Environmental Sounds Considerations for the Audiologist and the Orientation and Mobility Specialist
Why Sound Is Important to the Child Who Is Deafblind
Unlike a child who is deaf or hard of hearing, the deafblind child’s vision loss interferes with the ability to visually identify sound sources and learn about them incidentally. As a result, students who are deafblind need extensive training from infancy to transition age to learn to detect, discriminate and identity environmental sounds. The continuum of purposeful movement in infancy and early childhood that progresses to independence in the community is often chiefly motivated by sound. It is imperative to preserve sustained access to sounds that are constant such as the dishwasher, the flow of traffic in the background, etc. An awareness, understanding, and ability to utilize this sensory information is essential for developing independence and safety. The child who is deafblind will need to be able detect, discriminate, and identify environmental sounds as well as speech. Once these skills have been developed, the child will need to learn application of the skills for safe and independent movement in their environment. For the deafblind child, noise is information.
Understanding Sound Use for O&M Instruction
Orientation and mobility is knowing where you are, where you want to go, and how to get there. Orientation and mobility services are based on the evaluations and program development done by a Certified Orientation and Mobility Specialist (COMS). Since access to environmental sounds is critical, even for infants and toddlers, it is important that personal amplification does not eliminate these sounds. This creates a dilemma for the fitting audiologist whose primary goal is typically to amplify speech. Consequently, the collaboration between the COMS, audiologist, and the teacher of deaf and the hard of hearing is essential to ensure the child who is deafblind has access to these environmental sounds with amplification.
Discrimination, involves making distinctions between sounds that allow one to categorize and recognize what a sound is or is attributed to.
Audiologist considerations: This will likely require less compression of sound in order to discern differences sounds like idling and accelerating cars or comparing echo sounds in a quiet environment.
Orientation and mobility specialist considerations: When hearing aids are used all sounds get louder and often there is a peak level at which loud sounds are cut off to prevent really loud sounds being relayed to the wearer. Often these sounds are needed to discern something like a city bus from a car.
Identification, involves identifying the presence or absence of sound in the environment.
Audiologist considerations: When noise is removed from an environment in order to optimize the ability to attend to speech, much of the environmental components in the sonic landscape that student who is deafblind uses to relate to their surroundings also disappear. Considering “noise as information” can be very helpful when deciding which sounds to retain for the user.
Orientation and mobility considerations: Because hearing amplification changes some sound qualities, the ability identify sounds can be changed when a student uses an assistive listening device. Many times, hearing aids are set to optimize a student’s ability to attend to speech or even speech through a specific source (e.g. an FM System) by eliminating other surrounding sounds. These are typically the sounds a student would use to relate to their environment while traveling or exercising purposeful movement.
Localization, involves determining the location and direction of a sound source in the environment.
Audiologist considerations: With the elimination or compression of the sound scape the ability to determine where a sound is located and to decipher information about its trajectory can be very challenging. Having bilateral assistance or equalization of intensity to both right and left inputs will allow for great accuracy in auditory perception of the environment.
Orientation and mobility considerations: Just as stereoscopic vision is required for effective depth perception, having a disparity in hearing between the two sides can making accurately localizing sound very difficult. Determining the presence of an approaching vehicle, locating a dropped object, turning toward a sound source, etc. are all affected.
A young deafblind woman and her intervener travel outside.
Many researchers and practitioners in the field of deaf-blindness emphasize that movement is the underlying skill upon which all other skills are built, but limited vision and hearing in children who are deaf-blind may inhibit natural curiosity and the motivation to explore and learn from their surroundings. They need environments, learning opportunities, and instruction that encourage and support movement.
Landmarks are persistent, consistent, and unique sounds. Examples might include sound of a public fountain that runs 24 hours a day and helps an individual to know where they are, or the waves at the shoreline.
Cues are sounds that are not “always” present but give information about where one is. Examples might include the sound of the automatic door at the entrance to the grocery store; it only occurs when you are approaching the door and cues you to the transition from indoor to outdoor, or the sound the elevator makes as it arrives at the level one is standing and often has a unique sonic indicator for the direction of the car, such as one chime for ascending and two chimes for descending.
Clues are sound features that help one to deduce information about their environment, such as hearing a person typing on a computer keyboard or answering the telephone and guessing that you are near a reception desk.
Echolocation
The use of reflected sound to determine the presence and characteristics of features of the environment. This could be hearing a tree (by way of a subtle change in echoes) as one is walking along a sidewalk, or hearing an open corridor in a building to know when to initiate a turn. Passive echolocation is using changes in ambient sound for information about the environment, and active echolocation is generating purposeful noise to be reflected off of surfaces in the environment. Purposeful noises could be a sharp tongue click (very effective as the sound returns to the area it was emitted from, specifically the mouth being relatively proximal to the ears), or the tap of the cane tip on the ground. Often young children will use loud vocalizations, hand claps, or foot stomps on the ground to generate echoes. They may not be consciously aware or able to describe what they are doing but have a functional gain in their ability to orient in their environment by doing so.
