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PubMed2001

Segmentation of the speech stream in a non-human primate: statistical learning in cotton-top tamarins.

Previous work has shown that human adults, children, and infants can rapidly compute sequential statistics from a stream of speech and then use these statistics to determine which syllable sequences form potential words. In the present paper we ask whether this ability reflects a mechanism unique to humans, or might be used by other species as well, to acquire serially organized patterns. In a series of four experimental conditions, we exposed a New World monkey, the cotton-top tamarin (Saguinus oedipus), to the same speech streams used by Saffran, Aslin, and Newport (Science 274 (1996) 1926) with human infants, and then tested their learning using similar methods to those used with infants. Like humans, tamarins showed clear evidence of discriminating between sequences of syllables that differed only in the frequency or probability with which they occurred in the input streams. These results suggest that both humans and non-human primates possess mechanisms capable of computing these particular aspects of serial order. Future work must now show where humans' (adults and infants) and non-human primates' abilities in these tasks diverge.

Adult↗
PubMed1999

Correlates of linguistic rhythm in the speech signal.

Spoken languages have been classified by linguists according to their rhythmic properties, and psycholinguists have relied on this classification to account for infants' capacity to discriminate languages. Although researchers have measured many speech signal properties, they have failed to identify reliable acoustic characteristics for language classes. This paper presents instrumental measurements based on a consonant/vowel segmentation for eight languages. The measurements suggest that intuitive rhythm types reflect specific phonological properties, which in turn are signaled by the acoustic/phonetic properties of speech. The data support the notion of rhythm classes and also allow the simulation of infant language discrimination, consistent with the hypothesis that newborns rely on a coarse segmentation of speech. A hypothesis is proposed regarding the role of rhythm perception in language acquisition.

Adult↗
PubMed1998

An algorithm for the automatic differentiation between the speech of normals and patients with Friedreich's ataxia based on the short-time fractal dimension.

In this paper, we describe an algorithm, based on acoustic pattern matching techniques, for providing an automatic, highly reliable distinction between normal and some kind of pathological speech (Friedreich's ataxia disease). For each utterance, the short-time fractal dimension parameter and, for comparison, the zero-crossing and energy ratio parameters are evaluated and used in the classification task by means of a dynamic programming procedure. Although all the parameters are able to differentiate the two groups, the fractal dimension parameter seems to provide a more reliable pattern classification than zero-crossing and energy ratio. Finally, we point out that, to the discrimination purpose, an accurate choice of the utterances to be pronounced by the subjects is to be considered.

Adult↗
PubMed2003

R-citalopram attenuates anxiolytic effects of escitalopram in a rat ultrasonic vocalisation model.

Escitalopram mediates the serotonin reuptake inhibitory effect of citalopram. To investigate the potential interactive effects between escitalopram and R-citalopram, they were studied at standard and elevated serotonin levels in a model predictive of anxiolytic activity (inhibition of footshock-induced ultrasonic vocalisation in adult rats). At standard levels, citalopram partially inhibited (64%) and escitalopram abolished (97%) vocalisation. Co-treatment with L-5-hydroxytryptophan resulted in complete inhibition with citalopram and a substantially enhanced response to escitalopram, while R-citalopram increased the vocalisation significantly. Furthermore, R-citalopram attenuated the effect of escitalopram. These findings may be relevant to the enhanced clinical efficacy seen with escitalopram compared to citalopram.

5-Hydroxytryptophan↗
PubMedDate not supplied

Second formant transitions in fluent speech of persistent and recovered preschool children who stutter.

UNLABELLED: This study investigated frequency change and duration of the second formant (F2) transitions in perceptually fluent speech samples recorded close to stuttering onset in preschool age children. Comparisons were made among 10 children known to eventually persist in stuttering, 10 who eventually recovered from stuttering, and 10 normally fluent controls. All were enrolled in the longitudinal Stuttering Research Project at the University of Illinois. Subjects fluently repeated standard experimental sentences. The same 36 perceptually fluent target segments (syllables embedded in words) from each subject's repeated sentences were analyzed. The syllables were divided into three phonetic categories based on their initial consonant: bilabial, alveolar, and velar placement. The frequency change and duration of F2 transitions were analyzed for each of the target CV segments. F2 transition onset and offset frequencies and their interval (duration) were measured for each utterance. Data indicate that near stuttering onset, children whose stuttering eventually persisted demonstrated significantly smaller frequency change than that of the recovered group. It is suggested that the F2 transitions should continue to be investigated as a possible predictor of stuttering pathways. LEARNING OUTCOMES: (1) Readers will learn about studies regarding second formant transition related to stuttering. (2) Readers will learn about differences between children who persist in stuttering and those who recover from stuttering. (3) Readers will learn about research concerned with early identification of risk criteria in persistent stuttering.

