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Biomedical subjects

T P Marquardt

Publications and source records attributed to T P Marquardt.

13 recordsLinked to original sources
PubMed1999

A comparison of the codeswitching patterns of aphasic and neurologically normal bilingual speakers of English and Spanish.

Conversational discourse samples were obtained from four aphasic and four neurologically normal Hispanic bilinguals in monolingual English, monolingual Spanish, and bilingual contexts to identify codeswitching patterns. Analysis of the samples based on the Matrix Language Frame (MLF) Model (Myers-Scotton, 1993a) revealed consistent matching of the language context by the aphasic and normal subjects. The aphasic subjects demonstrated a greater frequency of MLF constituents and codeswitching patterns not evident in the speech samples of the normal subjects. Results suggest an increased dependence on both languages for communication following neurological impairment.

Adult↗
PubMed1993

The perception and production of rhyme in normal and developmentally apraxic children.

The phonological competence of four children, aged 5-7 years old, who demonstrated a cluster of symptoms consistent with a diagnosis of developmental apraxia of speech (DAS), was contrasted to that of four normal children. Four rhyming tasks were used to assess the ability of the children to both spontaneously generate rhyming words to targets and to judge the (in)appropriateness of a rhyme in both a word series and forced-choice word pairs. The DAS children revealed a severe deficit in rhyming ability across all tasks and had rhyming abilities markedly inferior to those shown by normal children. The rhyming results were interpreted as possibly indicative of an impoverishment of an internalized phonemic representation system, which precludes accessing and evoking the needed sound image for the vowel + coda for a rhyme. These results, while preliminary in nature, lend support to a conceptualization of DAS as a fundamental disorder of the segmental phonological level of language that impacts on all hierarchically relevant language components. The hypothesis that the underlying etiology of DAS is a developmental dysmorphology of the neural substrates that mediate such basic phonological representational structure is discussed.

Apraxias↗
PubMed1988

Speech intelligibility of two voice output communication aids.

The purpose of the study was to investigate the intelligibility of two voice output communication aids. Twenty words and 20 sentences, synthesized with the Personal Communicator and with the SpeechPAC, were presented to 20 listeners. Listener transcriptions of the stimuli were used to compare the intelligibility of the two communication aids. Analysis of variance revealed significantly higher intelligibility scores for the Personal Communicator compared to the SpeechPAC and higher scores for sentences than for words. The implications of these findings for selection of augmentative communication devices is discussed.

Adult↗
PubMed1987

Aerodynamic control in apraxia at three intraoral pressure levels.

Five neurologically normal and five apractic subjects were required to develop and maintain target intraoral pressure levels during 5-sec. trials. The apractic subjects showed increased latencies in gaining the target and reduced maintenance time and increased variability in attempts to stay at target. Results suggest that physiologically based assessment tasks provide sensitive indices of the degree of oral apraxia in patients with left-hemisphere brain damage.

Aphasia↗
PubMed1985

Communicative effectiveness in Broca's aphasia.

The purpose of this study was to investigate communicative effectiveness in aphasia. Five patients with Broca's aphasia and five neurologically normal subjects participated in referential communication and spontaneous conversation tasks. Performance on the referential tasks was used to derive measures of communication success, learning, and efficiency. A representative sample of utterances from the referential tasks and 100 utterances from the spontaneous conversation task also were analyzed to determine the frequency of operationally defined errors in speech, lexical access, grammar, content, discourse, and use. Results suggest that patients with Broca's aphasia retain communicative effectiveness in the presence of significant speech and language deficits and experimentally imposed constraints on the use of visual and gestural communication modalities.

Adult↗
PubMed1984

Pantomime in aphasia: effects of stimulus characteristics.

The effects of three types of stimuli (objects, line drawings, action pictures) on the comprehension and production of pantomimes in aphasic patients were assessed. A significantly higher number of correct pantomime responses was found for objects and action pictures than for line drawings. Significant positive correlations were found between aphasia subtest scores and pantomimic scores. The theoretical and clinical implications of these findings are discussed.

Aphasia↗
PubMed1979

Markedness analysis of phonemic substitution errors in apraxia of speech.

The phonemic substitution errors of ten apractic speakers were analyzed to investigate the effects of markedness on speech production patterns. Results revealed that: more errors were produced on phonemes high in markedness; more changes in markedness were from marked to unmarked than unmarked to marked; and errors and directional changes in markedness were positively correlated with ease of articulation. The findings were interpreted as a systematic effort by the apractic speakers to reduce the complexity of articulatory gestures required to produce phonemes.

Aged↗
PubMed1977

Linguistic and articulatory aspects of single word production in apraxia of speech.

The errors of ten apraxic speakers on a single word task were analyzed to determine the effects of articulatory and linguistic variables on speech production. Results suggested that phoneme difficulty but not phoneme position or grammatical class significantly affected the errors of the subjects. A significant low positive correlation between mean word abstraction and the errors of the apraxic speakers was observed although correlations for the grammatical classes decreased with increases in abstraction. These findings were interpreted to suggest that impaired motor speech programming may be affected by linguistic and articulatory variables.

Adult↗
PubMed1977

Effects of selected linguistic variables on apraxia of speech.

Ten adults with apraxia of speech responded to sentences of an article (pronoun) + noun + verb + article (pronoun) + noun design. Each sentence was presented and then re-presented with the noun in Noun Phrase 1 (NP1) or Noun Phrase 2 (NP2) omitted. The subjects' task was to orally produce the omitted word. Sentences were either active or passive and the omitted noun was a concrete, abstract, or nonsense word. Results revealed significantly more errors in NP1 than NP2, more errors on nonsense and abstract nouns than on concrete nouns, and more errors on passive than on active voice sentences. Linguistic bases for these findings are discussed.

Adult↗