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Frequency modulation (FM) detection at low modulation frequencies is commonly used as an index of temporal fine-structure processing. The present study evaluated the rate of improvement in monaural and dichotic FM across a range of test parameters. In experiment I, dichotic and monaural FM detection was measured as a function of duration and modulator starting phase. Dichotic FM thresholds were lower than monaural FM thresholds and the modulator starting phase had no effect on detection. Experiment II measured monaural FM detection for signals that differed in modulation rate and duration such that the improvement with duration in seconds (carrier) or cycles (modulator) was compared. Monaural FM detection improved monotonically with the number of modulation cycles, suggesting that the modulator is extracted prior to detection. Experiment III measured dichotic FM detection for shorter signal durations to test the hypothesis that dichotic FM relies primarily on the signal onset. The rate of improvement decreased as duration increased, which is consistent with the use of primarily onset cues for the detection of dichotic FM. These results establish that improvement with duration occurs as a function of the modulation cycles at a rate consistent with the independent-samples model for monaural FM, but later cycles contribute less to detection in dichotic FM. [ABSTRACT FROM AUTHOR]

Objective: The present study was motivated by a need for a speech intelligibility test capable of indexing dynamic changes in the environment and adaptive processing in hearing aids. The Continuous Number Identification Test (CNIT) was developed to meet these aims. Design: From one location in the free field, speech was presented in noise (∼2 words/s) with a 100-ms inter-word interval. On average, every fourth word was a target digit and all other words were monosyllabic words. Non-numeric words had a fixed presentation level such that the dominant signal-to-noise-ratio (SNR) was held at +6 dB SNR relative to background maskers. To prevent ceiling effects, however, targets were presented at a user-specific SNR, determined by an initial adaptive-tracking procedure that estimated the 79.4% speech reception threshold. Study sample: Ten normal-hearing listeners participated. Results: The CNIT showed comparable psychometric qualities of other established speech tests for long time scales (Exp. 1). Target-location changes did not affect performance on the CNIT (Exp. 2), but the test did show high temporal resolution in assessing sudden changes to SNR (Exp. 3). Conclusions: The CNIT is highly customisable, and the initial experiments tested feasibility of its primary features which set it apart from currently available speech-in-noise tests. [ABSTRACT FROM AUTHOR]

Purpose: Growing evidence supports the inclusion of perceptual tests that quantify the processing of temporal fine structure (TFS) in clinical hearing assessment. Many tasks have been used to evaluate TFS in the laboratory that vary greatly in the stimuli used and whether the judgments require monaural or binaural comparisons of TFS. The purpose of this study was to compare laboratory measures of TFS for inclusion in a battery of suprathreshold auditory tests. A subset of available TFS tasks were selected on the basis of potential clinical utility and were evaluated using metrics that focus on characteristics important for clinical use. Method: TFS measures were implemented in replication of studies that demonstrated clinical utility. Monaural, diotic, and dichotic measures were evaluated in 11 young listeners with normal hearing. Measures included frequency modulation (FM) tasks, harmonic frequency shift detection, interaural phase difference (TFS-low frequency), interaural time difference (ITD), monaural gap duration discrimination, and Purpose: Growing evidence supports the inclusion of perceptual tests that quantify the processing of temporal fine structure (TFS) in clinical hearing assessment. Many tasks have been used to evaluate TFS in the laboratory that vary greatly in the stimuli used and whether the judgments require monaural or binaural comparisons of TFS. The purpose of this study was to compare laboratory measures of TFS for inclusion in a battery of suprathreshold auditory tests. A subset of available TFS tasks were selected on the basis of potential clinical utility and were evaluated using metrics that focus on characteristics important for clinical use. Method: TFS measures were implemented in replication of studies that demonstrated clinical utility. Monaural, diotic, and dichotic measures were evaluated in 11 young listeners with normal hearing. Measures included frequency modulation (FM) tasks, harmonic frequency shift detection, interaural phase difference (TFS-low frequency), interaural time difference (ITD), monaural gap duration discrimination, and [ABSTRACT FROM AUTHOR]

