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 >> Home > Library > Abstracts > 2004 Podium Presentation Abstracts

Podium Presentation Abstracts

Tuesday, March 9th

Module I Diagnostic: Hearing and Balance
Module III APD Pediatrics and Cochlear Implants
Tuesday, March 9th

Module II Hearing Science

9:15 - 9:30

Auditory Localization Across Distance
Paula P. Henry, Ph.D.
US Army Research Laboratory, Bear, DE
Tomasz R. Letowski, Ph.D.
US Army Research Laboratory, Aberdeen Proving Ground, MD

Although auditory localization in the horizontal plane has been studied extensively, limited data exist on the relationship between distance and auditory localization accuracy. Two studies were conducted to evaluate auditory localization accuracy in the frontal horizontal plane across loudspeaker-to-listener distances of 4 m, 8 m and 12 m. The listeners' task in both studies was to indicate the perceived source locations of stimuli. In the first study, two signals: an M16 rifle bolt click and a vocal whistling signal were presented in two intensity conditions (natural and compensation for loss of intensity). In the second study, two different stimuli were presented: the air horn on a truck and a bicycle bell. The air horn was presented at two levels: one equal to that of the bicycle bell and one closer to its natural intensity level. Across both studies, localization accuracy decreased with increasing loudspeaker-to-listener distance. Compensation for the loss of intensity with increases in distance did not affect performance. In addition, differences in intensity for the same sound, as presented in the second study, did not affect performance. The effects of stimulus, loudspeaker-to-listener distance and intensity compensation will be discussed as they relate to auditory localization accuracy.

9:30 - 9:45

DPOAEs in the Estimation of Hearing and Sensory Cell Loss
Bob Davis, Ph.D.
Roger P. Hamernik, Ph.D.
Wei Qiu, Ph.D.
Plattsburgh State University, Plattsburgh, NY

Distortion product otoacoustic emissions (DPOAE), permanent threshold shifts (PTS) and outer hair cell (OHC) losses were analyzed in a population of 187 noise-exposed chinchillas to determine the predictive accuracy of the DPOAE for PTS and OHC loss. Auditory evoked potentials recorded from the inferior colliculus of the brainstem were used to estimate hearing thresholds and surface preparation histology was used to determine sensory cell loss. Based on the analysis of DPOAE, PTS and OHC losses the results showed the following: 1) the considerable variability of individual post DPOAE level values for PTS between 5 and 30 dB and for OHC loss between 5 and 40%, results in a broad region of "uncertainty" making it difficult to use the post DPOAE level with confidence to predict the magnitude of PTS and OHC loss within these limits in individual subjects, 2) the post exposure DPOAE level can be used with reasonable confidence to determine if the status of auditory functioning is either normal (i.e., < 5 dB PTS) or abnormal (> 30 dB PTS or > 40% OHC loss) and, 3) the cumulative distributions of DPOAE amplitudes in normal and noise-exposed ears indicate that there is a systematic relation between test performance and the amount of PTS and OHC loss and can be used to assign a level of confidence to these categories for an individual noise-exposed ear.

9:45 - 10:00

Gap Detection and the Precedence Effect
Jennifer J. Lister, Ph.D.
University of South Florida, Tampa, FL
Richard A. Roberts, Ph.D.
American Institute of Balance, Seminole, FL

Older listeners with and without hearing loss often experience difficulty understanding speech in typical environments. Underlying this difficulty may be deficits in temporal resolution and the precedence effect. Temporal resolution is often studied using gap detection, a task similar to the fusion task used to measure the precedence effect. A relationship between gap detection (measured dichotically) and fusion has been suggested. The purpose of this study was to use additional conditions to explore this relationship. Fixed-frequency and frequency-disparate gap detection thresholds (GDTs) and lag burst thresholds (LBTs) were measured for three subject groups: young with normal hearing; older with normal hearing; and older with sensorineural hearing loss. For GDTs, fixed-frequency and frequency-disparate narrow-band noise markers were presented in diotic and dichotic paradigms. For LBTs, fixed-frequency and frequency-disparate markers were presented in a fusion paradigm. Results indicated GDTs were affected by frequency disparity and age, but LBTs were only affected by frequency disparity. Largest LBTs were measured for the fixed-frequency markers whereas largest GDTs were measured for the frequency-disparate markers. Dichotic GDTs and LBTs were significantly correlated for two of the three frequency conditions. These results suggest that gap detection and fusion may influence each other under some conditions.

