Biomedical subjects

S Gordon-Salant

Publications and source records attributed to S Gordon-Salant.

At least 19 recordsLinked to original sources

PubMed2001

Sources of age-related recognition difficulty for time-compressed speech.

Older people frequently show poorer recognition of rapid speech or time-compressed speech than younger listeners. The present investigation sought to determine if the age-related problem in recognition of time-compressed speech could be attributed primarily to a decline in the speed of information processing or to a decline in processing brief acoustic cues. The role of the availability of linguistic cues on recognition performance was examined also. Younger and older listeners with normal hearing and with hearing loss participated in the experiments. Stimuli were sentences, linguistic phrases, and strings of random words that were unmodified in duration or were time compressed with uniform time compression or with selective time compression of consonants, vowels, or pauses. Age effects were observed for recognition of unmodified random words, but not for sentences and linguistic phrases. Analysis of difference scores (unmodified speech versus time-compressed speech) showed age effects for time-compressed sentences and phrases. The forms of time compression that were notably difficult for older listeners were uniform time compression and selective time compression of consonants. Indeed, poor performance in recognizing uniformly time-compressed speech was attributed primarily to difficulty in recognizing speech that incorporated selective time compression of consonants. Hearing loss effects were observed also for most of the listening conditions, although these effects were independent of the aging effects. In general, the findings support the notion that the problems of older listeners in recognizing time-compressed speech are associated with difficulty in processing the brief, limited acoustic cues for consonants that are inherent in rapid speech.

Adult↗

PubMed2001

Aging and temporal discrimination in auditory sequences.

This study examined age-related changes in temporal sensitivity to increments in the inter-onset intervals (IOI) of successive components in tonal sequences. Temporal discrimination was examined using reference stimulus patterns consisting of five 50-ms, 4000-Hz components with equal tonal IOIs selected from the range 100-600 ms. Discrimination was examined in separate conditions by measuring the relative difference limen (DL) for increments of tonal IOI in comparison sequences. In some conditions, comparison sequences featured equal increments of all tonal lOIs to examined listener sensitivity to uniform changes of sequence rate, or tempo. Other conditions measured the DL for increments of a single target IOI within otherwise uniform-rate comparison sequences. For these measurements, the single target IOI was either fixed in sequence location, or randomized in location across listening trials. Listeners in the study included four groups of young and elderly adults with and without high-frequency hearing loss. The results for all listeners showed the relative DL for rate discrimination to decrease from a maximum at the 100-ms IOI to a smaller stable value across the range of longer sequence IOI. All listeners also exhibited larger relative DLs for discrimination of single target intervals compared to rate discrimination for equivalent reference IOI values. Older listeners showed poorer performance than younger listeners in all conditions, with the largest age differences observed for discrimination of brief single intervals that were varied randomly in sequence location. None of the results revealed significant effects of hearing loss on performance of younger and older listeners.

Adult↗

PubMed2000

Frequency and temporal resolution in elderly listeners with good and poor word recognition.

There is a subgroup of elderly listeners with hearing loss who can be characterized by exceptionally poor speech understanding. This study examined the hypothesis that the poor speech-understanding performance of some elderly listeners is associated with disproportionate deficits in temporal resolution and frequency resolution, especially for complex signals. Temporal resolution, as measured by gap detection, and frequency resolution, as measured by the critical ratio, were examined in older listeners with normal hearing, older listeners with hearing loss and good speech-recognition performance, and older listeners with hearing loss and poor speech-recognition performance. Listener performance was evaluated for simple and complex stimuli and for tasks of added complexity. In addition, syllable recognition was assessed in quiet and noise. The principal findings were that older listeners with hearing loss and poor word-recognition performance did not perform differently from older listeners with hearing loss and good word recognition on the temporal resolution measures nor on the spectral resolution measures for relatively simple stimuli. However, frequency resolution was compromised for listeners with poor word-recognition abilities when targets were presented in the context of complex signals. Group differences observed for syllable recognition in quiet were eliminated in the noise condition. Taken together, the findings support the hypothesis that unusual deficits in word-recognition performance among elderly listeners were associated with poor spectral resolution for complex signals.

Aged↗

PubMed1999

Profile of auditory temporal processing in older listeners.

This investigation examined age-related performance differences on a range of speech and nonspeech measures involving temporal manipulation of acoustic signals and variation of stimulus complexity. The goal was to identify a subset of temporally mediated measures that effectively distinguishes the performance patterns of younger and older listeners, with and without hearing loss. The nonspeech measures included duration discrimination for simple tones and gaps, duration discrimination for tones and gaps embedded within complex sequences, and discrimination of temporal order. The speech measures were undistorted speech, time-compressed speech, reverberant speech, and combined time-compressed + reverberant speech. All speech measures were presented both in quiet and in noise. Strong age effects were observed for the nonspeech measures, particularly in the more complex stimulus conditions. Additionally, age effects were observed for all time-compressed speech conditions and some reverberant speech conditions, in both quiet and noise. Effects of hearing loss were observed also for the speech measures only. Discriminant function analysis derived a formula, based on a subset of these measures, for classifying individuals according to temporal performance consistent with age and hearing loss categories. The most important measures to accomplish this goal involved conditions featuring temporal manipulations of complex speech and nonspeech signals.

