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Distance from an intrauterine hydrophone as a factor affecting intrauterine sound pressure levels produced by the vibroacoustic stimulation test.
OBJECTIVE: The purpose of this study was to determine whether intrauterine sound pressure levels produced by vibroacoustic stimulation were associated with distance from an intrauterine hydrophone in human parturients and to evaluate the effects of distance on the spectrum of the stimulus. STUDY DESIGN: Measurements of intrauterine sound were taken in eight volunteer parturients in normal active-phase labor by use of an intrauterine hydrophone. Vibroacoustic stimulation was performed on the maternal abdomen directly overlying the hydrophone; at distance of 5, 10, 15, 20, and 25 cm from the hydrophone; and at the maternal sternum. Intrauterine sound pressure levels were tape-recorded for later analysis. Fetal heart rate and fetal movement were assessed with each vibroacoustic stimulation. Spectral analyses were performed by taking the fast Fourier transform of the tape-recorded stimulation at each position. RESULTS: Analysis of variance with repeated measures indicated a statistically significant decrease (F = 4.1, p = 0.004) in the sound pressure levels as distance increased. Spectral analysis indicated large variability between and within subjects. CONCLUSION: Sound exposure of the fetal ear is on average decreased as the distance between the ear and the vibroacoustic stimulation is increased. The spectrum of the stimulus produced with vibroacoustic stimulation is highly variable.
An acoustic-speech study of patients who received orthognathic surgery.
Several reports have suggested that orthognathic surgery may influence speech patterns. The purpose of this study was to examine the formant frequency changes of speech following orthognathic surgery in patients whose speech was considered perceptually normal preoperatively and postoperatively. Speech samples were obtained from five patients (three patients with Class II, Division 1 malocclusions and two patients with Class III malocclusions). Significant second-formant frequency shifts were found for the vowel 'e' (as in 'seat'); however, only minor second-formant frequency variations were found for the vowels 'a' (as in 'sat') and 'u' (as in 'suit'). The pattern of formant frequencies before and after surgical treatment suggested that the speakers adjusted their articulation to accommodate the orthognathic surgery. Overall, the data from this study indicate that speech patterns may be reorganized after orthognathic surgery even though speech remains perceptually "normal."
False positives in recognition memory produced by cohort activation.
Cohort theory in spoken-word recognition assumes that a cohort of word candidates consistent with incoming sensory information is activated implicitly as a spoken sound stimulus unfolds over time. Five experiments examined implications of this internal-generation-of-words mechanism. In Experiments 1 and 2, a "base" word was disqualified (the sensory information was no longer consistent with the word) either early or late in the presentation of a spoken stimulus. On a later recognition-memory test, significantly more false-positive errors occurred to base words following presentations of study items that had late, compared to early, disqualification points. Experiments 3-5 tested whether this phenomenon could be accounted for in terms of overlapping features between non-word stimuli and their base words or in terms of a post-identification processing mechanism. Experiment 3 replicated Experiments 1 and 2, and demonstrated that differences in early and late disqualification points for non-word targets, unlike word targets, were not related to false-positive recognition memory errors. The study inter-item interval in Experiment 4 was reduced to 1 s to minimize the role of post-identification processing activities, and the results for both word and non-word targets were consistent with Experiment 3. A word-association task in Experiment 5 revealed that the late non-word derivations used in this research were on the average more effective stimuli than the early non-word derivations in eliciting their base words. However, even when comparisons were restricted to item sets with early and late non-words that were equally effective in eliciting base words, false-positive recognition memory errors to target words were higher following prior presentations of their late derived non-words than following prior presentations of their early derived non-words.
Expectancy in melody: tests of the implication-realization model.