10:00 - 10:15

Acoustics of the Middle-Ear Air Space in Human Ears
Susan E. Voss, Ph.D.
Cara E. Stepp
Smith College, Northampton, MA

Describing the acoustics of the human middle-ear air space is important because this air space can affect hearing in many pathological conditions, including perforations of the eardrum and surgical reconstructions of the ear [1]. The middle-ear air space portions of middle-ear models vary, and element values are not derived from measurements on ears with intact mastoid cavities. Here, we present measurements from cadaver ears of the acoustic impedance of the intact middle-ear air space, and we use these measurements to develop an analog circuit model for the human middle-ear air space. We use the model to characterize the role of the middle ear cavity on sound transmission through the middle ear, in both normal and pathological conditions (e.g., tympanic membrane perforations and mastoidectomy surgeries).

[1] Voss, S.E., Rosowski, J.J., Merchant, S.N., Peake, W.T. "Acoustic responses of the human middle ear" Hearing Research 150 (2000) 43-69.

10:15 - 10:30

Using Level-Dependent Latencies to Identify Dominant SFOAE Sources
Kim S. Schairer, Ph.D.
Denis Fitzpatrick, Ph.D.
Shawn Goodman, Ph.D.
John Ellison, M.S.
Douglas H. Keefe, Ph.D.
Boys Town National Research , Omaha, NE

It is thought that stimulus frequency otoacoustic emissions (SFOAE) are generated at low levels by linear-coherent reflections from spatially-varying irregularities (place-fixed sources). At higher levels, SFOAEs are dominated either by: A) nonlinear distortion for which latency should be short (wave-fixed sources), or B) place-fixed sources for which latency should be longer, but reduced in comparison to responses at lower levels. The latter could be attributed to a basal shift and/or broadening of the traveling wave. The current study used phase gradient slopes to estimate latency. SFOAEs were elicited in normal-hearing adults from 0.5-4 kHz, with a primary frequency ratio (suppressor to probe) of 1.02-1.03 at 65 frequency steps per octave. Probe levels (Lp) were 40, 50, 60, 65, and 70 dB SPL in different conditions, and suppressor levels were 15 dB above Lp. At low levels, phase gradient slopes were steep, consistent with long delays and place-fixed sources. As Lp increased, latencies were slightly reduced, consistent with a basal shift of the traveling wave. Although latencies were not short enough to indicate nonlinear distortion as the dominant component at high levels, it cannot be completely ruled out as contributing to the response.

10:30 - 10:45

Standardization of Spatial and Speech Audiometry Using Phonemic Contrasts
Angela B. Staley, M.A.
Pamela J. Mishler, Ph.D.
Department of Veteran Affairs, Dayton, OH
Mark Ericson, Ph.D.
Wright Patterson Air Force Base, Wright-Patterson AFB, OH

Understanding one talker in the presence of concurrent speech poses difficulty for many people. This "cocktail-party effect" phenomenon was examined by analyzing the effects of energetic and informational masking. This study examined the effects of energetic and informational masking when two words, spoken by the same person are heard simultaneously. The Modified Rhyme Test (MRT) was used for both target words and masker words. Ten normal hearing subjects, 5 female and 5 male, were instructed to identify target words in diotic and spatial presentations of two-talker and three-talker tasks. The distribution of errors was analyzed by place and manner of articulation. Analysis of incorrect responses showed that listeners indicated that they heard middle place-of-articulation phonemes more than front or back phonemes, independent of the actual spoken phonemes of the talker and masker. Intelligibility predictions from the articulation index, used as a model for energetic masking, produced levels below actual listener performance. Speech maskers affected the distribution of manner-of-articulation errors differently than noise (energetic) maskers. Long duration consonants and fricatives were more salient cues for intelligibility than voicing or stop cues.