Adolescent↗

PubMed1998

Auditory temporal order perception in younger and older adults.

This investigation examined the abilities of younger and older listeners to discriminate and identify temporal order of sounds presented in tonal sequences. It was hypothesized that older listeners would exhibit greater difficulty than younger listeners on both temporal processing tasks, particularly for complex stimulus patterns. It was also anticipated that tone order discrimination would be easier than tone order identification for all listeners. Listeners were younger and older adults with either normal hearing or mild-to-moderate sensorineural hearing losses. Stimuli were temporally contiguous three-tone sequences within a 1/3 octave frequency range centered at 4000 Hz. For the discrimination task, listeners discerned differences between standard and comparison stimulus sequences that varied in tonal temporal order. For the identification task, listeners identified tone order of a single sequence using labels of relative pitch. Older listeners performed more poorly than younger listeners on the discrimination task for the more complex pitch patterns and on the identification task for faster stimulus presentation rates. The results also showed that order discrimination is easier than order identification for all listeners. The effects of hearing loss on the ordering tasks were minimal.

Adolescent↗

PubMed1997

Construction of hearing percentiles in women with non-constant variance from the linear mixed-effects model.

Current age-specific reference standards for adult hearing thresholds are primarily cross-sectional in nature and vary in the degree of screening of the reference sample for noise-induced hearing loss and other hearing problems. We develop methods to construct age-specific percentiles for longitudinal data that have been modelled using the linear mixed-effects model. We apply these methods to construct percentiles of hearing level using data from a carefully screened sample of women from the Baltimore Longitudinal Study of Aging. However, the variation in the residuals and random effects from the linear mixed-effects model does not remain constant with age and frequency of the stimulus tone. In addition, the distribution of the hearing levels is not symmetric about the mean. We develop a number of methods to use the output from the linear mixed-effects model to construct percentiles that do not have constant variance. We use a transformation of the hearing levels to provide for skewness in the final percentile curves. The change in the variation of the residuals and random effects is modelled as a function of beginning age and frequency and we use this variance function to construct the hearing percentiles. We present a number of approaches. First, we use the absolute values of the population residuals to model the total deviation about the mean as a function of beginning age and frequency. Second, we model the standard deviation in the person-specific (cluster) residuals as well as the standard deviation in the estimated random effects. Finally, we use weighted least squares with the regressions on the absolute cluster residuals and absolute estimated random effects where the weights are the reciprocal of the standard deviations of their estimates.

Adolescent↗

PubMed1997

Selected cognitive factors and speech recognition performance among young and elderly listeners.

The influence of selected cognitive factors on age-related changes in speech recognition was examined by measuring the effects of recall task, speech rate, and availability of contextual cues on recognition performance by young and elderly listeners. Stimuli were low and high context sentences from the R-SPIN test presented at normal and slowed speech rates in noise. Response modes were final word recall and sentence recall. The effects of hearing loss and age were examined by comparing performances of young and elderly listeners with normal hearing and young and elderly listeners with hearing loss. Listeners with hearing loss performed more poorly than listeners with normal hearing in nearly every condition. In addition, elderly listeners exhibited poorer performance than younger listeners on the sentence recall task, but not on the word recall task, indicating that added memory demands have a detrimental effect on elderly listeners' performance. Slowing of speech rate did not have a differential effect on performance of young and elderly listeners. All listeners performed well when stimulus contextual cues were available. Taken together, these results support the notion that the performance of elderly listeners with hearing loss is influenced by a combination of auditory processing factors, memory demands, and speech contextual information.

Adolescent↗

PubMed1996

Age- and gender-specific reference ranges for hearing level and longitudinal changes in hearing level.

This paper presents age-specific reference ranges for hearing level and change in hearing level for men and women at 500, 1000, 2000, and 4000 Hz. The percentiles are constructed from data obtained from persons in the Baltimore Longitudinal Study of Aging who were rigorously screened for otological disorders and evidence of noise-induced hearing loss. The resulting percentile curves represent norms for changes in hearing level in the absence of any known otologic disease. These percentile curves provide a reference for detecting when a person deviates from a normal pattern of change, thus helping in diagnosing problems with hearing or in monitoring hearing in occupational settings. The smoothed means and standard deviations of the hearing levels were used to construct the longitudinal percentiles. The percentiles for cross-sectional change were constructed using the skew normal distribution to allow for the percentiles to be asymmetric on either side of the median level. These percentiles are the first reference curves that (1) provide standards for hearing level changes over periods of up to 15 years, (2) account for age differences in the distribution of hearing levels, and (3) are based on data from persons who have been systematically screened for otological disorders and evidence of noise-induced hearing loss.

