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Biomedical subjects

R D Kent

Publications and source records attributed to R D Kent.

At least 55 records · Page 3Linked to original sources
PubMed1979

Developmental study of vowel formant frequencies in an imitation task.

Imitations of ten synthesized vowels were recorded from 33 speakers including men, women, and children. The first three formant frequencies of the imitations were estimated from spectrograms and considered with respect to developmental patterns in vowel formant structure, uniform scale factors for vowel normalization, and formant variability. Strong linear effects were observed in the group data for imitations of most of the English vowels studied, and straight lines passing through the origin provided a satisfactory fit to linear F1--F2 plots of the English vowel data. Logarithmic transformations of the formant frequencies helped substantially to equalize the dispersion of the group data for different vowels, but formant scale factors were observed to vary somewhat with both formant number and vowel identity. Variability of formant frequency was least for F1 (s.d. of 60 Hz or less for English vowels of adult males) and about equal for F2 and F3 (s.d. of 100 Hz or less for English vowels of adult males).

Adult↗
PubMed1977

Prevention of Salmonella typhimurium infection inpoultry by pretreatment of chickens and poults with intestinal extracts.

Day-old chickens or turkey poults when pretreated with an oral dose of intestinal fluid froma healthy adult bird, were considerably more resistant to the subsequent establishment of Salmonella typhimurium in their intestinal tract than were non-treated chickens or turkey poults. Caecal fluid was more effective as a pretreatment than were washings taken from other parts of the gastro-intestinal tract of a healthy adult bird. This increased resistance of pretreated chickens or poults is thought to result from the rapid establishment of a conventional indigenous microflora which inhabits establishment and growth by the invading enteric pathogen.

Animals↗
PubMed1976

Paroxysmal ataxic dysarthria.

This report reviews 13 cases in which a dysarthria appeared, remitted, and reappeared within seconds. The speech pattern of each case was characteristic of ataxic dysarthria. A cinefluorographic film for one of the subjects provided a rare opportunity to study the articulatory dynamics of this disorder. Multiple sclerosis either was given as a diagnosis or was strongly suspected in each case, and carbamazepine has been an effective treatment. Speculations concerning the origin of the paroxysmal and ataxic character of the dysarthria are presented along with a preliminary checklist for identifying the disorder.

Acoustics↗
PubMed1976

Anatomical and neuromuscular maturation of the speech mechanism: evidence from acoustic studies.

This paper surveys acoustic studies of speech development and discusses the data with respect to the anatomical and neuromuscular maturation of the speech mechanism. The acoustic data on various aspects of speech production indicate that the accuracy of motor control improves with age until adult-like performance is achieved at about 11 or 12 years, somewhat after the age at which speech sound acquisition usually is judged to be complete. Other topics of discussion are (1) problems in the spectrographic analysis of children's speech, (2) formant scale factors that relate children's and adults' data, and (3) identification and diagnosis of developmental disorders through acoustic analyses of speech sounds.

Acoustics↗
PubMed1975

Cineradiographic assessment of articulatory mobility in the dysarthrias.

This paper describes cineradiographic techniques for the assessment of articulatory mobility in dysarthric subjects. Sample data for the mobility ranges of articulatory points on the tongue, lower lip, and jaw are presented for four normal speakers and four dysarthric speakers. In addition, fleshpoint displacements during the articulatory movements of the dysarthric subjects are used to illustrate abnormalities in the range, rate, and direction of speech movements. Discussion of the point-parameterized cineradiographic data emphasizes possibilities for the clinical evaluation of dysarthric impairments.

Cineradiography↗
PubMedDate not supplied

Research on speech motor control and its disorders: a review and prospective.