11:00 - 11:15

Cortical Activations for Syllable Discrimination Versus Voice Discrimination
E. William Yund, Ph.D.
Christina M. Roup, Ph.D.
VA Medical Center, Martinez, CA
Helen J. Simon, Ph.D.
Smith-Kettlewell Eye Research Institute, San Francisco, CA

As part of a larger study of changing speech perception in new hearing aid users, functional magnetic resonance imaging (fMRI) was used to study differences in cortical activity when individuals performed nonsense syllable versus voice gender discriminations. These fMRI results were obtained before hearing aid fitting; other scans will be done after hearing aid use. Stimuli for the voice gender blocks were isolated vowels. In the nonsense syllable blocks, the same vowel was paired with different consonants. Six sets of syllables were used, including: voiced plosive vowel-consonants (VCs), voiced fricative VCs, voiced mixed-manner VCs, unvoiced plosive consonant-vowels (CVs), unvoiced fricative CVs, and unvoiced mixed-manner CVs. Cortical surface activations were averaged across subjects in the high-resolution FreeSurfer spherical inflation coordinate system (Fischl, et al., 1999, Hum. Brain Mapp. 8: 272-84). Average results for the first six subjects show the largest increase in cortical activation for syllable versus voice discriminations along the superior temporal gyrus (STG) of the right hemisphere (RH) near Heschel's gyrus (HG). The activation increase in the left STG near HG was much less and only approached that of the right STG for the plosive VCs. These results support the role of the RH in simple speech discrimination tasks.

11:15 - 11:30

What Chinchilla Near-field Recordings tell us About the ASSR
Robert Burkard, Ph.D.
Kathleen Szalda, M.A.
Yuqing Guo, M.D.
Sally Arnold, Ph.D.
University at Buffalo, Buffalo, NY

The auditory steady state response (ASSR) has been the subject of intense study over the past few years, and is currently being incorporated into clinical AEP devices for both threshold estimation and auditory screening. A review of the far-field literature, particularly human research, suggests that modulation frequency manipulation changes the generator of the response, and that simultaneous stimulation at more than one frequency has little effect on the amplitude of the response to a single ASSR-evoking component. The present investigation will review a series of experiments using two-tone stimuli or tone burst stimuli to evoke an ASSR in the chinchilla while recording from near-field electrodes placed in or near the inferior colliculus (IC) and/or auditory cortex (AC). We will review the modulation rate transfer functions in the IC and AC, before and after carboplatin treatment, as well as in the unanesthetized and barbiturate-anesthetized chinchilla. We will also review the effects of stimulus type (two-tone versus tone burst) on ASSR response amplitude, as well as the effect of adding a second ASSR-generating component on response amplitude. (Supported by NIH-NIDCD DC03600).

11:30 - 11:45

Perceptual Spectral Centroid Model for Complex-Sound
Discrimination and C-V Identification
Lawrence L Feth, Ph.D.
Ashok K. Krishnamurthy, Ph.D.
Vivek Rajendran, M.S.
Ohio State University, Columbus, OH

The influence of the spectral 'center-of-gravity', or centroid, of complex sounds is evident in vowel identification (Chistovitch and Lublinskaja, 1979) and Voelcker-tone discrimination (Feth and O'Malley, 1977) where the spectral centroid remains stationary for the duration of the signal. More recently, perception of dynamic centroid signals has been reported (Lublinskaja, 1996; Anantharaman, et al., 1997). Listeners are apparently able to track the dynamic spectral 'center-of-gravity' of simple and complex sounds in order to report pitch changes, temporal differences, and C-V transitions. The perceptual spectral centroid (PSC) model was developed to account for the signal processing used by human listeners (Anantharaman, 1998). This presentation will review the experiments that led to the development of the perceptual spectral centroid model and demonstrate its application to recent laboratory results. We asked listeners to distinguish between two dynamic complex sounds that have a common envelope but very different fine structures. The PSC model has been expanded to predict listener performance in these discrimination tasks and in C-V identification.

