Publications by authors named "Michael Kiefte"

The need for objective measurement in psychiatry has stimulated interest in alternative indicators of the presence and severity of illness. Speech may offer a source of information that bridges the subjective and objective in the assessment of mental disorders. We systematically reviewed the literature for articles exploring speech analysis for psychiatric applications.

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Although the first two or three formant frequencies are considered essential cues for vowel identification, certain limitations of this approach have been noted. Alternative explanations have suggested listeners rely on other aspects of the gross spectral shape. A study conducted by Ito, Tsuchida, and Yano [(2001).

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Natural sounds have substantial acoustic structure (predictability, nonrandomness) in their spectral and temporal compositions. Listeners are expected to exploit this structure to distinguish simultaneous sound sources; however, previous studies confounded acoustic structure and listening experience. Here, sensitivity to acoustic structure in novel sounds was measured in discrimination and identification tasks.

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Given recent interest in the analysis of naturally produced spontaneous speech, a large database of speech samples from the Canadian Maritimes was collected, processed, and analyzed with the primary aim of examining vowel-inherent spectral change in formant trajectories. Although it takes few resources to collect a large sample of audio recordings, the analysis of spontaneous speech introduces a number of difficulties compared to that of laboratory citation speech: Surrounding consonants may have a large influence on vowel formant frequencies and the distribution of consonant contexts is highly unbalanced. To overcome these problems, a statistical procedure inspired by that of Broad and Clermont [(2014).

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Purpose: Speech-in-noise testing relies on a number of factors beyond the auditory system, such as cognitive function, compliance, and motor function. It may be possible to avoid these limitations by using electroencephalography. The present study explored this possibility using the N400.

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Some evidence, mostly drawn from experiments using only a single moderate rate of speech, suggests that low-frequency amplitude modulations may be particularly important for intelligibility. Here, two experiments investigated intelligibility of temporally distorted sentences across a wide range of simulated speaking rates, and two metrics were used to predict results. Sentence intelligibility was assessed when successive segments of fixed duration were temporally reversed (exp.

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Although recent evidence reconfirmed the importance of spectral peak frequencies in vowel identification [Kiefte and Kluender (2005). J. Acoust.

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Brief experience with reliable spectral characteristics of a listening context can markedly alter perception of subsequent speech sounds, and parallels have been drawn between auditory compensation for listening context and visual color constancy. In order to better evaluate such an analogy, the generality of acoustic context effects for sounds with spectral-temporal compositions distinct from speech was investigated. Listeners identified nonspeech sounds-extensively edited samples produced by a French horn and a tenor saxophone-following either resynthesized speech or a short passage of music.

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Objectives: (1) To determine whether high-frequency sensorineural hearing loss (HF SNHL) is accompanied by deterioration in temporal resolution in the low-frequency region where hearing sensitivity is within normal range. (2) To evaluate whether such temporal processing deficits contribute to speech perception difficulty in noise.

Design: A between-group design was employed, using subjects either with or without high-frequency hearing loss and matched by age.

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Unlabelled: The effects of SpeechEasy on stuttering frequency, stuttering severity self-ratings, speech rate, and speech naturalness for 31 adults who stutter were examined. Speech measures were compared for samples obtained with and without the device in place in a dispensing setting. Mean stuttering frequencies were reduced by 79% and 61% for the device compared to the control conditions on reading and monologue tasks, respectively.

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Unlabelled: A multiple single-subject design was used to examine the effects of SpeechEasy on stuttering frequency in the laboratory and in longitudinal samples of speech produced in situations of daily living (SDL). Seven adults who stutter participated, all of whom had exhibited at least 30% reduction in stuttering frequency while using SpeechEasy during previous laboratory assessments. For each participant, speech samples recorded in the laboratory and SDL during device use were compared to samples obtained in those settings without the device.

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Several experiments are described in which synthetic monophthongs from series varying between /i/ and /u/ are presented following filtered precursors. In addition to F(2), target stimuli vary in spectral tilt by applying a filter that either raises or lowers the amplitudes of higher formants. Previous studies have shown that both of these spectral properties contribute to identification of these stimuli in isolation.

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Unlabelled: The effects of choral speech and altered auditory feedback (AAF) on stuttering frequency were compared to identify those properties of choral speech that make it a more effective condition for stuttering reduction. Seventeen adults who stutter (AWS) participated in an experiment consisting of special choral speech conditions that were manipulated to selectively eliminate specific differences between choral speech and AAF. Consistent with previous findings, results showed that both choral speech and AAF reduced stuttering compared to solo reading.

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Unlabelled: The effect of SpeechEasy on stuttering frequency during speech produced in a laboratory setting was examined. Thirteen adults who stutter participated. Stuttering frequencies in two baseline conditions were compared to stuttering frequencies with the device fitted according to the manufacturer's protocol.

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Among the most influential publications in speech perception is Liberman, Delattre, and Cooper's [Am. J. Phys.

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Hypothesis: Ossiculoplasty using prosthetic reconstruction with a malleus assembly to the stapes head will result in better transmission of vibrations from the eardrum to the stapes footplate than reconstruction with a tympanic membrane assembly to the stapes head. Both types of reconstruction will be affected by tension of the prosthesis.

Background: Theories (and some clinical studies) that the shape of the normal tympanic membrane is important suggest that prosthetic reconstruction to the malleus performs better than reconstruction to the tympanic membrane.

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Objective: Hearing results from ossiculoplasty are unpredictable. There are many potentially modifiable parameters. One parameter that has not been adequately investigated in the past is the effect of tension on the mechanical functioning of the prosthesis.

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Perceptual systems in all modalities are predominantly sensitive to stimulus change, and many examples of perceptual systems responding to change can be portrayed as instances of enhancing contrast. Multiple findings from perception experiments serve as evidence for spectral contrast explaining fundamental aspects of perception of coarticulated speech, and these findings are consistent with a broad array of known psychoacoustic and neurophysiological phenomena. Beyond coarticulation, important characteristics of speech perception that extend across broader spectral and temporal ranges may best be accounted for by the constant calibration of perceptual systems to maximize sensitivity to change.

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Previous studies of auditory-nerve fiber (ANF) representation of vowels in cats and rodents (chinchillas and guinea pigs) have shown that, at amplitudes typical for conversational speech (60-70 dB), neuronal firing rate as a function of characteristic frequency alone provides a poor representation of spectral prominences (e.g., formants) of speech sounds.

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