Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Sound Spectrography”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 901 records · Page 50Linked to original sources
PubMed1982

Acoustic properties of pathologic reiterative utterances: a case study of palilalia.

Acoustic analyses of the reiterative utterances of one subject demonstrate a high degree of similarity among the members of a repetition train. The acoustic data did not confirm for this patient the published description of palilalia as a reiteration of utterances in a context of increasing rate and decreasing loudness. In fact, the final utterance in a repetition train often had either a longer duration, greater intensity, or more pronounced fundamental frequency change (or any combination of these) than its predecessors. It is suggested that these may be more than one type of pathological reiterative utterance.

Adult↗
PubMed1982

Spectrographic study of vowels in stutterers' fluent speech.

Measurements were made of the formant frequencies and formant transitions associated with the vowels /i/, /ae/ and /u/ produced by seven moderate-to-severe stutterers when they read fluently in a control (normal) condition and under four experimental condition: masking noise, delayed auditory feedback, rhythmic pacing, and whispering. The first and second formant frequencies in an isolated /hVd/ context were more centralized than those reported for nonstutterers. The formant frequencies were centralized even more in reading, but varied little across conditions despite changes in fluency, speaking rates, and vowel duration. Duration and rate of formant transitions also were essentially the same across conditions. These findings and those reported in other studies indicate that stutterers' vowel production is more restricted, spatially and temporally, than nonstutterers'.

Adolescent↗
PubMed1982

Acoustical characteristics of intended syllabic stress in excellent esophageal speakers.

The ability of excellent esophageal speakers to manipulate acoustical characteristics associated with intended syllabic stress was studied. Five excellent esophageal speakers and five sex- and age-matched normals produced 10 sentence pairs, each containing a bisyllabic stimulus item differing only in primary stress placement. The mean fundamental frequency, sound pressure level, and duration of the stressed and unstressed vowel nuclei were analyzed. Although some differences in absolute levels were apparent, only sound pressure level differences reached statistical significance. For both groups, intended primary stress was associated with a comparable pattern of increased fundamental frequency, sound pressure level, and duration. The present findings suggest that excellent esophageal speakers are capable of producing some correlates of primary syllabic stress in a fashion remarkably similar to but somewhat less consistent than normals. The implications of these data for long-range clinical planning are discussed.

Adult↗
PubMed1983

Voice onset time in young and 70-year-old women.

This study was conducted to determine the effect of aging on voice onset time (VOT). Ten women between 20 and 30 years old and 10 women between 70 and 80 years old read CVC syllables embedded in a carrier phrase. Spectrograms were used to measure VOT for voiced and voiceless bilabial and velar stops in the context of high and low vowels. Findings revealed that VOT was generally the same in older and younger subjects, and both age groups maintained similar voiced/voiceless and bilabial/velar distinctions. Older subjects demonstrated significantly shorter VOTs only in certain contexts involving place of consonant production and vowel context. The effects of aging on VOT, therefore, seem to appear only in selected phonetic contexts.

Adult↗
PubMed1983

The accuracy of formant frequency measurements: a comparison of spectrographic analysis and linear prediction.

The accuracy of spectrographic techniques and of linear prediction analysis in measuring formant frequencies is compared. The first three formant frequencies of 90 synthetic speech tokens were measured by three experienced spectrographic readers and by linear prediction analysis. For fundamental frequencies between 100 and 300 Hz, both methods are accurate to within approximately +/- 60 Hz for both first and second formants. The third formant can be measured with the same degree of accuracy by linear prediction, but only to within +/- 110 Hz by spectrographic means. The accuracy of both methods decreases greatly when fundamental frequency is 350 Hz or greater. These limits of measurement appear to be within the range of the difference limens for formant frequencies.

Communication Devices for People with Disabilities↗
PubMed1983

Spectrographic analysis of vowel and word duration in apraxia of speech.

Most normal speakers of English reduce the duration of the stem word vowel as words increase in length. Theoretically, this durational reduction reflects low-level linguistic knowledge. We posed two questions in this study: First, do speakers with apraxia of speech progressively reduce vowel durations as words increase in length, and second, do these vowel and word durations differ significantly from normal productions? We asked 11 apraxia of speech patients and 11 normal speakers to repeat three sets of three words which progressively increased in length, and we analyzed these productions spectrographically. Our results revealed that both groups reduced vowel duration as words increased in length. Word and vowel duration for apraxia of speech patients, however, were often significantly longer than those for normal speakers. Our results suggest that vowel reduction is a robust phenomenon which resists impairment in apraxia of speech, despite often significant disturbances in motor programming.

Adult↗
PubMed1983

Acoustic patterns of apraxia of speech.