11:45 - 12:00

Audiometric Predictions Using SFOAE and Middle-Ear Measurements
John Ellison, M.S.
Douglas H. Keefe, Ph.D.
Boys Town National Research Hospital, Omaha, NE

Stimulus frequency otoacoustic emissions (SFOAE), ambient-pressure acoustic transfer function (ATF), and 226-Hz tympanometry were measured in the ear canal to determine cochlear and middle ear contributions to air-conduction thresholds, and to identify hearing loss. SFOAEs were measured by fully suppressing a tone of frequency fp (from 0.5 to 8 kHz) and level Lp using a higher-level tonal suppressor frequency close to fp. ATFs (i.e., reflectance and admittance) were measured between 0.25 and 8 kHz. SFOAE signal-noise ratio (SNR) with Lp=60 dB SPL accounted for most of the variance in the audiogram and best predicted hearing loss. In normal ears, ATFs and tympanometric ear-canal volume weakly predicted the audiogram, meaning that subjects with smaller ear-canal volumes had better thresholds. Adding ATF variables to a predictor based on SFOAE SNR slightly improved predictions of hearing loss at 4 kHz. Compared to other OAE types, SFOAEs were similar predictors of hearing loss at 1, 2, and 8 kHz, worse at 4 kHz, and better at 0.5 kHz. Unlike other OAEs, SFOAEs were present in ears with thresholds exceeding 60 dB HL. SFOAE performance was nearly unchanged when ears with thresholds up to 95 dB HL were included. [Supported by NIDCD RO1 DC03784].

12:00 - 12:15

The Effects of Mild-Moderate Hearing Loss on Frequency Selectivity
Andrea M. Simonson, Ph.D.
Andrew Oxenham, Ph.D.
Massachusetts Institute of Technology, Cambridge, MA

Individuals with hearing loss have often shown poorer frequency selectivity than normal, although this difference generally becomes noticeable only for hearing losses greater than 35 dB HL. The present experiment used a notched-noise method in non-simultaneous and simultaneous masking to derive auditory filter shapes for subjects with mild-to-moderate hearing loss. Non-simultaneous masking is thought to be a more sensitive measure of frequency selectivity than simultaneous masking because it is not affected by suppression. A 3-alternative forced-choice procedure was used to determine the masker level at threshold for a 20-ms signal presented at 10 dB SL in varying notch-width conditions using simultaneous and non-simultaneous masking. Signal frequencies of 1, 2, and 4 kHz were tested. A rounded exponential (roex) function was used to derive auditory filter shapes. Filters derived using non-simultaneous masking were broader than for normal hearing, but narrower than those derived using simultaneous masking, even in listeners with hearing losses of less than 35 dB HL. Implications of these results will be discussed in terms of outer hair cell function, the cochlear amplifier, and the role of suppression in normal and impaired hearing.

12:15 - 12:30

Age and Gap Discrimination: Effect of Processing Load
John H. Grose, Ph.D.
Joseph W. Hall III, Ph.D.
Emily Buss, Ph.D.
Univ. N. Carolina at Chapel Hill, Chapel Hill, NC

Temporal processing declines with advanced age, and independently of hearing loss. The purpose of this study is to determine whether deficits in temporal processing are evident early in the aging process. The hypothesis is that deficits exist in the pre-senescent auditory system for complex tasks using brief stimuli. Three groups of listeners participated in a gap discrimination task. The listeners were young (18-24 yrs.), middle-aged (40-55 yrs.), or elderly (>65 yrs.), with normal or near-normal hearing. Gap discrimination was measured for brief tonal markers that were either proximal in frequency (1455 Hz ± 1 semitone) or distal in frequency (1455 Hz/4000 Hz). Phase I of the experiment consisted of the basic gap discrimination task. Phase II was similar except that the listener now had to determine the pitch direction of the sequential markers in addition to discriminating the gap. This two-tier judgment was intended to increase the processing load required to perform the task. Results to date indicate that gap thresholds are uniformly elevated in the across-frequency condition relative to the within-frequency condition. Variability within listener groups also appears to increase in the two-tier judgment task. Complete results will be discussed in the context of expected age effects.