Child, Preschool↗
PubMedDate not supplied

Perceptual effects of a flattened fundamental frequency at the sentence level under different listening conditions.

UNLABELLED: The purpose of this series of experiments was to examine the effect of a flattened fundamental frequency (F0) contour on the intelligibility of sentence length material in different listening environments. Eight speakers of different genders and ages produced sentences from the Speech Perception in Noise Test (SPIN). Each utterance was subjected to a resynthesis technique that allowed flattening of the fundamental frequency while maintaining the timing and spectral characteristics of the utterances. To avoid learning effects two groups of listeners were chosen to complete word transcription and interval scaling tasks of the unmodified and flattened F0 utterances under different listening conditions (competing white noise or multi-speaker babble) to obtain measures of speech intelligibility. Results were that a flattened fundamental frequency contour negatively influences speech intelligibility regardless of the nature of the competing background noise. LEARNING OUTCOMES: (1) To appreciate the role fundamental frequency variation plays in speech intelligibility. (2) To understand the importance of considering environmental noise in clinical speech intelligibility testing.

Adult↗
PubMedDate not supplied

Effects of a pressure target on laryngeal airway resistance in children.

The purpose of this study was to determine the effects of an intraoral air pressure target on estimation of laryngeal airway resistance (LAR) in normal children. Ten children produced the syllable /pi/ (a) with self-determined normal loudness, (b) with increased loudness, and (c) at a predetermined intraoral air pressure level of 6.5 to 7.5 cm of water. The target pressure level was selected because it was expected to result in estimated subglottal pressures that were lower than those associated with self-determined loudness levels. Results indicated significant differences in estimated subglottal pressure among the three conditions. As expected, estimated subglottal pressures were highest during loud speech and lowest during the pressure target task. LAR values associated with normal loudness were similar to values previously reported for children. The use of the pressure target resulted in LAR values that were reduced by 31% from normal loudness. These resistance values, however, were still greater than those reported for adult speakers at similar subglottal pressure levels. The results are explained relative to preferred loudness levels and vocal tract size differences in children and adults. It is suggested that use of a pressure target during estimation of LAR in children may provide additional data that more accurately reflect the aerodynamic integrity of the larynx. Implications for clinical assessment are discussed.

Adult↗
PubMedDate not supplied

Voice onset time in Spanish-English bilinguals: early versus late learners of English.

Thirty-two Hispanic speakers of English were evenly divided into two groups based on whether or not their initial learning of English began prior to, or after the age of 12 years. Each group had an even number of males (16) and females (16). The subjects were recorded producing a protocol of 18 basic speech syllables. The first three repetitions (54 tokens) were chosen for analysis. The 1728 tokens were digitized and measured for voice onset time (VOT). Findings support the hypothesis that the VOT values of Hispanics speaking English differ according to whether initial learning of English began prior to or after the age of 12 years. An analysis of variance (ANOVA) found significant main effects of group, place, voice, and gender. Significant interactions were group by voice, and voice by gender.

Adolescent↗
PubMedDate not supplied

Voice onset time in speech produced by inexperienced signers during simultaneous communication.

This study investigated sentence duration and voice onset time (VOT) of plosive consonants in words produced during simultaneous communication (SC) by inexperienced signers. Stimulus words embedded in a sentence were produced with speech only and produced with SC by 12 inexperienced sign language users during the first and last weeks of an introductory sign language course. Results indicated significant differences between the speech and SC conditions in sentence duration and VOT of initial plosives at both the beginning and the end of the class. Voiced/voiceless VOT contrasts were enhanced in SC but followed English voicing rules and varied appropriately with place of articulation. These results are consistent with previous findings regarding the influence of rate changes on the temporal fine structure of speech (Miller, 1987) and were similar to the voicing contrast results reported for clear speech by Picheny, Durlach, and Braida (1986) and for experienced signers using SC by Schiavetti, Whitehead, Metz, Whitehead, and Mignerey (1996).