This paper reviews issues in speech motor control and a class of communication disorders known as motor speech disorders. Speech motor control refers to the systems and strategies that regulate the production of speech, including the planning and preparation of movements (sometimes called motor programming) and the execution of movement plans to result in muscle contractions and structural displacements. Traditionally, speech motor control is distinguished from phonologic operations, but in some recent phonologic theories, there is a deliberate blurring of the boundaries between phonologic representation and motor functions. Moreover, there is continuing discussion in the literature as to whether a given motor speech disorder (especially apraxia of speech and stuttering) should be understood at the phonologic level, the motoric level, or both of these. The motor speech disorders considered here include: the dysarthrias, apraxia of speech, developmental apraxia of speech, developmental stuttering, acquired (neurogenic and psychogenic) stuttering, and cluttering.

Adolescent↗
PubMedDate not supplied

Voice dysfunction in dysarthria: application of the Multi-Dimensional Voice Program.

Phonatory dysfunction is a frequent component of dysarthria and often is a primary feature noted in clinical assessment. But the vocal impairment can be difficult to assess because (a). the analysis of voice disorder of any kind can be challenging, and (b). the voice disorder in dysarthria often occurs along with other impairments affecting articulation, resonance, and respiration. A promising assessment tool is multi-parameter acoustic analysis, such as the Multi-Dimensional Voice Program (MDVP). Part 1 of this paper recommends procedures and standards for the acoustic analysis of voice, including (1). selection of the sample to be analyzed, (2). signal quality requirements, (3). availability of normative data for both genders and different ages of speakers, (4). reliability of analysis, and (5). correlation of acoustic results with results from other methods of analysis. In Part 2, acoustic data are reviewed for the dysarthria associated with Parkinson disease (PD), cerebellar disease, amyotrophic lateral sclerosis (ALS), traumatic brain injury (TBI), unilateral hemispheric stroke, and essential tremor. Tentative profiles of voice disorder are described for these conditions. These profiles may serve as hypotheses for future research. Although several issues remain to be resolved in the acoustic analysis of voice disorder in dysarthria, steps can be taken now to promote the reliability, validity, and clinical utility of such analyses. (1). As a result of this activity, the participant will be able to describe ways in which an optimal multi-dimensional analysis of voice can be performed with modern acoustic analysis systems. (2). As a result of this activity, the participant will be able to apply multi-dimensional acoustic analysis of voice to individuals who have a dysarthria-related voice disorder. (3). As a result of this activity, the participant will be able to identify major sources of normative data on the Multi-Dimensional Voice Program.

Amyotrophic Lateral Sclerosis↗
PubMedDate not supplied

Acoustic studies of dysarthric speech: methods, progress, and potential.

EDUCATIONAL OBJECTIVES: (1) The reader will be able to describe the major types of acoustic analysis available for the study of speech, (2) specify the components needed for a modern speech analysis laboratory, including equipment for recording and analysis, and (3) list possible measurements for various aspects of phonation, articulation and resonance, as they might be manifest in neurologically disordered speech.

Dysarthria↗
PubMedDate not supplied

Neuroimaging studies of brain activation for language, with an emphasis on functional magnetic resonance imaging: a review.

Neuroimaging studies have greatly enhanced the potential to understand brain-behavior relationships in complex behaviors such as language. The method of functional magnetic resonance imaging (fMRI) is one of the newest tools for neuroimaging, and it will in all likelihood contribute substantially to new knowledge about brain activation for language processing. This review summarizes basic information about fMRI, including principles of operation, experimental pitfalls and examples of application to language.

Brain↗
PubMedDate not supplied

Task-based profiles of the dysarthrias.

The dysarthrias are associated with a variety of motor disturbances distributed over several motor systems of speech production. The features of a given dysarthria often vary with the speaking task, and this task-dependency affords insights into the responsible neural lesion and its effects on the motor regulation of speech. Each task also is amenable to quantitative analyses with acoustic or physiologic methods, and these analyses may redefine the value of these speaking tasks. This article considers task-based analyses for the dysarthrias associated with Parkinson's disease, cerebellar disease, and stroke.

Brain Infarction↗