Biomedical subjects

K M Yorkston

Publications and source records attributed to K M Yorkston.

14 recordsLinked to original sources

PubMed1990

Extended communication samples of augmented communicators. I: A comparison of individualized versus standard single-word vocabularies.

Vocabulary selection for linguistically intact augmented communicators is a growing clinical concern. The purpose of this study was to compare and contrast the relative benefits of word lists that were individualized for these augmented subjects to word lists selected from standard vocabulary sources. Communication samples were collected for 14 consecutive days from 10 subjects who used augmentative and alternative communication (AAC) devices. These samples were analyzed to determine the frequency of single word occurrence, and the results were compared with those obtained from analysis of standard vocabulary lists. The conclusions of the study were (a) that when vocabulary lists are individually created, based on the frequency of word occurrence in natural communication samples, relatively short lists can represent a large proportion of the total communication sample; (b) that individualized word lists are more efficient than standard vocabulary lists, if efficiency is defined as a large proportion of the total sample represented by a small list; and (c) that if used in their entirety, standard lists are not efficient because they contain a large number of words that are rarely used.

Adolescent↗

PubMed1990

Extended communication samples of augmented communicators. II: Analysis of multiword sequences.

The three primary purposes of this project are (a) to identify those word sequences that occur frequently across a group of 10 linguistically intact augmented communicators, (b) to determine the communality with which the various augmented communicators use specific word sequences, and (c) to evaluate the usefulness of word sequences in providing keystroke savings for users of augmentative and alternative communication (AAC) devices as compared to letter-by-letter spelling or single-word retrieval. Communication samples were collected for 14 consecutive days from 10 subjects who used AAC devices. These samples were analyzed with custom software to determine the frequency of occurrence of one-, two-, three-, four-, and five-word sequences. The results revealed that three-, four-, and five-word sequences occurred very infrequently within and across communication samples. Two-word sequences occurred much more frequently than the longer sequences. The authors concluded that clinicians should continue to encourage linguistically intact clients to select long messages (three words or more) for their AAC devices based on message content and the urgency with which messages need to be delivered rather than relying exclusively on statistical analysis. However, statistically based multiword analysis should not be abandoned. Frequently occurring one- and two-word sequences may be an important source of messages that will increase communication efficiency when stored and retrieved in an AAC device.

Adolescent↗

PubMed1990

The effect of rate control on the intelligibility and naturalness of dysarthric speech.

Speaking rates of individuals with severe ataxic dysarthria (n = 4) and severe hypokinetic dysarthria (n = 4) were reduced to 60% and 80% of habitual rates using four different pacing strategies (Additive Metered, Additive Rhythmic, Cued Metered, and Cued Rhythmic). Effects of rate control on sentence and phoneme intelligibility and speech naturalness were examined. Sentence intelligibility improved for both groups, with metered pacing conditions associated with the largest improvement in scores. Similar improvements as speaking rates were reduced were not seen for the phoneme intelligibility task; however, one must recognize that sentence and phoneme intelligibility tasks are different. Slowing the rate of dysarthric speakers did not have as marked an impact on speech naturalness as it did for normal speakers whose naturalness decreased at slowed rates. Metered rate control strategies were associated with the lowest ratings of naturalness for all subject groups. A potential explanation for the discrepancies between the findings for sentence and phoneme intelligibility is offered.

Adult↗

PubMed1989

Perceived articulatory adequacy and velopharyngeal function in dysarthric speakers.

Twenty-four dysarthric speakers with etiologies of brain injury or stroke were placed into one of two groups based on aerodynamic measures of velopharyngeal status. Group I contained 13 individuals who were velopharyngeally incompetent in that nasal air flow was always noted during the stop phase of voiceless plosive sounds. Group II contained 11 individuals who at times achieved complete velopharyngeal closure. Certain measures of perceived articulatory adequacy were found to distinguish between the two groups. Specifically, speakers who were velopharyngeally incompetent produced an articulatory error pattern characterized by better performance for the consonant subcategory nasals-glides than for pressure consonants. Speakers who at times were achieving velopharyngeal closure did not exhibit a marked difference between these two consonant subcategories. Clinical use of measurement of articulatory adequacy as a gross indicator of velopharyngeal competence is suggested and limitations are discussed.

Adolescent↗

PubMed1988

Articulatory adequacy in dysarthric speakers: a comparison of judging formats.

An articulatory inventory was administered to 19 dysarthric adults and scored using two judging formats--phoneme identification and traditional testing. Results indicated that samples judged using the traditional testing format, in which the judge knew the target phoneme, were consistently scored more accurately than those that had been judged using a phoneme identification format, in which the target was not known. Although overall both judging formats were characterized by high inter-rater reliability, the traditional testing format was less reliable than phoneme identification with samples obtained from severely involved speakers. Potential uses of articulatory inventories for dysarthric adults are described.

Adolescent↗

PubMed1987

Speech-muscle visuomotor tracking in dysarthric and nonimpaired speakers.

Assessment of speech-muscle function during nonspeech tasks may provide an important component in the clinical evaluation of speech-motor disorders. Various methodological problems have limited the value of such data in the past. The goal of the present study was to evaluate a set of instrumental, objective procedures for assessment of the nonspeech performance capabilities of different speech-muscle systems. Subjects included 10 nonimpaired adults and a diverse group of 6 adult dysarthric individuals. Each subject performed visuomotor tracking of a 0.6-Hz sinusoidal target with the lower lip, jaw, larynx, and respiratory systems. Cross correlation and phase data were used to describe tracking performance. The nonimpaired subjects showed consistently high cross correlations with little phase shift. The dysarthric subjects showed a wide range of tracking performance which was generally consistent with their overall levels of speech performance and levels of neurological impairment. Differential levels of performance were noted across speech subsystems in some dysarthric subjects. In general, the results suggest that visuomotor-tracking paradigms provide a viable approach to clinical evaluation of speech-muscle function in nonspeech tasks.