Adult↗
PubMedDate not supplied

Effect of vowel environment on consonant duration: an extension of normative data to adult contextual speech.

In this study, we investigated the effect of vowel environment on consonant duration in contextual speech produced by adults. Previous studies, such as Schwartz's published in 1969 and DiSimoni's in 1974, of vowel influence on consonant duration have supported the notion of anticipatory scanning in which final vowel targets influence the duration of preceding fricative consonants. These studies were based on repetitions of nonsense syllables by children and adults, but no research has been reported that extends these data to contextual speech or examines speaker gender differences. Forty adult normal speakers (20 women and 20 men) recorded palatal and alveolar fricatives produced in four vowel environments in words embedded in contextual sentences. Results indicated significant effects of vowel context on consonant duration in contextual speech and revealed anticipatory scanning effects that are similar to those seen with nonsense syllables in previous studies. These normative data can form the basis for comparison of the effects of temporal alterations produced by speaking conditions such as simultaneous communication.

Adult↗
PubMed1991

The effects of a maxillary speech-aid prosthesis for the combined tongue and mandibular resection patient.

The purpose of this investigation was to develop a protocol for the fabrication of a prosthesis that would improve speech in individuals who have undergone complete removal of the tongue and mandible. A 60-year-old man was suffering from severe xerostomia and was unable to produce intelligible speech. Speech analysis without the prosthesis revealed a profound articulatory disorder. With the prosthesis, xerostomia was eliminated and the subject had fewer articulatory errors of severity. Improvement in speech intelligibility was significant at p less than 0.001.

Articulation Disorders↗
PubMedDate not supplied

Speaking behavior and speech sound characteristics in acute schizophrenia.

Based on a sample of 45 hospitalized, acute-schizophrenic patients and 45 carefully matched controls, we investigated the non-verbal characteristics of schizophrenic speech by means of an 'acoustic' speech analysis and determined the extent to which speaking behavior and speech sound characteristics had adjusted toward normal values at the time of hospital release. Using a multivariate discriminant function derived from a previous study of chronic schizophrenics, totally 77 (85.6%) individuals of our patient and control sample could be correctly classified by a set of 12 acoustic variables at entry into study. At hospital release, the majority of patients (64.4%) still exhibited speech impairment although acute psychopathology had significantly improved. A configuration of 6 acoustic variables, assessed at the time point of entry into study, predicted at high reliability the severity of the negative syndrome at hospital release. Acute medication effects did not explain these findings, thus underlining the potential diagnostic relevance of the speech analysis method. With respect to the relationship between speech characteristics and acute psychopathology throughout the time course of recovery, our results suggest that changes in speaking behavior and speech sound characteristics may be distinct aspects of schizophrenia that can persist in a subgroup of patients over a long period, mostly beyond the time point of hospital release. Accordingly, the speech analysis method might become very useful in detailing the nature and severity of deficits in patients after remission of positive symptoms.

Acute Disease↗
PubMed1991

Urophonographic studies of benign prostatic hypertrophy.

The sonic detection and recording systems of urethral sounds generated during micturition were developed. This procedure was tentatively postulated as "urophonography" and its recording diagram as a "urophonogram". Classification of urophonograms was done on the basis of analyzing normal healthy male volunteers and patients with benign prostatic hyperplasia. Four types of urophonograms were demonstrated according to the shape and characteristics. Types 1, 2, 3 and 4 were characterized by a diamond shape, irregular occurrences of sound spikes, the mixture of Types 1 and 2 and no remarkable sound spikes respectively. Types 1, 2, and 3 were found in BPH, while Type 4 was demonstrated in normal healthy male volunteers. After prostatectomy a high percentage of Type 4 was demonstrated. The frequency (Hz) of these sounds was around 650. Diamond shape sound showed higher value of power gain (dB) than irregular type sound. The wave length was around 0.50 (m). Comparison of urophonographic studies with conventional uroflowmetric investigation was undertaken. Urophonography was useful for investigations of dysfunctional voiding and lower urinary tract obstruction.