Tuesday, March 9th

Module III APD Pediatrics and Cochlear Implants

9:15 - 9:30

Specialized fMRI Activation to Dichotic Words in Children
Deborah Moncrieff, Ph.D.
University of Connecticut, Storrs, CT
Richard Briggs, Ph.D.
University of Texas Southwestern Medical Center at Dallas, Dallas, TX
Kaudinya Gopinath, Ph.D.
University of Florida, Gainesville, FL

A significant asymmetry with reduced performance in one ear and normal performance in the other ear on a test of dichotic listening is regarded as an indication of an auditory processing disorder. Functional MRI techniques used to measure cortical activation patterns during dichotic listening tasks in normal listeners have revealed greater activation in left hemisphere with linguistic stimuli and in the right hemisphere with non-linguistic stimuli. In this study, activation patterns were acquired in children while they listened to single syllable words presented in monaural, binaural and dichotic conditions. Children selected to participate represented a range of behavioral dichotic listening results from no asymmetry to significant asymmetry with a left-ear deficit. All children demonstrated greater activation during dichotic listening than during any other listening task with preferential activation in the transverse temporal gyrus of the right hemisphere and the superior temporal gyrus of the left hemisphere. Individual differences in cortical activation patterns during dichotic listening tasks were compared to individual degrees of interaural asymmetry during pre-scanning behavioral testing. Preliminary results suggest that children with greater asymmetry during dichotic listening tests may demonstrate altered activation patterns compared to children with more normal dichotic listening results.

9:30 - 9:45

P-300 Wave Morphology in Children With Learning Disability
Shalini Arehole, Ph.D.
Linda Badon, Ph.D.
Thomas G. Rigo, Ph.D.
University of Louisiana at Lafayette, Lafayette, LA

The purpose of this study was to determine whether gifted children with learning disorder (LD) and non-gifted children with LD who present auditory processing disorder could be differentiated from gifted and non-gifted children without LD using P-300 response. Four groups of children were studied: (1) non-gifted, non-LD, (2) non-gifted, LD, (3) gifted, non-LD, and (4) gifted LD. Subjects ranged in age from 14 to 17 years. Subject groups were matched for age and gender. Gifted subjects were drawn from the local school district's gifted program. Gifted LD subjects were identified on the basis of teacher evaluation of several criteria associated with LD. Non-gifted LD subjects were drawn from the school district's LD program. The P-300 was measured using an "odd-ball" paradigm. Frequent and rare combination of 1000 Hz and 2000 Hz frequencies were presented binaurally.

Results indicated that although the amplitude of P-300 was smaller for the LD group compared to non-LD group, the differences between the groups were not statistically significant. However, it was found that significantly larger proportions of subjects from the LD groups, gifted and non-gifted, manifested poorer wave morphology when compared to non-LD group. Implications of these findings will be discussed.

9:45 - 10:00

Listening Windows in Infants and Adults
Heather K. Parrish, M.S.
Lynne A. Werner, Ph.D.
University of Washington, Seattle, WA

This study asked whether infants listen selectively at a tone's expected time of occurrence. Listeners were 14 7-9-month-olds and 19 young adults, healthy and without risk factors for hearing loss, tested using an observer-based behavioral procedure. Listeners detected a 150-ms, 1-kHz tone in low-pass (2.5 kHz) noise at 20 dB spectrum level. Trial onset was marked by a 100-ms, 12-dB increment in the noise. Tone and no-tone trials occurred equally often. Tones occurred 200, 500, or 800 ms following the increment. Each listener was tested with a fixed delay to determine the level that produced 75-85% hits, with a false alarm rate below 40%. The average levels did not differ across delays. Listeners then completed 32 "mixed" trials with 80% of the tones at 500-ms delay and 10% at each of the other delays, at the predetermined level. With mixed delays, both infants and adults averaged 76% hits at the 500-ms delay, but only 59% and 33% hits at 200 and 800 ms, respectively, a significant difference. Thus, both infants and adults listen selectively at the expected time of a tone, increasing their sensitivity to an expected tone at the expense of sensitivity to unexpected tones.