The implication-realization model's description of tone-to-tone expectancies for continuations of melodies was examined. The model's predictions for expectancies are described with a small number of principles specified precisely in terms of interval size and direction of pitch. These principles were quantified and used to predict the data from three experiments in which listeners were required to judge how well individual test tones continued melodic fragments. The model successfully predicted listeners' judgments across different musical styles (British and Chinese folk songs and Webern Lieder), regardless of the extent of listeners' musical training (Experiments 1 and 2) or whether they were born and raised in China or the U.S.A. (Experiment 3). For each experiment, however, the collinearity of the model's predictors indicated that a simplified version of the model might predict the data equally well. Indeed, a revised and simplified model did not result in a loss of predictive power for any of the three experiments. Convergent evidence was provided in a reanalysis of data reported by Carlsen (1981) and Unyk and Carlsen (1987), whose listeners were required to sing continuations to two-tone stimuli. Thus, these findings indicate that the implication-realization model is over-specified. The consistency that was found across experimental tasks, musical styles, and listeners raises the possibility, however, that the revised version of the model may withstand the original model's claims of universality.
Analysis of perceptual confusions between nine sets of consonant-vowel sounds in normal and dyslexic adults.
It is widely accepted that most developmental dyslexics perform poorly on tasks which assess phonological awareness. One reason for this association might be that the early or "input" phonological representations of speech sounds are distorted or noisy in some way. We have attempted to test this hypothesis directly. In Experiment 1, we measured the confusions that adult dyslexics and controls made when they listened to nine randomly presented consonant-vowel (CV) segments [sequence: see text] under four conditions of increasing white noise masking. Subjects could replay stimuli and were under no obligation to respond quickly. Responses were selected with a computer mouse from a set of nine letter-strings, corresponding to the auditory stimuli, presented on a VDU. While the overall pattern of confusions made by dyslexics and controls was very similar for this stimulus set, dyslexics confused [sequence: see text] significantly more than did controls. In Experiment 2, subjects heard each stimulus once only and were forced to respond as quickly as possible. Under these timed conditions, the pattern of confusions made by dyslexics and controls was the same as before, but dyslexics took longer to respond than controls. The slower responses of dyslexics in Experiment 2 could have arisen because: (a) they were slower at processing the auditory stimuli than controls, (b) they had worse visual pattern memory for letter strings than controls, (c) they were slower than controls at using the computer mouse. In Experiments 3, 4 and 5 subjects carried out control tasks which eliminated each of these possibilities and confirmed that the results from the auditory tasks genuinely reflected subjects' speech perception. We propose that the fine structure of dyslexics' input phonological representations should be further explored with this confusion paradigm by using other speech sounds containing VCs, CCVs and VCCs.
Perception of acoustic correlates of major phrasal units by young infants.
How might young learners parse speech into linguistically relevant units? Sensitivity to prosodic markers of these segments is one possibility. Seven experiments examined infants' sensitivity to acoustic correlates of phrasal units in English. The results suggest that: (a) 9 month olds, but not 6 month olds, are attuned to cues that differentially mark speech that is artificially segmented at linguistically COINCIDENT as opposed to NONCOINCIDENT boundaries (Experiments 1 and 2); (b) the pattern holds across both subject phrases and predicate phrases and across samples of both Child- and Adult-directed speech (Experiments 3, 4, and 7); and (c) both 9 month olds and adults show the sensitivity even when most phonetic information is removed by low-pass filtering (Experiments 5 and (6). Acoustic analyses suggest that pitch changes and in some cases durational changes are potential cues that infants might be using to make their discriminations. These findings are discussed with respect to their implications for theories of language acquisition.
The application of fractal dimension to temporomandibular joint sounds.
Researchers have attempted to use mathematical analysis of the sounds produced by symptomatic temporomandibular joints (TMJ) as a diagnostic modality. However, previous studies have generally concluded that such analyses have little diagnostic utility. Previous studies using Fourier transforms and visual inspection were of limited success. This paper reports the results of a preliminary retrospective study using fractal analysis to analyze sounds produced by symptomatic temporomandibular joints previously diagnosed using other clinical modalities as having internal derangements with reducing discs. Multiple mandibular opening and closing cycles were recorded in four subjects. The study revealed that fractal analysis produced a high degree of reproducibility within, and similarity across subjects. The fractual dimension associated with joints having this pathology was found to be 1.266, revealing that fractal analysis shows promise as a noninvasive method for diagnosing interarticular TMJ pathology.
