FRIDAY MORNING, 20 MAY 2005 REGENCY E, 8:30 A.M. TO 12:00 ...

and hard words, will be described. Work supported, in part, by a research
grant from NIA, R01-AG08293, awarded to the second author, and an
NIH training grant.
5aSC3. Comparison of speech intelligibility measures. Jacqueline S.
Laures and Gary G. Weismer Georgia State Univ., Atlanta, GA 30302
and Univ. of Wisconsin-Madison, Madison, WI
The speech intelligibility of dysarthric speakers is perceptually measured
by one of the following four techniques: direct magnitude estimation
with a modulus, free modulus magnitude estimation, interval scaling, and
transcription. Weismer and Laures 2002 suggest that magnitude estimates
may provide a more complete representation of speech intelligibility
than other methods of measurement because it may be more sensitive to
non-segmental aspects of speech, such as prosody. However, the empirical
data supporting such a statement is quite limited. The purpose of the
current study is to explore the relationship of the four different measurement
techniques to determine if one approach may provide a more accurate
determination of the speech intelligibility of dysarthric speakers.
Twelve listeners measured the speech of six dysarthric speakers and two
healthy control speakers using the four different measurement techniques.
Each speaker produced three sentences twice. The sentences were presented
via a loudspeaker in a sound attenuated booth. Listeners rated the
sentences using the four techniques. The order of techniques used was
counterbalanced. A correlation analysis revealed that the four techniques
were highly related. Implications of this finding are discussed.
5aSC4. Effects of speech-rate and pause duration on sentence
intelligibility in younger and older normal-hearing listeners. Akihiro
Tanaka, Shuichi Sakamoto, and Yô-iti Suzuki R.I.E.C., Tohoku Univ.,
Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
Speech-rate conversion techniques aid speech comprehension by allowing
more time for perceptual and cognitive processes. However, if only
the speech-rate of a telecast is converted, auditory and visual information
become asynchronous. One possible method to resolve the problem is to
reduce the pause durations between phrases; unfortunately, this can evoke
a marked negative effect. For that reason, the present study examines the
effects of the speech-rate and pause duration on sentence intelligibility. We
manipulated the lengths of phrases relative to the original length 0,
100, 200, 300, and 400 ms), and the pause durations between
phrases in a sentence 0, 100, 200, 300, and 400 ms. Listeners were asked
to write down sentences they discerned from the noise. The intelligibility
score increased in younger and older listeners when the speech signal was
expanded. Regarding the pause duration, intelligibility was best when the
pause duration was 200 ms in younger listeners; in older listeners, the
intelligibility score was highest when the pause durations were 200 ms and
400 ms. These results provide evidence that might benefit speech-rate
conversion through better use of pause duration.
5aSC5. Simulation of temporal aspects of auditory aging. Ewen
MacDonald Inst. of Biomaterials and Biomed. Eng., Rm 407 Rosebrugh,
Univ. of Toronto, Toronto, ON, Canada M5S 3G9, macdone@
ecf.utoronto.ca, Kathy Pichora-Fuller, and Bruce Schneider Univ. of
Toronto at Mississauga UTM, Mississauga, ON, Canada L5L 1C6
A jittering technique to disrupt the periodicity of the signal was used to
simulate the effect of the loss of temporal synchrony coding believed to
characterize auditory aging. In one experiment jittering was used to distort
the frequency components below 1.2 kHz and in a second experiment the
components above 1.2 kHz were distorted. To control for spectral distortion
introduced by jittering, comparison conditions were created using a
smearing technique Baer and Moore, 1993. In both experiments, 16 normal
hearing young adult subjects were presented with SPIN sentences in
three conditions intact, jittered, and smeared at 0 and 8 dB SNR. When
the low frequencies were distorted, speech intelligibility in the jittered
conditions was significantly worse than in the intact and smeared conditions,
but the smeared and intact conditions were equivalent. When the
high frequencies were distorted, speech intelligibility was reduced similarly
by jittering and smearing. On low-context jittered sentences, results
for young adults mimicked results found previously for older listeners
with good audiograms Pichora-Fuller et al., 1995. It is argued that the
jittering technique could be used to simulate the loss of neural synchrony
associated with age-related changes in temporal auditory processing.
5aSC6. Comparison of hearing loss compensation algorithms using
speech intelligibility measures. Meena Ramani Dept. of Elec. and
Comput. Eng., Univ. of Florida, P.O. Box 116130, Bldg. 33, Ctr. Dr. Rm.
NEB 444, Gainesville, FL 32611, John G. Harris Univ. of Florida,
Gainesville, FL 32611, Alice E. Holmes Univ. of Florida, Gainesville,
FL 32611, Mark Skowronski Univ. of Florida, Gainesville, FL 32611,
and Sharon E. Powell Univ. of Florida, Gainesville, FL 32611
Sensorineural hearing loss includes loss of high-frequency sensitivity
which results in decreased speech intelligibility. The loss cannot be compensated
by inverting the audiogram because of the non-linear effects of
sensorineural hearing loss frequency smearing, decreased dynamic range,
decreased time-frequency resolution. Several non-linear compensation
schemes exist Half-gain, POGO, NAL-R, Fig. 6, DSL and LGOB and
this paper provides a comparison of those using the objective Perceptual
Evaluation of Subjective Quality PESQ score and the subjective Hearing
In Noise Test HINT. The listening tests were run on 15 unaided hearing
impaired listeners as well as 15 normal hearing listeners using a simulated
hearing loss algorithm. These results show marked improvement in intelligibility
for the compensated speech over the normal speech for both
normal and hearing impaired adults.
5aSC7. A comparative study of perceived, predicted, and measured
speech intelligibility. Michael E. Hermes, Melinda J. Carney, and
Dominique J. Cheenne Dept. of Audio Arts & Acoust., Columbia
College Chicago, Chicago, IL 60605
Intelligibility metrics were obtained using a variety of methods in a
gymnasium that serves as a place of worship. A word list trial, a computer
model, and a computer-based %Alcons test provided the data. The results
were compared in order to gauge their relative accuracy. The data from the
%Alcons testing were found to be unreliable, but a direct relationship was
established between the mean word list test scores and the results gathered
from the computer model. This relationship allowed for a translation of the
scores to %Alcons.
5aSC8. A statistical model for prediction of functional hearing
abilities in real-world noise environments. Sigfrid Soli House Ear
Inst., 2100 W. 3rd St., Los Angeles, CA 90057, Chantal Laroche,
Christian Giguère, and Véronique Vaillancourt Univ. of Ottawa, Ottawa,
ON, Canada
Many tasks require functional hearing abilities such as speech communication,
sound localization, and sound detection, and are performed in
challenging noisy environments. Individuals who must perform these tasks
and whose functional hearing abilities are impaired by hearing loss may
constitute safety risks to themselves and others. We have developed and
validated in two languages American English and Canadian French statistical
techniques based on Plomps 1986 speech reception threshold
model of speech communication handicap. These techniques predict functional
hearing ability using the statistical characteristics of the real-world
noise environments where the tasks are performed together with the communication
task parameters. The techniques will be used by the Department
of Fisheries and Oceans Canada to screen individuals who are required
to perform hearing-critical public safety tasks. This presentation
will summarize the three years of field and laboratory work culminating in
the implementation of the model. Emphases will be placed on the methods
2604 J. Acoust. Soc. Am., Vol. 117, No. 4, Pt. 2, April 2005 149th Meeting: Acoustical Society of America 2604