10:00 - 10:15

Behavioral and Electrophysiologic Findings
From Children With/Without Listening Problems
Susan Dalebout, Ph.D.
University of Virginia, Charlottesville, VA
Lisa Fox-Thomas, Ph.D.
University of North Carolina-Greensboro, Greensboro, NC

This study compared behavioral and electrophysiologic data collected from two groups of children: children with listening problems (N=19) and children without listening problems (N=26). Listening problems were operationally defined as (1) parental concern about listening abilities and (2) poor performance on at least one of five behavioral measures conventionally used to evaluate aspects of auditory processing. Children in both groups were 11 or 12 years old with normal hearing and normal non-verbal intelligence. The following between-group comparisons were examined: amplitude/latency characteristics of ALR components (P1, N1, P2, N2) recorded in a non-oddball, non-attend condition; amplitude/latency characteristics of ALR/P3 components (from standard and deviant waveforms) recorded in an oddball, attend condition; ALR/P3 interhemispheric amplitude/latency differences; P3 interhemispheric cross correlation functions; and behavioral performance on measures of auditory vigilance, oddball auditory discrimination, and same-different auditory discrimination. Expressive/receptive language abilities and phonological awareness were assessed for descriptive purposes. The primary objective was to explore the possibility that one (or more) of the electrophysiologic indices might serve as a marker of deficient auditory processing. Some limitations of this approach will be discussed.

10:15 - 10:30

ERPs and Behavioral Tests In Children With Listening Problems
J. Shea-Miller, Ph.D.
Seton Hall University , South Orange, NJ
Ilse Wambacq, Ph.D.
NJ Neuroscience Institute, Edison, NJ
Virginia Toth, M.A.
Anne Eckert, Au.D.
JFK Johnson Rehabilitation Center, Edison, NJ

This study explores the relationship between behavioral and electrophysiologic (ERP) measures of central auditory processing. We developed a criterion to classify 19 children with and without a history of listening problems as having an auditory-only deficit (AOD) based on eight behavioral tests of auditory processing. Ten children were classified as having AOD. Additionally, ERPs to an auditory gap detection task were used to classify the children as AOD, however this time it was based on a cluster analysis of the ERP temporal factor (TF) scores generated from a principal component analysis. The classification of four children did not agree between the two methods. In order to understand the relationship between the ERP and behavioral measurements Pearson's correlations were computed between TF scores and behavioral measures. TF scores were significantly correlated with the left ear percent correct score for a filtered speech task. These findings suggest that ERPs may reflect a lack of redundancy in the auditory system as measured by a filtered speech task. Interestingly the TF scores were also highly correlated with a parent questionnaire of auditory performance, thereby suggesting that auditory ERPs may have a functional validity in the evaluation of children with listening problems.

10:30 - 10:45

What's in a Name? Hard-of-Hearing Children's Concept of Clothing.
Susan W. Jerger, Ph.D.
Julie Pressley
Kristen Searcy
Meaghan Dougherty
University of Texas at Dallas, Richardson, TX

Categorization is a basic aspect of lexical development. To communicate, children must learn that objects have names (dogs, cars) and belong to conceptual categories (animals, vehicles). This research investigated the development of conceptual categorical knowledge in hard-of-hearing (HH) children (N=30) and normal-hearing (NH) children formed into comparison groups representing similar ages (N=40) or vocabulary skills (N=80). Individual pictures of clothing and non-clothing were presented in a Semantic Verification Test; children pushed the Yes button if a picture was clothing, and the No button if it was not, as quickly as possible. The children were blind to the fact that the pictures represented different "goodness-of-example" exemplars of clothing, ranging from 10 (excellent) to 0 (not clothing). Items represented Strong Yes (e.g., pants: 9.9), Weak Yes (glove: 6.7), Weak No (ring: 2.8), and Strong No (soup: 0.0). In normal adults, reaction times are faster, and errors are fewer, to Strong Yes and Strong No than to Weak Yes and Weak No. Results are assumed to reflect organizing principles in semantic memory. Our data will determine whether HH and NH children show the adult pattern of results, demonstrating appreciation of the "salience" of Strong-Weak Yes exemplars and the "similarity" of Strong-Weak No exemplars.