Song acquisition in photosensitive and photorefractory male European starlings.
We tested the ability of 1-year-old European starlings (Sturnus vulgaris) to acquire songs while in different physiological states. Photorefractory males, with low testosterone levels, learned songs as completely and as accurately as photosensitive males in full reproductive condition. This indicates that song acquisition in 1-year-old males does not depend on high levels of androgens. The ability to learn songs during the nonbreeding season may reflect the high song output of potential tutors through most of the year, including the photorefractory period, and may facilitate increases in song repertoire size in adulthood.
Antiphonal duetting and sex hormones in the tropical bush shrike Laniarius funebris (HARTLAUB).
We investigated changes in antiphonal duetting with phases of reproduction and circulating levels of luteinizing hormone, testosterone, and estradiol in slate-colored boubous (Laniarius funebris) breeding in aviaries. Frequency of overall male singing did not vary with reproductive phase while frequencies of female singing and female vocal responses to male song were reduced during incubation and feeding of nestlings. This resulted in significant changes in frequency of duetting. Males sang the sexual song type M1 more often during courtship and nest building than during the nestlings phase. Their territorial song types M2 and M4 did not vary with breeding phase. Females were less responsive to M1 during incubation and to M2 during the nest building and nestlings than during the courtship phase. Plasma levels of luteinizing hormone and testosterone increased in males from the prebreeding to the courtship phase. While testosterone decreased already during nest building and remained low during subsequent phases of reproduction, luteinizing hormone decreased during incubation and feeding of nestlings. Female luteinizing hormone levels were highest during nest building. Female estradiol levels decreased from nest building to incubation and increased again during subsequent nest building. Female testosterone levels were low but not basal and did not vary with phase. Neither the overall male and female singing frequencies nor the frequencies of male song types were correlated with hormonal state. However, female participation in territorial duets M4 correlated positively with their testosterone levels. It is suggested that in this monogamous, duetting species with prolonged pairbonds behavioral cues between the mates are more important than the hormonal state in control of male and female singing.
Androstenedione therapy reinstates normal, not supernormal, song structure in castrated adult male zebra finches.
In previous studies, androstenedione (AE) replacement therapy restored the highest levels and intensities of courtship song displays in castrated male zebra finches of any hormone tested. Furthermore, female zebra finches responded strongly to AE-treated males and preferred intact males given small AE implants to unsupplemented males. In this study, we asked whether AE treatment might alter song structure, since male song is an important cue in mate choice by female zebra finches. Songs of adult males were recorded. The males were then castrated and given AE therapy and recorded again. No differences were found between the courtship or undirected songs males sang before castration and after AE treatment. As in previous studies, the structure of a male's courtship song differed significantly from his undirected song, and the structural differences between these two song types were not altered by AE treatment.
Spectral analysis of muscular sound at low and high contraction level.
The activated muscle generates a low frequency rumbling noise, which is known as the Sound-MyoGram (SMG). Spectral analysis of the SMG is carried out in this work, in order to: (i) check the adequacy of both the Fast Fourier Transform (FFT) and the Maximum Entropy Spectrum Estimation (MESE). Because it is a well known technique, the FFT method is only briefly described, while the philosophy of the MESE method is given in more detail and completed with a description of the recursive algorithm; (ii) select a frequency parameter suitable to describe the SMG. For this purpose two well-defined physiological conditions (20% and 80% Maximal Voluntary Contraction) have been adopted in order to provide a safe reference for the interpretation of the findings. The results show that: (a) both FFT and MESE are adequate to estimate the SMG Power Spectrum; (b) both the mean and the median frequency are suitable parameters, the mean frequency being the more favourable one; (c) the SMG Power Spectrum is a promising tool to study the muscle activation modalities.
