Laura W. Kretschmer

Age-Associated Degeneration of Backward Masking Task Performance: Evidence of Declining Temporal Resolution Abilities in Normal Listeners

A backward masking paradigm was employed to investigate temporal resolution capabilities in normal-hearing subjects of increasing chronological age. Results have documented: (1) a 2-, 4-, 8-, and 11-fold decibel magnitude difference for averaged psychoacoustic functions when comparing data obtained from young adults to those of elderly listeners; (2) that backward masking function slopes become significantly steeper with age, especially at very short interstimulus intervals; (3) a significant interaction between age and target frequency; (4) a linear age-associated decrement in presumed temporal resolution abilities, and (5) no significant target frequency difference nor any ear differences existed. Both end organ and central nervous system mechanisms were considered in explaining these findings.

Characterization of the Practice and Attitudes of Genetic Counselors with Doctoral Degrees

Potential advantages and disadvantages of doctoral training in genetic counseling have been debated. In this study, individual interviews were conducted to characterize the practice and attitudes of genetic counselors who have achieved doctoral degrees in any field. Participants (N=31) were more likely to spend time in research and less likely to spend time in clinic than genetic counselors in general. Advantages identified by participants were consistent with theorized advantages, and included increased knowledge, wider research roles, additional opportunities and greater respect. Disadvantages identified by participants focused more on individual perspectives than previously theorized profession-wide disadvantages. These included increased time commitment and decreased patient contact. The attitudes of participants towards the development of doctoral training in genetic counseling were generally positive. The results suggest that doctoral training in genetic counseling would have more benefits than drawbacks for individuals pursuing this degree.

The Attitudes of Parents of Black Hearing-Impaired Students

The parents of 46 black hearing-impaired students were surveyed regarding their attitudes, feelings, and knowledge about their childrens hearing handicaps. Previous research in this area is scanty...

Ambient habitat noise and vibration at the Georgia Aquarium

Underwater and in-air noise evaluations were completed in performance pool systems at Georgia Aquarium under normal operating conditions and with performance sound tracks playing. Ambient sound pressure levels at in-pool locations, with corresponding vibration measures from life support system (LSS) pumps, were measured in operating configurations, from shut down to full operation. Results indicate noise levels in the low frequency ranges below 100 Hz were the highest produced by the LSS relative to species hearing thresholds. The LSS had an acoustic impact of about 10 dB at frequencies up to 700 Hz, with a 20 dB re 1 μPa impact above 1000 Hz.

Noise impacts from professional dog grooming forced-air dryers.

This study was designed to measure the sound output of four commonly used brands of forced-air dryers used by dog groomers in the United States. Many dog groomers have questions about the effect of this exposure on their hearing, as well as on the hearing of the dogs that are being groomed. Readings taken from each dryer at 1 meter (the likely distance of the dryer from the groomer and the dog) showed average levels ranging from 105.5 to 108.3 dB SPL or 94.8 to 108.0 dBA. Using the 90 dBA criterion required by the US Occupational Safety and Health Administration, dog groomers/bathers are at risk if exposure to the lowest intensity dryer (94.8 dBA) exceeds 4 hours per day. If the more stringent 85 dBA criterion and 3 dB tradeoff is applied, less than one hour of exposure is permissible in an 8 hour day. Cautions are recommended for any persons exposed to noise from forced-air dryers.

Further progress with loudness adaptation inside and outside the speech range

Measurement of loudness adaptation at 4000 Hz and below depends on the technique used [Weiler et al., J. Acoust. Soc. Am. 101, 3171(A) (1997); T. Maguire et al., J. Acoust. Soc. Am. 106, 2207 (1999)]. Further comparison of simple adaptation (SA) to the ipsilateral comparison paradigm (ICP) with repeated measures designs again shows adaptation for both techniques at 8000 Hz but stronger effects for the ICP now. At 6000 Hz only, violations of normal curve parameters were again observed but no SA. Observations at 250 Hz for the ICP and SA will be discussed. The difference in adaptation between the two techniques is extreme in the primary speech frequencies but intermediate at 8000 Hz for our repeated measures designs. Further investigation is planned.