Background: Severe hearing loss impairs communication in a wide range of listening environments. However, we lack data as to the specific objective and subjective abilities of listeners with severe hearing loss. Insight into those abilities may inform treatment choices. Purpose: The primary goal was to describe the audiometric profiles, spectral resolution ability, and objective and subjective speech perception of a sample of adult listeners with severe hearing loss, and to consider the relationships among those measures. We also considered the typical fitting received by individuals with severe loss, in terms of hearing aid style, electroacoustic characteristics, and features, as well as supplementary device use. Research Design: A within-subjects design was used. Study Sample: Participants included 36 adults aged 54-93 yr with unilateral or bilateral severe hearing loss. Data Collection and Analysis: Testing included a full hearing and hearing aid history; audiometric evaluation; loudness growth and dynamic range; spectral resolution; assessment of cochlear dead regions; objective and subjective assessment of speech recognition; and electroacoustic evaluation of current hearing aids. Regression models were used to analyze relationships between hearing loss, spectral resolution, and speech recognition. Results: For speech in quiet, 60% of the variance was approximately equally accounted for by amount of hearing loss, spectral resolution, and number of dead regions. For speech in noise, only a modest proportion of performance variance was explained by amount of hearing loss. In general, participants were wearing amplification of appropriate style and technology for their hearing loss, but the extent of assistive technology use was low. Subjective communication ratings depended on the listening situation, but in general, were similar to previously published data for adults with mild-to-moderate loss who did not wear hearing aids. Conclusions: The present data suggest that the range of abilities of an individual can be more fully captured with comprehensive testing. Such testing also offers an opportunity for informed counseling regarding realistic expectations for hearing aid use and the availability of hearing assistive technology. [ABSTRACT FROM AUTHOR]

Spectral modulation transfer functions (SMTFs) were measured in 49 young (18–35 years of age) normal-hearing listeners. Noise carriers spanned six octaves from 200 to 12 800 Hz. Sinusoidal (on a log-amplitude scale) spectral modulation with random starting phase was superimposed on the carrier at spectral modulation frequencies of 0.25, 0.5, 1.0, 2.0, 4.0, and 8.0 cycles/octave. Modulation detection thresholds (in dB) yielded SMTFs that were bandpass in nature, consistent with previous investigations reporting data for only a few subjects. Thresholds were notably consistent across subjects despite minimal practice. Population statistics are reported that may serve as reference data for future studies. [ABSTRACT FROM AUTHOR]

Background: Auditory complaints following mild traumatic brain injury (MTBI) are common, but few studies have addressed the role of auditory temporal processing in speech recognition complaints. Purpose: In this study, deficits understanding speech in a background of speech noise following MTBI were evaluated with the goal of comparing the relative contributions of auditory and nonauditory factors. Research Design: A matched-groups design was used in which a group of listeners with a history of MTBI were compared to a group matched in age and pure-tone thresholds, as well as a control group of young listeners with normal hearing (YNH). Study Sample: Of the 33 listeners who participated in the study, 13 were included in the MTBI group (mean age = 46.7 yr), 11 in the Matched group (mean age = 49 yr), and 9 in the YNH group (mean age = 20.8 yr). Data Collection and Analysis: Speech-in-noise deficits were evaluated using subjective measures as well as monaural word (Words-in-Noise test) and sentence (Quick Speech-in-Noise test) tasks, and a binaural spatial release task. Performance on these measures was compared to psychophysical tasks that evaluate monaural and binaural temporal fine-structure tasks and spectral resolution. Cognitive measures of attention, processing speed, and working memory were evaluated as possible causes of differences between MTBI and Matched groups that might contribute to speech-in-noise perception deficits. Results: A high proportion of listeners in the MTBI group reported difficulty understanding speech in noise (84%) compared to the Matched group (9.1%), and listeners who reported difficulty were more likely to have abnormal results on objective measures of speech in noise. No significant group differences were found between the MTBI and Matched listeners on any of the measures reported, but the number of abnormal tests differed across groups. Regression analysis revealed that a combination of auditory and auditory processing factors contributed to monaural speech-in-noise scores, but the benefit of spatial separation was related to a combination of working memory and peripheral auditory factors across all listeners in the study. Conclusions: The results of this study are consistent with previous findings that a subset of listeners with MTBI has objective auditory deficits. Speech-in-noise performance was related to a combination of auditory and nonauditory factors, confirming the important role of audiology in MTBI rehabilitation. Further research is needed to evaluate the prevalence and causal relationship of auditory deficits following MTBI. [ABSTRACT FROM AUTHOR]

