Hearing traditionally is assessed with tones produced by an audiometer. An audiogram shows the weakest tones that a person can detect at different frequencies.
Vision traditionally is assessed with black letters printed on a white background (e.g. a Snellen Chart). Visual acuity refers to the smallest letters that a person can identify.
New procedures can be used to evaluate whether a person can hear or see well enough to participate in face-to-face conversation. How are these procedures different?
Most people with impaired hearing compensate by watching the speaker’s mouth movements, facial expressions, and gestures. A vision disorder can significantly limit the person’s ability to understand speech.
Vision impairment (e.g., cataract, glaucoma, macular degeneration, diabetic retinopathy) is common in older people. A person with a vision loss may experience one or more of the following difficulties:
reduced ability to see small objects
reduced clarity of objects
reduced contrast sensitivity
limited visual field
reduced ability to distinguish colors
increased interference from glare
It is hard to imagine the experiences of a person with impaired
vision, but it is possible to simulate vision loss. Some simple methods for simulating the effects of vision loss include the use
of "plus" lenses to blur images, goggles to restrict the visual field,
glass or plastic filters to diffuse light, or computer-based software.
For example, you can use Adobe "Photoshop" to illustrate what a person with impaired vision might see during face-to-face
communication:
During conversation, a person may misunderstand and require repetition, clarification,
amplification, and/or visible cues. To assess a person's needs, the
examiner sits at a 1-meter distance, faces the light, and speaks simple
sentences (e.g., "Her father put the milk on the table"). If a
sentence is not heard correctly, the examiner says it again, under progressively easier conditions (repetition, clarification, one
word visible, all words visible) until it is identified correctly. Five sentences are spoken without amplification, and five are spoken while the
person listens through hearing aids or an amplifier/earphones. The results for
24 older people who initially obtained a score of 1/5 without
amplification are shown above, as a function of amplification and successive
test conditions (O = original presentation; R = repetition; C = clarification;
1V = one word visible; AV = all words visible). Note that these 24 people
obtained benefit from both amplified sound and partner cooperation.
[For more information, see: Erber, 1992, 2002; Erber and
Heine, 1995].
Many older people with impaired hearing do not own or use hearing aids. Regardless, they may benefit from amplification of sound. Student therapists engaged 248 older people in face-to-face conversation on familiar topics while these people either listened unaided or through a small amplifier/earphones. In each case, the communication partner held the microphone close to the mouth but not obscuring it. Conversational fluency was rated on a 4-point scale (/1/ = low; /4/ = high). Each box in the matrix (below) compares rated conversational fluency under the two listening conditions. In many cases, people obtained conversational benefit when they listened to amplified sound. [For more information, see: Erber, 1994, 1996, 2002]
The intensity of
airborne sound is reduced as a function of
distance. A therapist talked face-to-face with an older person under three different conditions
(portable amplifier/ALD, hearing aids, no amplification) and six different distances from 0.5 to 3.0
meters. She rated the fluency of each conversation on a 4-point scale (/1/ = low; /4/ =
high). When she used a portable amplifier with a
long earphone cord (with the
microphone near the mouth) high conversational
fluency was obtained throughout this range of distances. Hearing aids were superior to
unaided hearing, but conversational fluency diminished with distance for both conditions. The benefits of near distance and amplification are
evident. [For more information, see: Erber,
1996; 2002; Erber, Holland, and Osborn, 1998]
"Instant Therapy" is any
situational change that immediately
improves a person's ability to communicate. To provide instant therapy, simply modify the
conditions while conversing with the person, and rate the fluency of
conversation under each condition. Assign a number from /1/ (low) to /4/ (high). You may compare effects of
amplification, voice level, distance, rate of speech, the environment, and so forth.
In this example, a therapist modified the
situation (amount of noise, reverberation, illumination, and glare) for an older person in a nursing
home. The
person experienced great difficulty in the noisy and distracting dining room (conversational fluency rating = 1). She
could converse more easily in her own bedroom, which was quiet and less
distracting (conversational fluency rating = 4). [For more information,
see: Erber, 1996, 2002]
You may use a computer and DYALOG software to objectively measure the fluency of conversation before, during, and after any type of communication therapy.
To use DYALOG software, observe the child or adult in conversation (live or recorded). Simply press the "space bar" on the computer keyboard whenever a misunderstanding occurs and "repair" (e.g., repetition, clarification) is needed. Release the space bar when fluent conversation is restored. At the end of the conversation (or after a specified number or minutes), the computer will draw a graph of conversational fluency as a function of time, and also will display:
Each person's results can be printed out or stored in a computer file for later access. Clinicians report that DYALOG software is easy to use, and that the results provide a clear, concise summary of conversational performance. [For more information, see Erber, 1996, 1998, 2002]
To find out more about Sent-Ident, Conversational Fluency ratings, and DYALOG
, see the following article: http://www.hearingreview.com/issues/articles/2003-04_02.aspDYALOG software is available from www.parrotsoftware.com