Aged↗
PubMed1999

Laterality in the perception of temporal cues of musical timbre.

Laterality in the perception of non-stationary aspects of musical timbre was investigated in 54 right-handed non-musicians. Timbre differences were produced by altering the amplitude envelope of a steady-state complex tone. Two single-choice tests with attention directed to one ear were used--a dichotic test and a monaural test with contralateral white noise. Dependent variables were reaction time and accuracy. Both tests showed a significant left ear advantage for reaction time. For the accuracy variable, a significant left ear advantage was found only in the monaural test. Results are briefly discussed in terms of their compatibility with the generally accepted notion that spectral and temporal integrations of sounds are primarily functions of the right and left hemisphere, respectively.

Adult↗
PubMed2000

Perceptual and laboratory assessment of dysphonia.

The voice laboratory is an essential tool in the voice clinic. It provides a functional diagnosis of disturbed voice production, demonstrating the deviant characteristics, limitations, and possibilities for change. As voice is multidimensional, several aspects need to be documented, quantified, and analyzed: perception, stroboscopy, aerodynamics, acoustics, self-evaluation by the patient, and in specific cases, physiologic signals, such as electroglottography, flow glottography, nasometry, and electromyography. Effectiveness and outcome studies rely on such data.

Electromyography↗
PubMed1999

High-frequency ultrasonic vocalizations index conditioned pharmacological reward in rats.

We have proposed that short (<0.5 s), high-frequency (approximately 50 kHz) ultrasonic vocalizations ("50-kHz USVs") index a positive affective state in adult rats, because they occur prior to rewarding social interactions (i.e., rough-and-tumble play, sex). To evaluate this hypothesis in the case of nonsocial stimuli, we examined whether rats would make increased 50-kHz USVs in places associated with the administration of rewarding pharmacological compounds [i.e., amphetamine (AMPH) and morphine (MORPH)]. In Experiment 1, rats made a greater percentage of 50-kHz USVs on the AMPH-paired side of a two-compartment chamber than on the vehicle-paired side, even after statistical correction for place preference. In Experiment 2, rats made a higher percentage of 50-kHz USVs on the MORPH-paired side than on the vehicle-paired side, despite nonsignificant place preference. These findings support the hypothesis that 50-kHz USVs mark a positive affective state in rats and introduce a novel and rapid marker of pharmacological reward.

Affect↗
PubMed2003

Temporal integration of speech prosody is shaped by language experience: an fMRI study.

Differences in hemispheric functions underlying speech perception may be related to the size of temporal integration windows over which prosodic features (e.g., pitch) span in the speech signal. Chinese tone and intonation, both signaled by variations in pitch contours, span over shorter (local) and longer (global) temporal domains, respectively. This cross-linguistic (Chinese and English) study uses functional magnetic resonance imaging to show that pitch contours associated with tones are processed in the left hemisphere by Chinese listeners only, whereas pitch contours associated with intonation are processed predominantly in the right hemisphere. These findings argue against the view that all aspects of speech prosody are lateralized to the right hemisphere, and promote the idea that varying-sized temporal integration windows reflect a neurobiological adaptation to meet the 'prosodic needs' of a particular language.

Adult↗
PubMed2003

The effect of spectral manipulations on the identification of affective and linguistic prosody.

We investigated the effect of various spectral manipulations on the identification of sentential prosody. Two main categories of prosody--affective (happy, angry, sad) and linguistic (statement, question, continuation)--were studied. Thirty-six subjects were presented with stimuli that were recorded by a female native speaker of American English. The stimuli were digitally manipulated to create synthesized, band-pass filtered (F0-range and F2/F3-range) and re-entrant (pitch only version of stimulus is convolved with a steady-state signal) conditions. Results of a forced-choice discrimination paradigm showed that, in general, performance is remarkably robust despite spectral manipulation, even when there is relatively little spectral information. However, performance was significantly degraded in the low band-pass and re-entrant conditions. These observations are discussed in light of the relevance of the fundamental frequency as well as syllabification for the analysis of prosodic information.

Adolescent↗