Adult↗

PubMed1996

Risk factors related to age-associated hearing loss in the speech frequencies.

This paper examines the relationship between several risk factors and the development of age-associated hearing loss in the speech frequencies. Hearing loss is defined as an average threshold level of 30 dB HL or greater at the frequencies of 0.5, 1, 2, and 3 kHz. Hearing thresholds from 0.5 to 8 kHz using a pulse-tone tracking procedure were collected on participants of the Baltimore Longitudinal study of Aging since 1965. A proportional hazards regression model was used to study the relationship between several risk factors that have previously been found to be associated with numerous health-related outcomes and the length of follow-up time until the occurrence of unilateral or bilateral hearing loss in a screened group of 531 men. Risk factors considered are age, blood pressure, and alcohol and cigarette consumption. After controlling for age, only systolic blood pressure showed a significant relationship with hearing loss in the speech frequencies (p < .05). Since blood pressure is a modifiable risk factor, these results suggest that preventing hypertension might contribute to an effective program for the prevention of apparent age-associated hearing loss.

Adult↗

PubMed1996

Auditory temporal processing in elderly listeners.

This paper examines the hypothesis that auditory temporal processing is impaired in elderly listeners. Several recent psychoacoustic studies are reviewed that describe various aspects of temporal processing that appear to be influenced by aging. The temporal phenomena range from measures of temporal resolution and duration discrimination to sequential processing of complex stimulus patterns. For many of the research findings, age-related deficits on temporal performance measures are unaffected by the presence of presbyacusic hearing loss. Additionally, the consequences of aging on auditory temporal processing appear to be correlated with the complexity of stimulation and the difficulty of the listening tasks.

Adult↗

PubMed1995

Accuracy of speech intelligibility index predictions for noise-masked young listeners with normal hearing and for elderly listeners with hearing impairment.

This study examined whether the accuracy of Speech Intelligibility Index (SII) predictions is affected by subject age when between-groups auditory sensitivity differences are controlled. SII predictive accuracy was assessed for elderly listeners with hearing impairment (EHI) and for young noise-masked listeners with normal hearing (NMN). SII predictive accuracy was poorer for the EHI subjects than for the NMN subjects across a range of test conditions and stimuli. Speech test redundancy, speech presentation level, signal-to-babble ratio, and babble level also affected SII predictive accuracy. The results suggest that the speech recognition difficulties experienced in noise by elderly listeners do not result solely from reduced auditory sensitivity.

Adult↗

PubMed1995

Comparing recognition of distorted speech using an equivalent signal-to-noise ratio index.

An index of equivalent performance in noise was developed to compare recognition in different forms of speech distortion. Speech-recognition performance of young and elderly listeners with and without hearing loss was evaluated for undistorted speech presented in quiet and noise, and for speech distorted by four time-compression ratios and by four reverberation times. The data obtained in noise on young subjects with normal hearing served to generate a normalized regression equation, which was used to convert percent-correct performance in different distortion conditions to equivalent performance for undistorted speech at a particular S/N ratio. Comparisons of the equivalent S/N ratios obtained in the various conditions allowed rank-ordering of speech recognition performance in different types of degradation. The data also show that age and hearing loss affect recognition of speech degraded by reverberation or time compression. However, age effects are evident primarily in the most severe distortion conditions. Recognition of undistorted speech in noise was affected by hearing loss but not by age. These findings support a hypothesis that stipulates that increased age produces a reduction in the functional S/N ratio.

Adolescent↗

PubMed1995

Recognition of multiply degraded speech by young and elderly listeners.

This study investigated the hypothesis that age effects exert an increased influence on speech recognition performance as the number of acoustic degradations of the speech signal increases. Four groups participated: young listeners with normal hearing, elderly listeners with normal hearing, young listeners with hearing loss, and elderly listeners with hearing loss. Recognition was assessed for sentence materials degraded by noise, reverberation, or time compression, either in isolation or in binary combinations. Performance scores were converted to an equivalent signal-to-noise ratio index to facilitate direct comparison of the effects of different forms of stimulus degradation. Age effects were observed primarily in multiple degradation conditions featuring time compression of the stimuli. These results are discussed in terms of a postulated change in functional signal-to-noise ratio with increasing age.

Adolescent↗

PubMed1995

Gender differences in a longitudinal study of age-associated hearing loss.

