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Biomedical subjects

T F Campbell

Publications and source records attributed to T F Campbell.

9 recordsLinked to original sources
PubMed1995

Speaking rate, articulatory speed, and linguistic processing in children and adolescents with severe traumatic brain injury.

Two studies were conducted to examine speaking rate following traumatic brain injury (TBI) in childhood and adolescence. Study 1 focused on longitudinal changes in speaking rate in 9 subjects with severe TBI and their age-matched control subjects. Physical measurements of speaking rate (in syllables/sec) were made from spontaneous speech samples obtained from each subject during three sampling sessions over a 13-month period. Although the average speaking rate of the group with TBI was slower than that of the control group at all three sampling sessions, an examination of the data from individual subject pairs revealed markedly slower speaking rates in only 5 of the 9 subjects with TBI at the final sampling session. The perceptual significance of slowed speaking rates in these 5 subjects was confirmed through subjective ratings by naive listeners. In Study 2, the contributions of two potential causes of slowed speaking rate were explored: reduced articulatory speed and increased pausing believed to be associated with linguistic processing difficulties. It is hypothesized that articulatory speed and linguistic processing speed may contribute independently to slowed speaking rates more than 1 year after TBI.

Adolescent↗
PubMed1991

Pediatric voice disorders.

Voice disorders are common among children, estimated to range from 6% to 23% in school-aged children. The various causes of voice disorders are presented in this article in addition to a discussion of normal laryngeal voice and development. Also presented are the causes of abnormal voice and brief discussion of a framework for multidisciplinary assessment and treatment of pediatric voice disorder.

Child↗
PubMed1990

Expressive language recovery in severely brain-injured children and adolescents.

The spontaneous expressive language abilities of 9 severely brain-injured children and adolescents and their age-matched normal controls were examined seven times over a 12-month period following injury. Analysis of conversational language samples revealed a relatively stable pattern of language performance for the normal subjects over this time interval. The brain-injured subjects, as a group, demonstrated improvement on the majority of measures, but only a few reached the level of their control subjects and interindividual variability was considerable. Results suggest that the prognosis for clinically significant improvement in severely brain-injured subjects is good; however, deficits in expressive skills remain apparent up to at least 12 months following injury.

Adolescent↗
PubMed1990

Video narration as a language sampling context.

Video narration is a context for sampling spontaneous expressive language in which the subject produces an on-line description of the events he or she observes on videotape. Video narration offers a means of reducing the variability among language samples from different speakers, or from the same speaker over time, because the number and complexity of events to be coded linguistically is known and constant. This increased consistency facilitates comparisons among samples, as well as enabling certain analyses requiring a transparent relationship between utterances and events. Advantages and limitations of video narration as an adjunct to conversational sampling are described, and comparisons between longitudinal video narration and conversational samples obtained from brain-injured children and their matched normal controls are presented.

Adolescent↗
PubMed1989

A signal processing component to Broca's aphasia functor deficits.

We conducted a modified replication of K. M. Heilman and R. J. Scholes [Cortex 12, 258-265, 1976] test of functor comprehension in aphasia, controlling the acoustic dimensions of the key function words: 9 Broca patients heard 4 sentence pairs differing only in the post-verb placement of the. They made forced choices between 4 line drawings: one which depicted the correct action, one which depicted the action of the other member in the pair, and two which contained depictions of different figures and actions altogether. Each of the 8 sentences was played in 2 conditions: one with NORMAL intonation, and another with an acoustically more SALIENT post-verbal the. Both of Heilman and Scholes' principal results were successfully replicated, and a SALIENT effect was also discovered, supporting a signal processing component to the Broca syndrome functor deficit.

Aphasia↗
PubMed1985

Effects of presentation rate and divided attention on auditory comprehension in children with an acquired language disorder.

We examined why auditory comprehension in language-disordered children improves when the rate of presentation of speech is slowed. Seven children with an acquired language disorder associated with a convulsive disorder participated in two divided-attention tasks in which pairs of sentences were presented simultaneously. Subjects were instructed to respond first to the sentence produced by a male speaker (primary sentence) and then to the sentence produced by a female speaker (secondary sentence). In the first condition, both sentences were presented at a normal rate of speech. In the second condition, primary sentences were time expanded 75%, and secondary sentences were presented at a normal rate. We hypothesized that when the primary sentences were presented slowly, spare attention would be available for processing the secondary sentences. Results showed that slowing the presentation rate of the primary sentences significantly improved performance on the secondary sentences, even though secondary sentences were presented at a normal rate of speech. Hypotheses of generally slowed processing of auditory information in language-disordered individuals cannot account for these results. They are consistent, however, with a model of defective attention allocation.

Attention↗
PubMed1977

Automatization of correct production at two levels of articulatory acquisition.

This study investigated the assumption that children who are in the process of acquiring correct production of a misarticulated phoneme are also in the process of developing automatization of correct production. Using the McDonald Deep Test of Articulation, children's articulation was tested under two conditions: Condition 1 without masking and Condition 2 with 85 dB SLP of competing speech masking. Children were classified into one of two levels of articulatory acquisition according to their performance during Condition 1. Children scoring below 80% correct were classsified as demonstrating low acquisition. Children scoring above 80% correct were classified as demonstrating high acquisition. Only children with /s/ or /r/ misarticulations were studied. Results indicated that the correct articulation of children demonstrating low acquisition was significantly more affected by the auditory masking than the correct articulation of those children demonstrating higher levels of acquisition. There was no significant difference in the performance of the children with the /s/ or /r/ misarticulations. The results support the concept that articulatory acquisition and automatization of correct articulation relate in a predictable manner.

Age Factors↗