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Biomedical subjects

J W Folkins

Publications and source records attributed to J W Folkins.

At least 19 recordsLinked to original sources
PubMed1996

Speech timing in apraxia of speech versus conduction aphasia.

This study examined temporal parameters of speech in subjects with apraxia of speech, conduction aphasia, and normal speech. They were asked to repeat target words in a carrier phrase 10 times. Acoustic analyses involved measurement of stop gap duration, voice onset time, vowel nucleus duration, and consonant-vowel (CV) duration. Speakers with apraxia of speech had longer and more variable stop gap, vowel, and CV durations than did subjects with aphasia or normal speech. Speakers with conduction aphasia had longer vowel durations and CV durations than subjects with normal speech. Also, subjects with apraxia of speech showed greater token-to-token variability than the other subject groups. The variability shown by subjects with apraxia of speech was significantly correlated with perceptual judgments of their speech. The significance of these results is discussed in the context of motoric and phonological explanations for apraxia of speech and conduction aphasia.

Adult↗
PubMed1994

Coordination of velopharyngeal muscle activity during positioning of the soft palate.

The relative contributions of the levator veli palatini, palatoglossus, and palatopharyngeus muscles were assessed relative to a range of positions of the velopharynx during production of the vowels [a] and [i] by four normal adult speakers. The results indicate that velopharyngeal positioning is determined by the relative contributions of the levator veli palatini, palatoglossus, and palatopharyngeus muscles. There was an increase in coefficients of determination (i.e., amount of closure level variability explained) when activity levels of all three muscles are included in the statistical model compared to activity in any one muscle analyzed independently. Both consistent and inconsistent relations among activity levels in the three velopharyngeal muscles studied were observed across speaker and vowel produced.

Adult↗
PubMed1993

Visuomotor tracking ability of young adult speakers.

This study was conducted to (a) study the ability of young adult subjects to track target signals with the lower lip, jaw, or larynx, (b) examine subjects' abilities to track different sinusoidal frequencies and unpredictable target signals, and (c) test notions of response mode and predictive mode tracking reported for nonspeech structures by previous authors (e.g., Noble, Fitts, & Warren, 1955; Flowers, 1978). Twenty-five normal speakers tracked sinusoidal and unpredictable target signals using lower lip and jaw movement and fundamental frequency modulation. Tracking accuracy varied as a function of target frequency and articulator used to track. The results quantify the visuomotor tracking abilities of normal speakers using speech musculature and show the potential of visuomotor tracking tasks in the assessment of speech articulatory control.

Adult↗
PubMed1993

Air pressure regulation during speech production.

Vocal tract pressures during speech tend to be maintained in the face of airway leaks that might be encountered by individuals with repaired palatal clefts. This study tested the hypothesis that such constant pressures can be explained as a consequence of constant pressure source characteristics of the respiratory system during speech production. This conceptualization differs from pressure regulation theories [e.g., D. Warren, Cleft Palate J. 23, 251-260 (1986)] which posit that active reflexive compensatory responses occur to regulate air pressure during speech. Four experiments were conducted to (a) confirm the distinction between constant flow versus constant pressure sources using a plastic vocal tract model, (b) compare air pressure and flow patterns associated with airway leaks in normal speakers to model data, (c) study the effects of gas density in the vocal tract model on air pressure and air flow patterns predicted by a nonreflexive constant pressure source hypothesis, and (d) compare air pressure and air flow patterns associated with airway leaks obtained from normal speakers using different gas densities to model data. Overall, observed flow and pressure patterns suggest the possible influence of constant pressure source characteristics of the respiratory system during speech on maintenance of intraoral air pressure.

Adult↗
PubMed1993

Levator veli palatini muscle activity in relation to intranasal air pressure variation.

Continuous positive airway pressure (CPAP) therapy can be used to reduce hypernasality by elevating the air pressure in the nasal cavities during speech. The purpose of this study was to determine whether increased intranasal air pressure loads the major muscle of velopharyngeal closure, the levator veli palatini. Nine subjects, four with cleft palate and five without cleft palate, were studied. Electromyographic activity was measured from the levator veli palatini muscle with several levels of air pressure delivered to the nasal cavities using a commercially available CPAP instrument. It was found that levator veli palatini activity was significantly greater for the positive air pressure conditions than for the atmospheric pressure conditions for both subject groups. This indicates that the levator veli palatini muscle acts against the resistive load produced by the increased intranasal air pressure. The results support the use of CPAP therapy as a method of resistance exercise for strengthening velopharyngeal closure muscles.

Adult↗
PubMed1991

Scaling and transcription measures of intelligibility for populations with disordered speech.