Current studies are inconclusive regarding specific patterns of gender differences in age-associated hearing loss. This paper presents results from the largest and longest longitudinal study reported to date of changes in pure-tone hearing thresholds in men and women screened for otological disorders and noise-induced hearing loss. Since 1965, the Baltimore Longitudinal Study of Aging has collected hearing thresholds from 500 to 8000 Hz using a pulsed-tone tracking procedure. Mixed-effects regression models were used to estimate longitudinal patterns of change in hearing thresholds in 681 men and 416 women with no evidence of otological disease, unilateral hearing loss, or noise-induced hearing loss. The results show (1) hearing sensitivity declines more than twice as fast in men as in women at most ages and frequencies, (2) longitudinal declines in hearing sensitivity are detectable at all frequencies among men by age 30, but the age of onset of decline is later in women at most frequencies and varies by frequency in women, (3) women have more sensitive hearing than men at frequencies above 1000 Hz but men have more sensitive hearing than women at lower frequencies, (4) learning effects bias cross-sectional and short-term longitudinal studies, and (5) hearing levels and longitudinal patterns of change are highly variable, even in this highly selected group. These longitudinal findings document gender differences in hearing levels and show that age-associated hearing loss occurs even in a group with relatively low-noise occupations and with no evidence of noise-induced hearing loss.

Adult↗

PubMed1995

Age effects on duration discrimination with simple and complex stimuli.

This study examined age-related changes in temporal processing by measuring DLs for signal duration using simple and complex stimuli. Previous research has shown that elderly listeners exhibit difficulty discriminating duration changes in simple sounds, suggesting the possibility of age-related changes in central timing mechanisms. The present experiments examined the interactive effects of aging, hearing loss, and stimulus complexity on duration discrimination. Four groups participated: young and elderly listeners with normal hearing, and young and elderly listeners with hearing loss. Duration DLs were measured for 250-ms tone bursts and for silent gaps between tone bursts that were presented either in isolation or embedded as target stimuli within tonal sequences. The tone sequences were composed of five sequential 250-ms components. Stimulus complexity was varied by changing the sequential order of tone frequencies and the location of an embedded target component across listening conditions. Analyses of results revealed the following: Elderly listeners performed more poorly than younger listeners in nearly all stimulus conditions, the effects of stimulus complexity on discrimination were greatest among elderly listeners, and hearing loss had no systematic effect on discrimination performance.

Adult↗

PubMed1994

Age effects on measures of auditory duration discrimination.

This study examined auditory temporal sensitivity in young adult and elderly listeners using psychophysical tasks that measured duration discrimination. Listeners in the experiments were divided into groups of young and elderly subjects with normal hearing sensitivity and with mild-to-moderate sloping sensorineural hearing loss. Temporal thresholds in all tasks were measured with an adaptive forced-choice procedure using tonal stimuli centered at 500 Hz and 4000 Hz. Difference limens for duration were measured for tone bursts (250 msec reference duration) and for silent intervals between tone bursts (250 msec and 6.4 msec reference durations). Results showed that the elderly listeners exhibited diminished duration discrimination for both tones and silent intervals when the reference duration was 250 msec. Hearing loss did not affect these results. Discrimination of the brief temporal gap (6.4 msec) was influenced by age and hearing loss, but these effects were not consistent across all listeners. Effects of stimulus frequency were not evident for most of the duration discrimination conditions.

Adult↗

PubMed1994

Age effects on measures of hearing disability.

This study investigated the effects of age on self-perceived hearing disability among young and elderly people with comparable hearing sensitivity. Subjects were young (18-40 yr) and elderly (65-75 yr) listeners with either normal hearing sensitivity or mild-to-moderate sloping sensorineural hearing loss. The Hearing Handicap Inventory for the Elderly was presented to the older subjects and the Hearing Handicap Inventory for Adults was presented to the younger subjects. Statistical analyses revealed an interaction between age and hearing loss, in which younger subjects with hearing loss reported more handicapping effects of sensitivity loss than the elderly subjects with hearing loss. This age effect was not attributed to differences in hearing sensitivity between the young and elderly subjects with hearing impairment.

Adult↗

PubMed1994

Auditory duration discrimination in young and elderly listeners with normal hearing.

This study investigated the effects of age on two parameters of auditory temporal processing: auditory duration discrimination and the backward interference of auditory duration discrimination. Young and elderly listeners with normal hearing sensitivity participated. In experiment I, the just-noticeable difference (JND) in duration between a standard 1000-Hz tone of 40 msec and a comparison tone of longer duration was evaluated using a three-interval forced-choice task. In experiment II, the duration discrimination paradigm was presented with a tonal masker following the tonal stimulus at three delay times: 80 msec, 240 msec, and 720 msec. Age effects were observed on the duration discrimination task with interference but not on the initial duration discrimination task without interference. These results suggest that the time required to process the duration characteristics of acoustic stimuli is prolonged in elderly listeners.

Adolescent↗