Apraxia of speech (or verbal apraxia) is a controversial disorder, considered by some to be an impairment of the motor programming of speech. Because the disorder is characterized by "higher order" errors such as metathesis and segment addition as well as by errors of apparent dyscoordination of articulation, it seems to reflect a relatively high level of damage to the nervous system. This report presents acoustic descriptions of the speech of seven persons diagnosed as having apraxia of speech but without severe aphasic impairment, especially agrammatism. The acoustic results indicate a variety of segmental and prosodic abnormalities, including slow speaking rate with prolongations of transitions, steady states, and intersyllable pauses; reduced intensity variation across syllables; slow and inaccurate movements of the articulators; incoordination of voicing with other articulations; initiation difficulties; and errors of selection or sequencing of segments. These error patterns are discussed with respect to a theory of motor control based on spatial-temporal schemata. In addition, consideration is given to the controversy about phonologic versus motor programming impairment in apraxia of speech.

Adult↗
PubMed1983

Formant frequency fluctuation as an index of motor steadiness in the vocal tract.

Involuntary movement of the articulatory structures can interfere with the accurate placement of the articulators during consonant production and may also result in distortion of vowel quality. An acoustic method was used to assess motor steadiness in the vocal tract musculature superior to the glottis during vowel production by five subjects with abnormal involuntary orofacial movements associated with tardive dyskinesia and 10 normal subjects. A linear predictive coding technique of spectral analysis yielded formant frequencies from the sustained productions of /a/. Based on the premise that changes in vocal tract configuration can be measured as changes in formant frequency, the sequential segment-to-segment fluctuations of the second formant frequency of these vowel samples were computed and used as an index of motor steadiness. Results showed that formant frequency fluctuation measures for four of the five tardive dyskinetic patients were substantially larger than those of the normal subjects, indicating a reduction of motor steadiness in these four subjects. Factors influencing the validity of this procedure and implications for its use are discussed.

Adult↗
PubMed1983

A noninvasive acoustic method using frequency perturbations and computer-generated vocal-tract shapes.

This study investigated improved processing of acoustic data with two adult Down's syndrome subjects. Sustained vowel samples were processed through a fast-Fourier-transform spectrum analyzer, and digital waveform data were used to obtain period-by-period measurements of the fundamental frequencies. Unusual frequency perturbation (jitter), later identified as diplophonia, was found for one of the Down's subjects. In addition, the first three formant frequencies of the vowels were determined and, utilizing an algorithm described by Ladefoged and his colleagues, computer-generated vocal-tract shapes were plotted. Differences in vocal-tract shapes, especially for the back vowels, were observed between the Down's female and the normal shape. Correlations between vocal-tract shapes of the Down's subjects and those for a normal man or woman were computed. A partial three-way factor analysis was carried out to determine those load factors or coefficients for each subject that were due to individual differences. These procedures, offering synthesized techniques portraying the interpharyngeal/oral functioning of the speech structures, may eventually have direct noninvasive diagnostic and therapeutic benefit for voice/resonance-disordered clients.

Adult↗
PubMed1983

Chest wall vibrations in singers.

The chest wall vibrations generated by phonation were examined with respect to origin, amplitude, and spectrum in seven singers. The vibrations were picked up in male and female singer subjects by means of small accelerometers, which were fastened to the skin on the center of the sternum, and, for the purpose of comparison, on the thyroid cartilage and on the trachea a few cm below the larynx. Among the factors which influence the chest wall vibrations, the subglottal pressure oscillations seem to represent the most important excitation, while the mechanical shocks from the vocal fold vibrations seem secondary. Supra- and subglottal resonances seem moderately influential. The results of the investigation suggest that it is the voice source, particularly the amplitude of its fundamental, which is reflected in the chest wall vibrations. The amplitude of these vibrations seem to lie above the threshold of the Pacinian receptors for vibratory sensation as long as the fundamental frequency is below approximately 300 Hz. The amplitude of the voice source fundamental and hence the sensation of chest vibrations vary considerably as phonation is changed along the phonatory dimension which ranges from "pressed/tense/strained" through "flow" to "breathy" phonation. For this reason it seems likely that the sensation of chest vibrations can serve as a useful nonauditory and hence room-independent signal for the voluntary control of phonation.

Adult↗
PubMed1983

Automatic analysis of voice fundamental frequency and intensity using a visi-pitch.

This research note describes a method for automatic analysis of voice fundamental frequency and intensity using a Visi-Pitch Model 6087 and an Apple II computer equipped with an analog-to-digital converter (TecMar AD-211). The method provides a simple means of quantizing fundamental frequency and intensity and extracting their distributional characteristics from the Visi-Pitch, an instrument which is gaining wide-spread use by speech pathologists, audiologists, and linguists for clinical and research purposes.

Computers↗
PubMed1983

An accelerometric measure as a physical correlate of perceived hypernasality in speech.

This study investigated the correlation between a physical measure of oral-nasal coupling and perceived hypernasality in speech. A modified accelerometric method was utilized to extract distributional characteristics of a ratio of the nasal accelerometric amplitude to the voice amplitude during simulated hypernasal reading by 11 female talkers. Perceived hypernasality scores for the readings were derived from a panel of 30 listeners in a paired-comparison paradigm. A correlation coefficient of .92 was obtained between the mean nasal-to-voice ratio and the perceived hypernasality scores. The results indicated that the nasal-to-voice amplitude ratio is a promising index of perceived hypernasality in speech.