Although Samar and Metz (1988) have addressed significant issues regarding the assessment of the intelligibility of hearing-impaired talkers, we cannot agree with their interpretation of their findings. Because the transcription and rating-scale measures were performed on different types of speech samples, the two sets of scores cannot be compared. Moreover, transcription and scaling measures may provide fundamentally different estimates of speech performance. Investigators should select which measure to use after considering the appropriate construct validity and the purpose of the measurement.

Hearing Disorders↗
PubMed1991

The effects of auditory feedback on the regulation of intraoral air pressure during speech.

Previous experimental evidence has been interpreted as support for regulation of both acoustics and aerodynamics during speech production. One recent perspective is that although speech acoustics may be manipulated, regulation of aerodynamics is a central component of the processes that produce speech. From this perspective, it has been suggested that aerodynamic regulation is given priority over perceptual accuracy. The experiment attempted to test this hypothesis by forcing speakers into a choice between aerodynamic and acoustic regulation. The intensity level of frication (embedded in a carrier phrase) was selectively amplified or attenuated and fed back to the speaker on line. Intraoral air pressure was recorded in order to assess whether or not perturbed auditory feedback would result in aerodynamic compensation. Although compensatory changes in peak intraoral air pressure, pressure duration, and pressure curve area were seen in response to 30-dB alterations of frication, no systematic effects were seen for smaller auditory manipulations. Further, the compensations were less than what one might expect from a system controlling auditory output. Explanations of these findings and their implications for the control of speech production are offered.

Adult↗
PubMed1990

Taxonomies in biology, phonetics, phonology, and speech motor control.

This article begins with a review explaining the different purposes of biological taxonomies. Taxonomic units are often dependent on the purpose for which the taxonomy has been constructed. Biological taxonomies provide an analogy that we use to emphasize some of the distinctions among the units of phonetic transcription systems, competence phonologies, and performance phonologies. The units of both phonology and phonetic transcription are considered as possible units of the speech motor system, and some of the difficulties of this assumption are explained. Although phonemic units, like units of phonetic transcription, are useful for many purposes, it is not theoretically necessary to use units derived as part of competence phonologies in systems attempting to explain phonological performance or speech motor performance. In this regard, we challenge the concept of coarticulation, because it is based on assumptions about the role of phonological or phonetic units in speech motor control. We offer an integrated perspective that has implications for research in speech motor control and deficits of the speech motor system. We see speech motor deficits as distinct from, yet possibly interacting with, phonological deficits.

Humans↗
PubMed1990

Speech production time and judgments of disordered nasalization in speakers with cleft palate.

The purpose of this study was to investigate the effect of production time on the perception of disordered nasalization in children with cleft palate. The subjects with cleft palate included 5 who produced acceptable speech consistently, 5 who produced disordered nasalization consistently, and 10 who were inconsistent in the production of disordered nasalization. We examined a range of production times similar to those for the production of single-word and connected speech tasks. Ten judges used direct magnitude estimation to rate severity of disordered nasalization. An accelerometric ratio technique was used to estimate the extent and timing of nasal acoustic activity. The results showed that reducing the production time did not change perceptible nasalization.

Adolescent↗
PubMed1990

Jaw and lip movements of deaf talkers producing utterances with known stress patterns.

This investigation determined whether prelingually deaf talkers could correctly produce stressed and unstressed syllables across known changes in stress patterning and phonetic composition. Three deaf and three hearing adults spoke sets of homogeneous syllable strings with stress patterns that they could tap successfully with a finger. Strain gauge transduction of lower lip and jaw movement indicated that both deaf and hearing subjects produced different displacements and durations for the stressed and unstressed syllables, regardless of the stress pattern. Jaw movement did not become more variable with changes in phonetic composition of the syllables. The results show no evidence that motoric abilities (as assessed in lip and jaw movements) limit deaf talkers in producing desired stress patterns.

Adult↗
PubMed1989

Lip movement in apraxia of speech.

Peak articulatory velocity of the lower lip and temporal coordination between the upper and lower lips were studied in 5 neurologically impaired subjects with speech behaviors consistent with a diagnosis of apraxia of speech. Differences in velocity and the timing between the movement onset of the two lips were compared for accurate and inaccurate productions of words. Peak articulatory velocity also was measured during the productions of the syllable [pae] and during a nonverbal movement. There were no systematic differences across accurate and inaccurate productions of words in peak articulatory velocity or movement onsets of the two lips. Furthermore, there were no systematic changes in movement velocity related to speech rate. We conclude that some apraxic speakers do not have a defect in the ability to produce high movement velocities.

Adult↗
PubMed1989

The effects of emphasis on passage comprehension.