Background: In ice hockey players, serious bone injuries in the foot and ankle, especially those attributed to impact from the moving puck, may be radiographically occult and underrecognized. Purpose/Hypothesis: The purpose of this research was to study foot and ankle bone injuries detected with magnetic resonance imaging (MRI) that occurred in elite hockey players. The hypothesis was that these injuries predominate medially, especially when caused by the impact from the puck, and are associated with prolonged lost playing time. Study Design: Case series; Level of evidence, 4. Methods: Three independent observers, blinded to the mechanism of injury, retrospectively reviewed foot and ankle MRI examinations acquired after 31 acute injuries that occurred in 27 elite ice hockey players who had no radiographically visible fractures. Bone abnormalities were classified as fractures or varying degrees of contusion based on predetermined definitions. Interobserver agreement was analyzed with kappa statistics. The association between the injury mechanism and the bones involved was examined with the Fisher exact test. A t test was applied to determine if MRI evidence of a severe bone injury (defined as either a fracture or a high-grade bone contusion) was associated with longer recovery times, when return-to-play information was available. Results: The observers identified at least 1 bone injury in 27 of the 31 MRI examinations, including 10 with radiographically occult fractures. Agreement among the 3 observers for injury categorization was substantial (κ = 0.76). Seventeen injuries were caused by a direct blow (15 from a moving puck, 2 from an uncertain source), resulting in 6 fractures and 6 high-grade bone contusions, with 14 of the 17 involving a medial bone (medial malleolus, navicular, or first metatarsal base). Compared with other mechanisms, direct impaction was statistically more likely to result in a severe bone injury and to involve the medial foot and ankle. In 20 injuries where return-to-play information was available, players with severe bone injuries missed a mean of 10.6 games compared with 2.4 games for other players (P = .05). Conclusion: MRI can show severe bone injuries that are not visible radiographically in ice hockey players. Most fractures and high-grade contusions involve the medial ankle and midfoot bones, can be caused by direct blows from the puck, and are associated with prolonged recovery times. [ABSTRACT FROM AUTHOR]

Background: Temporal resolution is important for speech recognition and may contribute to variability in speech recognition among patients. Clinical tests of temporal resolution are available, but It is not clear how closely results of those tests correspond to results of traditional temporal resolution tests. Purpose: The purpose of this study was to compare the Gaps-in-Noise (GIN) test to a traditional measure of gap detection. Study Sample: This study included older adults with hearing loss and younger adults with normal hearing. Data Collection and Analysis: Participants completed one practice and two test blocks of each gap detection test, and a measure of speech-in-noise recognition. Individual data were correlated to examine the relationship between the tests. Results: The GIN and traditional gap detection were significantly, but not highly correlated. The traditional gap detection test contributed to variance in speech recognition in noise, while the GIN did not. Conclusions: The brevity and ease of implementing the GIN in the clinic make it a viable test of temporal resolution. However, it differs from traditional measures in implementation, and as a result relies on different cognitive factors. The GIN thresholds should be interpreted carefully and not presumed to represent an approximation of traditional gap detection thresholds. [ABSTRACT FROM AUTHOR]