Peripheral factors in loudness adaptation with OAE effects

Tone decay (TD), the ipsilateral comparison paradigm (ICP), and the monaural simple adaptation (SA) procedure assess loudness adaptation differently; this may all be peripheral but it has not been previously compared in one study. Transient evoked oto‐acoustic emissions (TEOAE) have their source in the outer hair cells of the cochlear periphery. A significant correlation (r=−0.60) between contralateral suppression of transient evoked OAEs and tone decay adaptation (r=−0.60) has been reported [Collet et al., Audiology 31, 1–7 (1992)]. A significant correlation (r=−0.36) between ICP adaptation and contralateral suppression of TEOAEs has been found [Ernest M. Weiler, Hongwei Dou et al., J. Acoust. Soc. Am. 103, 3052 (1998)]. Comparison of TD, ICP, and SA with suppression of TEOAEs used repeated measures testing of 75 students (20–35 yrs) of mixed nationalities. Significant correlations were found, but not at all values, between TD, ICP, SA, and suppression of TEOAEs at 80, 60, and 70 dB. A principle componen...

Hearing in the speech range as a key to a puzzle of loudness constancy and loudness adaptation

Loudness adaptation has been a controversial phenomenon, partly due to differences in subject behavior at different frequencies, and partly to conflicting results from studies using different methodology. In this study, parallel experiments were run contrasting two methodological paradigms, the Ipsilateral Comparison Paradigm (ICP) and Simple Adaptation (SA). Both used magnitude estimation to assess loudness adaptation—decline—at 60‐dB ANSI. Forty students with normal hearing (ages 18–45) were divided into four groups, tested at 1, 4, 6, or 8 kHz, with ICP vs SA as the within‐groups variable. Results showed significantly greater adaptation in the ICP as opposed to the SA condition at 1, 4, and 6 kHz. There was no significant difference at 8 kHz. Thus mean differences between the two methods were greatest at the frequencies most closely coinciding with the meaningful frequency range of speech, as previously hypothesized [E. M. Weiler et al., J. Acoust. Soc. Am. 101 (1997)]. It is suggested that differences...

Further effects of cochlear loss on ICP loudness adaptation, and loudness constancy

ICP loudness adaptation depends on an ipsilateral comparison paradigm with a short increasing or decreasing referent value to reveal loudness adaptation. Janson et al. [Br. J. Audiol. 29, 288–297 (1996)] found the intensity‐based function for ICP loudness adaptation for those with a high‐frequency loss differed significantly from normal listeners. Loss of loudness constancy in normal listeners was consistent, loss in those with a cochlear loss showed a negative progression as intensity increased, as if it were the inverse of recruitment. The purpose of the present study was to compare ICP adaptation to recruitment. ICP adaptation and recruitment were tested in ten high‐frequency loss (probably noise induced) and ten age‐matched normal hearing individuals. Although the evidence for recruitment was generally found in those with hearing loss, there was no simple relationship to ICP adaptation. Variation among measures of recruitment, implications of abnormal loudness constancy for speech perception, and the possible use of measures of otoacoustic emissions for future studies will be discussed.

Introduction to Clinical Forum

The issues presented in this forum concerning the development of communication and literacy abilities in school-age children who are deaf or hard of hearing are introduced in this article. The author organized this forum in an effort to renew conversation on the topics of teacher talk, the contemporary assessment of communication, best practices in the mainstream, interpersonal and school discourse as organizers for intervention, choosing sign language and sign systems, and working with marginal/at-risk students who are deaf or hard of hearing. The benefits of qualitative research to clinicians and teachers who seek local answers regarding these topics is stressed in the conclusion.