11:00 - 11:15

Relationship Between ABR and VRA Thresholds in Infants & Toddlers
Yvonne S. Sininger, Ph.D.
Stanton Jones, M.S.
Frances Miranda, M.S.
UCLA Medical Center, Los Angeles, CA
Amy Martinez, M.S.
House Ear Institute, Los Angeles, CA
Alison Grimes, Au.D.
Providence Hearing And Speech Center, Yorba Linda, CA
Elizabeth Guckert
UCLA, Los Angeles, CA

We examined relationships between ABR and VRA thresholds from infants and toddlers seen for diagnostic audiologic assessments. Data were obtained by clinical audiologists specializing in pediatric assessments at facilities in the Los Angeles area using a variety of techniques and equipment. Data from 32 children were evaluated in response to stimuli of 500, 2000 and 4000 Hz. All children were free from visual or cognitive disorders and were found to have hearing loss ranging from mild to profound. The average age at ABR was 8.4 months ranging from 0.4 to 38.7 months. The average age at VRA was 16.1 months ranging from 7 to 34 months. The average time between the two assessments was 6.32 months ranging from 0.7 to 15.3 months. The relationship between ABR and VRA thresholds was only fair (R2 = 0.237) for assessments using 500 Hz stimuli but the predictions were good with 2k Hz (R2 = 0.597) and 4k Hz (R2 = 0.55). Large differences are seen in ABR/VRA data relationships at 500 Hz when tympanometric information is considered but not so for 2 and 4k Hz data. Discussion will focus on potential sources of discrepancy between the two measures. Supported by NIDCD R01 DC04433.

11:15 - 11:30

Noise Induced Hearing Loss and Tinnitus Prevention: Methods and Effectiveness
William Hal Martin, Ph.D.
Susan E. Griest, MPH
Linda C. Howarth
Oregon Health & Science University, Portland, OR

The purpose of this study was to develop and evaluate an innovative noise induced hearing loss (NIHL) and tinnitus prevention program for elementary and middle school students.

NIHL among young people is increasing at alarming rates. Noise related tinnitus will likely follow. A consortium of hearing scientists, clinicians, exhibit developers, museum educators and public health experts have worked together to produce an innovative, interactive, multi-modality educational intervention intended to reduce the incidence of NIHL and tinnitus. "The Dangerous Decibels"? project combines a 12-component museum exhibition and classroom outreach programs with ongoing outcomes research studying the effectiveness of the program and identifying noise exposure activities in the subjects.

Effectiveness of the classroom intervention was evaluated in 1630 1st, 4th and 7th grade students from Oregon and Washington by measuring responses on questionnaires given before, immediately after, and 3 months after a classroom presentation. Issues related to changes in knowledge, attitudes and behaviors regarding noise exposure were studied. Experimental and control classrooms were compared.

Significant improvements were noted in all age groups following the interventions. Follow-up effectiveness varied as a function of student age, and socio-cultural issues, especially in areas of projected behaviors. Multiple, sequential interventions may be necessary for long-term success.

11:30 - 11:45

Everyday Cochlear-Implant Benefit in Prelingually Deafened Adults
Dawn Burton Koch, Ph.D.
Advanced Bionics Corporation, Evanston, IL
Cynthia King, Ph.D.
Advanced Bionics Corporation, Valencia, CA
Irena Vujanovic, M.A.
Northwestern University, Evanston, IL
Mary Joe Osberger, Ph.D.
Advanced Bionics Corporation, Valencia, CA

Speech-perception abilities vary widely in prelingually deafened adult cochlear-implant users, and clinical test results are much poorer in these individuals than in their postlingually deafened counterparts. However, clinical experience indicates that the everyday implant benefit experienced by prelingually deafened adults may not be reflected accurately in audiological test results. A questionnaire was mailed to 65 prelingually deafened adults who had six-month post implant speech-perception data obtained during a clinical trial of the Clarion CI implant. The questionnaire was designed to acquire information about (1) implant and hearing-aid use, (2) educational, family, and occupational demographics, and (3) subjective ratings of quality of life and communication skills. Thirty-four adults (52%) returned the questionnaire. The 34 respondents were classified as poor, moderate, or good; users based upon their six-month CID sentence scores. Preliminary analyses show no effect of group on subjective ratings of quality of life and communication skills. In other words, the respondents' assessments of everyday benefit from the implant were unrelated to their speech-perception abilities. Results of additional analyses will be presented along with a summary of the predictive value of demographic characteristics for implant benefit in this group of unconventional implant recipients.