Purpose: The benefits of amplitude compression in hearing aids may be limited by distortion resulting from rapid gain adjustment. To evaluate this, it is convenient to quantify distortion by using a metric that is sensitive to the changes in the processed signal that decrease consonant recognition, such as the Envelope Difference Index (EDI; Fortune, Woodruff, & Preves, 1994). However, the EDI relies on the entire duration of the signal, including portions irrelevant to consonant recognition. Method: This note describes a computationally efficient method of automatically segmenting speech in time according to the syllable structure. Our technique uses the 1st derivative of the envelope as a basis. Peaks located in the derivative were used to generate a weighting function for the computation of a metric of signal distortion. Results: The weighting function significantly improved the variance explained in consonant recognition scores over previous methods. However, only 3.2% of the variance was explained in the revised model. Conclusion: This technique was effective in focusing the analysis of distortion on specific segments of the signal. Use of the technique has implications for speech analysis. The difference in the amplitude envelope of consonants is not a robust model of the effect of hearing aid compression on consonant recognition. [ABSTRACT FROM AUTHOR]

Purpose: The benefits of amplitude compression in hearing aids may be limited by distortion resulting from rapid gain adjustment. To evaluate this, it is convenient to quantify distortion by using a metric that is sensitive to the changes in the processed signal that decrease consonant recognition, such as the Envelope Difference Index (EDI; Fortune, Woodruff, & Preves, 1994). However, the EDI relies on the entire duration of the signal, including portions irrelevant to consonant recognition. Method: This note describes a computationally efficient method of automatically segmenting speech in time according to the syllable structure. Our technique uses the 1st derivative of the envelope as a basis. Peaks located in the derivative were used to generate a weighting function for the computation of a metric of signal distortion. Results: The weighting function significantly improved the variance explained in consonant recognition scores over previous methods. However, only 3.2% of the variance was explained in the revised model. Conclusion: This technique was effective in focusing the analysis of distortion on specific segments of the signal. Use of the technique has implications for speech analysis. The difference in the amplitude envelope of consonants is not a robust model of the effect of hearing aid compression on consonant recognition. [ABSTRACT FROM AUTHOR]

Purpose: Amplitude compression is a common hearing aid processing strategy that can improve speech audibility and loudness comfort but also has the potential to alter important cues carried by the speech envelope. In previous work, a measure of envelope change, the Envelope Difference Index (EDI; Fortune, Woodruff, & Preves, 1994), was moderately related to recognition of spectrally robust consonants. This follow-up study investigated the relationship between the EDI and recognition of spectrally sparse consonants. Method: Stimuli were vowel-consonant-vowel tokens processed to reduce spectral cues. Compression parameters were chosen to achieve a range of EDI values. Recognition was measured for 20 listeners with normal hearing. Results: Both overall recognition and perception of consonant features were reduced at higher EDI values. Similar effects were noted with noise-vocoded and sine-vocoded processing and regardless of whether periodicity cues were available. Conclusion: The data provide information about the acceptable limits of envelope distortion under constrained conditions. These limits can be used to consider the impact of envelope distortions in situations where other cues are available to varying extents. [ABSTRACT FROM AUTHOR]

Purpose: Amplitude compression is a common hearing aid processing strategy that can improve speech audibility and loudness comfort but also has the potential to alter important cues carried by the speech envelope. In previous work, a measure of envelope change, the Envelope Difference Index (EDI; Fortune, Woodruff, & Preves, 1994), was moderately related to recognition of spectrally robust consonants. This follow-up study investigated the relationship between the EDI and recognition of spectrally sparse consonants. Method: Stimuli were vowel-consonant-vowel tokens processed to reduce spectral cues. Compression parameters were chosen to achieve a range of EDI values. Recognition was measured for 20 listeners with normal hearing. Results: Both overall recognition and perception of consonant features were reduced at higher EDI values. Similar effects were noted with noise-vocoded and sine-vocoded processing and regardless of whether periodicity cues were available. Conclusion: The data provide information about the acceptable limits of envelope distortion under constrained conditions. These limits can be used to consider the impact of envelope distortions in situations where other cues are available to varying extents. [ABSTRACT FROM AUTHOR]

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