Instrumentation and validity for direct-readout voice onset time measurement.
Methods and instrumentation for direct readout of voice onset time (VOT) are presented along with sample measurements for three subjects. Mean VOT and intrasubject variability are compared with data obtained from wide-band spectrograms. The results suggest that the instrumentation described yields VOT values comparable to those obtained from wide-band spectrograms. Implications for diagnosis are discussed and research needs are identified.
Identification of normal and abnormally rough vowels by spectral noise level measurements.
Our goal in this study was to learn whether vowel spectral noise level (SNL) measurements might differentiate between normal and abnormally rough test vowel samples. The vowel samples studied were obtained originally for two previous investigations. In one study, 20 normal-speaking subjects phonated in isolation each of five test vowels both normally and with simulated abnormal vocal roughness. In the other, 20 subjects who individually presented a laryngeal pathology phonated each of the same test vowels in isolation. The 300 test samples available from the two studies were obtained at one intensity and mouth-to-microphone distance (75 dB SPL at 15 cm). From the original studies, narrow-band (3-Hz) acoustic spectra of the vowel samples and SNL measurements were available. For this study, a mean of 25 noise level measurements per vowel sample served as an SNL index for each test production. Additionally, for this study, the test samples were individually classified dichotomously as normal or as abnormally rough in quality by a panel of nine listeners. Data analysis resulted in the identification of an SNL mean value (termed the SNL "criterion") that appeared to differentiate effectively between the perceptually normal and abnormally rough samples of each test vowel. In general, the findings appeared to support the hypothesis that vowel SNL measurements could be used to identify normal and abnormally rough vowel samples.
Reliability of perceptual voice assessment.
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Acoustic measurement of voice quality in central dysphonia.
Speech samples of 14 male and 10 female patients with central dysphonia were examined. Eighteen patients had suffered a severe closed head trauma and the remaining six patients had experienced cerebrovascular accident (CVA). Several parameters were developed in order to find acoustic correlates for three major pathologic voice qualities in central dysphonia. The well know jitter parameter, fundamental period perturbation (PP), was adapted for our purposes and proved to be a good measure for rough voices, though the patients revealed less jitter than in peripheral dysphonia. The vocal onset parameter, time lag of preexhalation (Tb), and the spectral parameter, spectral energy above 5 KHz (A5), classified the breathy voices. Most of the tense voices could be detected by the spectral parameters, spectral energy in the 1-5 KHz range (A1), and variance of spectral energy above 5 KHz (V5). The successful classification of these voice qualities allowed the description of compound pathologic voice types in central dysphonia.
Directional perturbation factors for jitter and for shimmer.
Directional perturbation factors for jitter and shimmer were calculated from the sustained production of the vowels /i/, /a/, and /u/ by 20 adult male and 20 adult female speakers. Directional factors for jitter were less than directional factors for shimmer. Shimmer directional factors for females had greater values than for the male speakers. Speculations on the relationship of directional factors and magnitude factors are made with reference to the laryngeal reflexogenic system. The usefulness of directional factors to early diagnosis of laryngeal disease are discussed.
Disturbances of the temporal organization of speech following bilateral thalamic surgery in a patient with Parkinson's disease.
This report summarizes a detailed analysis of the speech of a 45-yr-old man who had become dysarthric following bilateral thalamic surgery for the relief of symptoms of Parkinson's disease. His speech was characterized by a rapid rate and a mild-to-moderate articulatory deficit. Intelligibility was markedly reduced. The rapid rate was found to be the result of decreased syllable durations rather than to changes in pause or phrase patterns. Decreased syllable durations resulted from abnormal shortening of vowels. Consonant releases were found to be prolonged. This distorted temporal relationship among speech segments was considered to be an important factor in the patient's poor intelligibility and partially explained why uniform electronic expansion of his speech resulted in only negligible increase in intelligibility. It is hypothesized that this speech disturbance results from the interaction of central "metronomic" abnormality with a peripheral neuromotor articulatory impairment.