It may be inferred from reaction time studies that the location of emphasis on nouns and noun phrases facilitates their comprehension (understanding and memory). However, we know of no previous demonstration of improved passage comprehension in normal listeners associated with emphasis placement. The present experiment examined effects of emphasis on comprehension of 12 passages that were read aloud and tape recorded. Emphasis placement was varied by splicing sentences containing emphasized or nonemphasized noun phrases into passages without altering the wording of the passages. These passages, contrasting in emphasis, were presented to 60 listeners. Comprehension was measured with multiple-choice, recognition questions that required subjects to link ideas across sentences. Comprehension was accurate significantly more often when correct response alternatives had been emphasized (71%), than when incorrect alternatives had been emphasized (56%), or no emphasis occurred in passages (57%). Findings reflect enhanced comprehension of emphasized items in terms of their meaning links to other concepts presented in passages. Results support the pragmatic assumption that the role of emphasis is to delineate constituents important in discourse meaning.

Communication↗
PubMed1988

Interactions in the labial musculature during speech.

Interactions in electromyographic activity of the upper and lower lips during speech were studied by manipulating the magnitude of bursts of activity related to bilabial closure. Four pairs of electrodes were placed in the labial musculature in each of four normal-speaking young adults. Manipulation of muscle activity usually resulted in positively correlated changes in activity recorded from the other three electrode pairs. Similar effects were found when lower lip muscle activity was manipulated and when upper lip muscle activity was manipulated, suggesting there is no asymmetry in the interactions between lips. Measurements of lower lip closing movement often correlated with the modulated muscle activity, suggesting that the size of lip opening was varied to accommodate different closing forces. The flexibility of a system producing positive correlations in the activity of different labial regions is discussed and contrasted with the suggestions that there are complementary variations, producing negative correlations, in the activity of different labial muscles during speech.

Adult↗
PubMed1988

Velopharyngeal nomenclature: incompetence, inadequacy, insufficiency, and dysfunction.

Different usages of the terms velopharyngeal incompetence, velopharyngeal inadequacy, velopharyngeal insufficiency, and velopharyngeal dysfunction that are commonly found in the literature are reviewed. It is advocated that one should not attempt to use any of the terms to distinguish between neuromotor or structural causes for behavioral dysfunction. Although the terms can be used as synonyms, this is not always the case. When terms are used differently, it is important to make the specific usage clear from context.

Humans↗
PubMed1988

An electromyographic study of the musculus uvulae.

The musculus uvulae and the levator veli palatini muscle were studied with electromyography (EMG) in three normal young adult subjects. Patterns of EMG activity for the musculus uvulae were similar to those of the levator veli palatini for all three subjects. When differences in EMG activity between the two muscles were found, the tasks did not involve speech. The presence of the musculus uvulae along the nasal aspect of the velum may be important in filling the space between the elevated velum and the posterior pharyngeal wall. In addition, the musculus uvulae may function to modify stiffness of the tissue adjacent to the insertion of the levator veli palatini and to produce extension of the velum.

Adult↗
PubMed1987

Comparison of cineradiographic and photodetection techniques for assessing velopharyngeal function during speech.

This study investigated the extent to which high-speed lateral-view cineradiography and a photodetector system described by Dalston (1982) provided comparable information concerning velopharyngeal activity. We observed the production of isolated utterances and running speech for 2 subjects in three contexts. A comparison was made between the times at which the velopharyngeal port was observed by each method to begin opening, reach maximal opening, begin closing, and initially attain closure. The photodetector system was found to be sensitive to changes in velar position observed by cineradiography. The correlation between the magnitude of photodetector output and the magnitude of velar displacement from the posterior pharyngeal wall was .89 for Subject 1 and .78 for Subject 2. The lack of a perfect relation between the output of the photodetector device and movements of the velum observed by cineradiography was not unexpected given the two-dimensional limitation of lateral cineradiography and the complexity of events associated with changing port size. The significance of these findings is discussed with respect to the potential research and clinical uses of this photodetector system.

Cineradiography↗
PubMed1987

Upper lip, lower lip, and jaw interactions during speech: comments on evidence from repetition-to-repetition variability.

Six studies purporting to demonstrate complementary covariation in lip and jaw activity during speech are reviewed. The statistical procedures used to assess interactions among the upper lip, lower lip, and jaw movements are discussed for four different experiments analyzing repetition-to-repetition movement variation. The findings from two studies analyzing repetition-to-repetition variation for interactions in electromyographic activity recorded from either the jaw musculature or the labial musculature also are evaluated. It is concluded that these studies do not provide convincing evidence of complementary covariation among the articulators or the muscles.

Jaw↗