11:45 - 12:00

Streamlined Programming Study in Newly Implanted Subjects
Jennifer Arcaroli, M.S.
Nancy Plant, M.S.
Pete Arkis, M.A.
Cochlear Americas, Englewood, CO

The objective of this study is to determine if speech perception outcomes with MAPs created using streamlined programming techniques are equivalent to speech perception outcomes with MAPs created using traditional behavioral techniques.

Three streamlined programming techniques are to be evaluated and include:

· First Fit Behavioral: interpolation across five behaviorally measured channels

· First Fit Integrated OR: interpolation across five intra-operative T-NRT values.

· First Fit Integrated IA: interpolation across five initial activation T-NRT values.

Subjects will be randomly allocated to each of the three arms. The sample size for each arm will be identical. In each arm, each subject will receive conventional behavioral programming and the streamlined programming for that specific arm, for a fixed period each, with counterbalanced order. Analyses will be based on within subject differences in performance, both for individual subjects and for the group in each arm. This study design avoids subjects being influenced by the initial prolonged use of the traditional behavioral MAP prior to fitting with streamlined procedures.

A secondary objective of this study is to evaluate the clinician's time associated with using streamlined programming techniques compared to traditional behavioral programming techniques.

12:00 - 12:15

EABR and NRI Measurements in Children Using HiResolution Sound Processing
Mike Sabo
John Macias, M.D.
Phoenix Children's Hospital, Phoenix, AZ
Edward Overstreet, Ph.D.
Advanced Bionics Corporation, Sylmar, CA

We are currently participating in a study examining the applicability of intra-operative and clinically obtained EABR and ECAP recordings in children using HiResolution processing. Given the recent release of both HiResolution and NRI (the Clarion tool for recording the ECAP), little is known about how to use these tools together in the application of pediatric fittings or how to apply findings from previous publications using different devices to HiResolution users. This is because previous ECAP studies 1) used the same pulse-durations for both the ECAP stimulus and psychophysical stimulus - the NRI and HiResolution programs typically have different pulse-durations; 2) the ECAP thresholds were compared to single channel psychophysical measures for the same stimulus electrode - HiResolution programs are fit using a multi-electrode broadband stimulus while the NRI stimulus is single electrode; and 3) the ECAP thresholds were compared to relatively slow-rate psychophysical stimuli - HiResolution programs generally have stimulation rates of 3-5 kHz per channel. Here we will provide an update of our study in pediatric HiResolution users describing 1) our baseline correlations between EABR and NRI thresholds and 2) EABR and NRI threshold correlations to both "every-day" program levels and multi-electrode broad-band stimuli.

12:15 - 12:30

Electric-Acoustic Stimulation of the Cochlea: Multicenter Results to Date
Aaron Parkinson, M.A.
Cochlear Americas, Englewood, CO
Bruce Gantz, M.D.
Chris Turner, Ph.D.
University of Iowa, Iowa City, IA
Dave Fabry, Ph.D.
Phonak, Inc., Warrenville, IL

This presentation describes preliminary speech perception results, in quiet and in noise, from a multicenter study involving the Nucleus Hybrid cochlear implant. For patients with severe and profound high frequency hearing losses (i.e., ski-slope type losses), this device, with its short electrode array, allows electric stimulation of high-frequency hearing, while permitting low-frequency residual hearing to be stimulated acoustically.

Results demonstrate that it is possible to insert a short-electrode cochlear implant without total loss of residual low-frequency hearing. This allows patients to continue using a hearing aid to stimulate residual low-frequency hearing while using a cochlear implant to stimulate high-frequency hearing electrically. With Hybrid stimulation (i.e., electric + acoustic stimulation) patients show improved open-set perception of CNC words as well as improved speech perception in noise as measured by the BKB-SIN test. The results of this study, when completed, will be used to test the viability of developing a speech processor that is capable of processing and stimulating patients electrically and acoustically in the same ear.

 

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