Adult↗

PubMed1986

Modification of breath patterning to increase naturalness of a mildly dysarthric speaker.

The case of a 20-year-old, closed head injured male with mild dysarthria is presented. The decreased naturalness of speech was related to short, uniform breath groups, inhalation during every pause, and restricted fundamental frequency. Data related to patterns of breathing and pausing during samples of connected speech along with measures of respiratory control are presented in order to illustrate techniques for assessing and training speech naturalness.

Adult↗

PubMed1985

Communication augmentation systems: quantification in natural settings.

Although observation in clinical settings of communication augmentation system use by severely physically handicapped nonspeaking persons is important, monitoring of such use in natural settings can yield valuable information about the system, communication frequency, and unique communication needs of the individual. This study was designed to evaluate the use of communication partners as data recorders. For nonspeaking, severely physically handicapped subjects were observed in the home, school or treatment settings by a trained observer and a minimally trained communication partner. Issues of partner training and length of time required to obtain a representative sample of communication arose as a result of this study. More work in the areas of automated data collection systems or use of communication partners as data collectors is required before claiming that accurate communication interactions can be recorded in natural settings.

Adolescent↗

PubMed1984

Frequency of word occurrence in communication samples produced by adult communication aid users.

Communication samples generated by five nonspeaking adults using Canon Communicators were collected for 14 consecutive days. Samples were analyzed to determine frequency of word occurrence. A core vocabulary of the 500 most frequently occurring words was analyzed further to determine spelling level and proportion of complete communication samples represented by subsets of the core vocabulary list. The 500 core vocabulary words represented 80% of the total words in the combined communication samples for the 5 subjects. Of all messages generated by the subjects, 33% could be communicated in their entirety using words from the core vocabulary list. The communication of the remaining messages required one or more words in addition to the core vocabulary. The spelling grade level of the words in the core vocabulary list did not exceed the seventh grade. The implications of the results for designing and customizing communication aids and for potential user training are discussed.

Adolescent↗

PubMed1981

Canon communicator use by adults: a retrospective study.

The purpose of this study was to document aspects of successful Canon Communicator use by 13 subjects. Questionnaires were completed by the speech-language pathologists serving these individuals. Subjects ranged in age from 17 to 64 years. They had used the Canon as a communication augmentation device from 2 to 24 months. All were either anarthric or severely dysarthric as a result of a neurological disorder (cerebral palsy, bilateral CVA, closed head injury, ALS) but none were diagnosed as aphasic. The decision to recommend the Canon was made mre rapidly for older adults. Although a majority of the subjects used more than one communication system, all subjects for whom the Canon remained appropriate (11 of 13) continued to use this device more frequently than other systems. No malfunction other than power supply system was reported.

Adolescent↗

PubMed1980

Nonvocal communication: performance evaluation.

With the increasing number of communication options available to severely dysarthric individuals, there is a growing need to develop techniques for the evaluation of nonvocal communication performance. A data collection and analysis system was developed in order to assess the performance of 2 nonvocal communicators. Records of entire messages were obtained along with durational measures of communication partner receiving time for each message, identity of the communication partner and location.

Adult↗

PubMed1979

The relationship between information transfer and speech intelligibility of dysarthric speakers.

The purpose of this study was to determine the relationship between information transfer and speech intelligibility, as measured by single-word and paragraph transcription across a wide range od dysarthric speakers. Nine dysarthric speakers, including ataxic, spastic, and hypokinetic types, participated in the study. Their performance was judged by 108 listeners. The correlations between information transfer and paragraph and transcription scores and between information transfer and word transcription scores were high, i.e., 0.95 and 0.90, respectively. Word transcription scores tended to be slightly lower than information transfer scores for mildly dysarthric speakers. Clinical implications of these findings were discussed.

Adult↗

PubMed1978

A comparison of techniques for measuring intelligibility of dysarthric speech.

Eight techniques for quantifying intelligibility of dysarthric speech were compared. Eight dysarthric speakers who represented a wide range of severity were recorded producing single words and sentences. Thirty-two college students performed the following intelligibility quantification tasks: percentage estimates, rating scale estimates, work and sentence transcriptions, word and sentence completions, and word and sentence multiple-choice tasks. Intelligibility scores for transcriptions were compared to estimates and to other objective tasks with the following results: (1) all measurement techniques, except word completion, rank ordered speakers similarly to transcriptions, (2) mean estimates of intelligibility closely parallel transcription scores, but dispersion of listener estimates was large, and (3) objective tasks form a hierarchy with speakers receiving lowest scores on transcriptions, intermediate scores on completions, and highest scores on multiple-choice tasks. Mean scores for words and sentences were similar. Implications of results for clinical management of dysarthria are discussed.

Adult↗

PubMed1977

Imposed delay of response: effects on aphasics auditory comprehension of visuality and non-visually cued material.

Two groups of aphasics were administered an auditory comprehension task under conditions of 0-, 5-, and 10-sec. imposed delay of response. The auditory-visual group received auditory and visual cues; the auditory group received only auditory cues. Comprehension for the auditory-visual group was significantly better than for the auditory group. Increase in delay time significantly improved comprehension for the auditory-visual group but not for the auditory group.

Adult↗