Adult↗
PubMed1983

Voicing contrasts and their phonological implications in the speech of articulation-disordered children.

Five-year-old articulation-disordered children, some classified as substituters and some as syllable reducers, were compared with normal child and adult controls in their production of voicing contrasts. These contrasts occurred in minimal pairs containing word-final obstruents and in minimal triples containing word-initial stops and /s/-plus-stop clusters in initial position. Measures of vowel duration, voice onset time (VOT), and frequency of use of phonetic voicing were made from spectrograms. In every comparison the substituters' performance resembled that of the normal controls, as did the syllable reducers' use of VOT in stop singles. The syllable reducers used larger vowel duration ratios than the normal controls in a few minimal pairs and used phonetic voicing less often in word-initial /b d g/. The production data and previously reported perception data were examined for evidence that individual syllable reducers had voicing contrasts in underlying phonological form despite their deletions of obstruents in which these contrasts occurred. Most of the syllable reducers appeared to recognize underlying voicing contrasts in at least a few final obstruents and in some of the initial stop singles.

Articulation Disorders↗
PubMed1983

Deaf speakers' laryngeal behavior.

The purpose of this study was to compare deaf speakers' (n = 4) laryngeal behavior during voiced and voiceless consonant productions to that of normal hearing subjects (n = 4). Laryngeal behavior during these two speaker groups' productions of six word-initial stop plosives (/b d g p t k/) and fricatives (/v z delta f s pheta/) was visually observed by means of a flexible fiberoptic nasolaryngoscope (fiberscope). The visualizations and their acoustic correlates were audiovisually recorded. The audiovisual recordings were analyzed by means of both frame-by-frame categorical judgments of laryngeal behavior and broad phonetic transcriptions of the accuracy/inaccuracy of consonantal voicing. Results indicated that deaf speakers' laryngeal behavior during production of those consonants perceived as accurately voiced was comparable to that of normal speakers, whereas deaf speakers' laryngeal behavior during production of consonants perceived as inaccurately voiced generally differed in various ways from normal. Findings seem to suggest that some aspects of deaf speakers' atypical laryngeal behavior associated with inaccurately voiced consonants may be due to an aberrant linguistic system while other aspects may be due to inadequate laryngeal motor control.

Adult↗
PubMed1984

Harmonics-to-noise ratio and psychophysical measurement of the degree of hoarseness.

The degree of hoarseness can be evaluated by judging the extent to which noise replaces the harmonic structure in the spectrogram . The relationship between these two components was quantified as the harmonics-to-noise (H/N) ratio. Eighty-seven phonatory samples (sustained vowel /a/), ranging from nearly normal to severely hoarse, were analyzed. The H/N ratio, the spectrographic classification, and cycle-to-cycle pitch perturbations (jitter) each showed a significant correlation with the psychophysical measurement of the degree of hoarseness (r = .809, .805, and .712, respectively; p less than .001). The analysis also revealed that the correlations of the psychophysical measurement of the degree of hoarseness with the first two parameters were significantly higher than that with jitter (p less than .05). Moreover, the spectrographic classification is subjective, and its scale is discrete and coarse. Therefore, the H/N ratio seems to be the most applicable in the clinic as a quantitative index of the degree of hoarseness.

Hoarseness↗
PubMed1984

Analysis of stutterers' voice onset times and fundamental frequency contours during fluency.

The purpose of this study was to examine stutterers' and nonstutterers' fluent voice onset time (VOT) and fundamental frequency (Fo) contour measures from target syllables located at the beginning of a carrier phrase. Ten adult male stutterers were matched within one year of age with 10 adult male nonstutterers. Oscillographic and spectrographic analyses of subjects' VOT and Fo at vowel onset, average vowel Fo, and speed and range of Fo change were obtained from fluent productions of 18 stop consonant-vowel syllables. Results showed that VOTs for voiced stops and the range of Fo change for voiceless stops were associated with significant between-group differences. All other dependent measures were not significantly different between the two groups. When compared with past research, these findings indicate that greater differences emerge between stutterers and nonstutterers when measures of fluency are taken at the beginning than in the middle of a carrier phrase. Implications for future research are discussed.

Adolescent↗
PubMed1984

Microprocessor-based speech processing system.

Durational measurements of frication, aspiration, prevoicing, and voice onset are often difficult to perform from the spectrogram, and the resolution is limited to about 5 ms. In many instances, a higher resolution can be obtained from a study of waveforms than from a study of spectrum. We present a microprocessor-based speech acquisition and processing system which uses waveform analysis techniques to extract measurements from the acoustic signal. The system is low cost and portable; it operates in "real time" and employs noninvasive data-capturing techniques. The usefulness of the system is demonstrated in the VOT measurement of CV clusters and in the measurement of fundamental frequency.

Computers↗