Biomedical subjects

D A Gagnon

Publications and source records attributed to D A Gagnon.

6 recordsLinked to original sources

PubMed2001

Prenatal care needs, availability, accessibility, use, and satisfaction: a comparison of military women within and outside the continental United States.

This article presents the results of a survey distributed to military women within and outside the continental United States (CONUS and OCONUS) who had received prenatal care and delivered at one of six Army, Navy, or Air Force military facilities. This comparative descriptive study was undertaken to determine from the mothers' perspective (1) their needs, availability, accessibility, use, satisfaction, and preferences for prenatal care services, and (2) if prenatal care and birth outcomes were significantly different for CONUS versus OCONUS women. Both groups reported a high degree of satisfaction with services, clinics/offices, and health care staff. Significant group differences were reported in transportation, length of travel time, and cost of traveling, with the CONUS group reporting greater problems with each. For both groups, quality and consistency of health care were the two most important factors in their preference of provider. More than 20% of the mothers reported receiving no information on some of the common concerns of pregnancy. There were no significant group differences with regard to infant birth weight or length of hospital stay.

Adult↗

PubMed2000

The role of computational models in neuropsychological investigations of language: reply to Ruml and Caramazza (2000).

W. Ruml and A. Caramazza's (2000) analysis of the model of normal and aphasic lexical access proposed by G. S. Dell, M. F. Schwartz, N. Martin, E. M. Saffran, and D. A. Gagnon (1997) is completely at odds with current practice concerning the use of models in psychology. An evaluation of Dell et al.'s original claims using Ruml and Caramazza's model parameters sustains these claims in all respects.

Aphasia↗

PubMed1997

The origins of formal paraphasias in aphasics' picture naming.

Accounts of spoken word production differ on whether aphasics' formal paraphasias derive solely from segmental distortion or whether some derive instead from whole word substitution. Form-related paraphasias produced by nine aphasics during picture naming were examined for evidence of lexical effects (word, frequency, and grammatical class biases) and for the manner in which target phonemes and word shape were preserved. Preservation patterns were consistent with previous descriptions of aphasic and nonaphasic form-related speech errors. Evidence for word and frequency biases was found, as well as a grammatical class bias sensitive to the degree of target-response segmental overlap. In conjunction, the results indicate that formal paraphasias arise, at least in part, via word substitution. The findings are supportive of interactive models with phonological-to-lemma feedback and/or modular models with a grammatically organized lexeme level.

Adult↗

PubMed1997

Lexical access in aphasic and nonaphasic speakers.

An interactive 2-step theory of lexical retrieval was applied to the picture-naming error patterns of aphasic and nonaphasic speakers. The theory uses spreading activation in a lexical network to accomplish the mapping between the conceptual representation of an object and the phonological form of the word naming the object. A model developed from the theory was parameterized to fit normal error patterns. It was then "lesioned" by globally altering its connection weight, decay rates, or both to provide fits to the error patterns of 21 fluent aphasic patients. These fits were then used to derive predictions about the influence of syntactic categories on patient errors, the effect of phonology on semantic errors, error patterns after recovery, and patient performance on a single-word repetition task. The predictions were confirmed. It is argued that simple quantitative alterations to a normal processing model can explain much of the variety among patient patterns in naming.

Adult↗

PubMed1995

Auditory coding, cues, and coherence in phonetic perception.

C. T. Best, M. Studdert-Kennedy, S. Manuel, and J. Rubin-Spitz (1989) reported that listeners given speech labels showed categorical-like perception of a series of complex tone analogs to a /la/-/ra/ speech series, whereas nonspeech listeners were unable to classify the stimuli consistently. In 2 experiments, a new training and testing procedure was used with adult listeners given nonspeech instructions. They classified the /la/-/ra/ tone analogs consistently, showed categorical-like perception, and generalized their training to a new, /li/-/ri/ tone analog series. Two sets of auditory attributes were described for coding the /l/-/r/ distinction, and 1 was shown to quantitatively predict listeners' classification of both series. These results are consistent with models of perception in which a rich, abstract auditory code is computed and forms the basis for both speech and nonspeech auditory categories.

Adult↗

PubMed1992

Information tradeoffs in complex stimulus structure: local and global levels in naturalistic scenes.

An information tradeoff is an increased processing or utilization of information from one stimulus source at the expense of processing or utilization of information from a different source. An experiment was conducted to determine whether information tradeoffs occurred when subjects attended selectively to one of two different structural levels of naturalistic scenes. The subjects' attentional focus was directed to either the global or local structure of a scene (i.e., the scene or an object in the scene, respectively) either before or after presentation of a scene. They then had to use the information obtained from a 100-msec exposure of the scene to choose between two forced-choice alternatives that described one of the levels. The nature of the alternatives was such that both alternatives adequately characterized one of the structural levels on the basis of physical and semantic relations within the scene. Results showed that the subjects were significantly slower and less accurate when their attentional focus and the forced-choice alternatives were at different levels of stimulus structure than when they were at the same level, providing evidence of an information tradeoff when different types of information from a scene were used. When processing information from a particular structural level, information from the other level either was less available or was not used efficiently. Furthermore, the information tradeoffs were more severe in the precue than in the postcue condition, indicating differences in the efficiency of the selectivity process. The results are interpreted with respect to the role of selective attention in processing complex stimuli such as naturalistic scenes.

Adult↗