroom environment. Its open fitting also allows the child to feel tuned-in with their learning environment. The EduLink can provide the listener with a favorable signal that allows for increased message predictability and redundancy, critical factors for children with APD.
The EduLink can help overcome the listening and attention issues that often accompany APD. However, as with any technology, a careful fitting process must be established to determine effectiveness of the EduLink for an individual child and to assure success. Training in the use and care of the EduLink is crucial. In addition, pre-post fitting assessment should be implemented, including verification of fit by an audiologist and functional assessment, using a tool such as the Listening Inventory for Education (L.I.F.E.) (Anderson and Smaldino, 1998) questionnaire completed by both the teacher and child. The EduLink is an important option in enhancing the student's ability to access auditory information in the classroom and can augment the other management strategies implemented.
Although it is not a panacea for APD, use of the EduLink allows the student greater control over their listening environment and improved access to auditory information, which sets a solid foundation for learning.
Auditory problems can exist for reasons other than APD. Although these issues generally do not result from deficits of the auditory system, their functional impact can be in areas of listening and auditory learning. Children with attention deficit disorder, pervasive developmental disorders, global learning disabilities, and English as a Second Language may benefit from the enhanced signal-to-noise ratio provided by the EduLink. A trial with the device, supervised by an audiologist, can identify potential benefits for these listeners.
The EduLink offers an effective way of overcoming limitations present in the acoustic environment and provides access to auditory information for listening and learning in the classroom.
It is a flexible solution designed specifically for children with normal hearing sensitivity. The EduLink can provide the listener with greater control over their listening environment, linking auditory information to learning.
References
American Speech-Language-Hearing Association (1996). Central auditory processing: Current status of research and implications for clinical practice. American Journal of Audiology, 5, 41-54.
Anderson, K. and Smaldino, J. (1998). Listening Inventory for Education (L.I.F.E.) Tampa, FL: Educational Audiology Association.
Crandell, C., Smaldino, J., and Flexer, C. (1995). Soundfield FM: Amplification theory and practical applications. San Diego, CA: Singular
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