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Biomedical subjects

A Caramazza

Publications and source records attributed to A Caramazza.

At least 73 records · Page 4Linked to original sources
PubMed1989

The graphemic buffer and attentional mechanisms.

Two patients with acquired dysgraphia were reported. The patients' performance in various written and oral spelling tasks converge in support of the hypothesis that they have selective damage, within the spelling system, to the Graphemic Buffer. Although the patients present with comparable patterns of error types, they differ in the distribution of errors as a function of letter position in words. The patients' patterns of errors are compared to previously reported patterns of spelling errors in dysgraphic patients and are discussed in terms of hypothesized mechanisms that operate on the representations that are stored in the Graphemic Buffer.

Agraphia↗
PubMed1989

Variation in the pattern of omissions and substitutions of grammatical morphemes in the spontaneous speech of so-called agrammatic patients.

We describe the patterns of omissions (and substitutions) of freestanding grammatical morphemes and the patterns of substitutions of bound grammatical morphemes in 20 so-called agrammatic patients. Extreme variation was observed in the patterns of omissions and substitutions of grammatical morphemes, both in terms of the distribution of errors for different grammatical morphemes as well as in terms of the distribution of omissions versus substitutions. Results are discussed in the context of current debates concerning the possibility of a theoretically motivated distinction between the clinical categories of agrammatism and paragrammatism and, more generally, concerning the theoretical usefulness of any clinical category. The conclusion is reached that the observed heterogeneity in the production of grammatical morphemes among putatively agrammatic patients renders the clinical category of agrammatism, and by extension all other clinical categories from the classical classification scheme (e.g., Broca's aphasia, Wernicke's aphasia, and so forth) to more recent classificatory attempts (e.g., surface dyslexia, deep dysgraphia, and so forth), theoretically useless.

Adult↗
PubMed1989

The disruption of sentence production: some dissociations.

A patient (M.L.) with selective disruption of sentence production is described. M.L.'s sentence production performance is characterized by the omission (and occasional substitution) of free-standing and bound grammatical morphemes. In contrast to her impaired sentence production performance, M.L. has no difficulties in sentence comprehension or production of single words including functors. Her performance is interpreted as reflecting a functional lesion to the positional level of sentence production.

Agraphia↗
PubMed1989

Patient classification in neuropsychological research.

In a number of papers we have been concerned with the type of inferences that are legitimate in "experiments of nature" where the experimenter does not and cannot control the modifications to the cognitive system that are introduced by brain damage. We have argued that in such cases very restrictive conditions must be met in order to be able to draw valid inferences about the structure of normal cognitive mechanisms. Two consequences of these conditions are (1) patient classification into syndrome types (e.g., phonological dysgraphia, agrammatism, and so forth) can play no useful role in research concerned with issues about the structure of normal cognitive functioning or its dissolution under conditions of brain damage; and (2) only single-patient studies allow valid inferences about the structure of cognitive mechanisms from the analysis of impaired performance. Zurif, Gardner, and Brownell (1989, Brain and Cognition, 10, 237-255) have taken exception to our conclusions and propose to show the limitations of our arguments. In this paper we respond to their criticisms.

Aphasia↗
PubMed1988

When is enough, enough? A comment on Grodzinsky and Marek's "Algorithmic and heuristic processes revisited".

In this comment I argue that although Y. Grodzinsky & A. Marek's (1983, Brain and Language, 33, 216-225) criticism of the conclusions reached by A. Caramazza and E. B. Zurif (1976, Brain and Language, 3, 572-582) in their paper on comprehension disorders in so-called agrammatic patients is not entirely without technical merit, its impact on the claims made by Caramazza and Zurif is inconsequential. I show that there are deeper theoretical and methodological reasons which undermine the claims made by Caramazza and Zurif and the only superficially different proposal of Grodzinsky and Marek.

Algorithms↗
PubMed1988

Dissociation of inflectional and derivational morphology.

A patient is described who makes morphological errors in spontaneous sentence production and in repetition of single words. The great majority of these errors were substitutions of inflectional affixes. The patient did make some derivational errors in repeating derived words but almost never made such errors for nonderived words. The inflectional errors for adjectives and nouns occurred mostly on the plural forms for nouns and adjectives and on the feminine form for adjectives. For verbs, inflectional errors were produced for all tense, aspect, and mood forms. There were no indications that these latter verb features constrained the form of inflectional errors produced. The results are interpreted as support for the thesis that morphological processes are located in the lexicon but that inflectional and derivational processes constitute autonomous subcomponents of the lexicon.

Aphasia↗
PubMed1987

The analysis of morphological errors in a case of acquired dyslexia.

An issue that is persistently raised in studies of subjects who produce morphological errors in reading and other tasks is whether these errors are the consequence of a morphological processing deficit, or whether they in any way reflect morphological principles of organization in the lexicon. We discuss the performance of one such subject on a number of tasks and evaluate standard arguments for attributing aspects of his performance to a morphological processing deficit. Although there are several features of his performance that are suggestive in this regard; we argue that, when these issues are addressed in the context of a sufficiently elaborated theory of lexical processing, a morphological processing deficit cannot be demonstrated. We also survey a number of recent reports that purport to provide evidence for a morphological processing deficit and argue that, in most cases, they fail to support such claims for similar reasons. An important moral to be drawn from a critique of these studies is that in order to make valid inferences concerning the role of morphology in organizing the lexicon, we must consider these errors in the context of theories of the lexicon that take seriously the effects of converging lexical factors in processing.

Adult↗
PubMed1987

Patterns of dysgraphia and the nonlexical spelling process.

This article evaluates the hypothesis that phoneme-grapheme conversion is accomplished by a passive activation device in which the selection of mapping options in the process of assembling orthography is determined by the frequency of usage of that option in the language. The spelling performance of two brain-damaged, acquired dysgraphic patients is interpreted as support for the stated hypothesis.

Agraphia↗
PubMed1986

On drawing inferences about the structure of normal cognitive systems from the analysis of patterns of impaired performance: the case for single-patient studies.

An analysis of the logic of valid inferences about the structure of normal cognitive processes from the study of impaired cognitive performance in brain-damaged patients is presented. The logic of inferences from group studies and single-case studies is compared. It is shown that given certain assumptions, only the single-case method allows valid inferences about the structure of cognitive systems from the analysis of impaired performance. It is also argued that although the single-case approach is not entirely problem-free, the difficulties encountered are relatively minor.

Brain Damage, Chronic↗
PubMed1985

Cognitive analysis of a case of pure dysgraphia.

An Italian patient with a pure dysgraphia who incorrectly spelled words and nonwords is described. The spelling errors made by the patient were not affected by lexical factors (e.g., frequency, form class) and were qualitatively the same for words and nonwords. The pattern of writing performance is discussed in relation to current models of writing and, specifically, in relation to the role of the Output Grapheme Buffer and Phoneme-Grapheme Conversion in writing.

Cerebrovascular Disorders↗
PubMed1985

Cognitive mechanisms in number processing and calculation: evidence from dyscalculia.

This article presents a framework for the cognitive analysis of number processing and calculation. Within this framework the primary objective is the development of a model that is sufficiently detailed to serve as a basis for explaining the number-processing/calculation performance of both normal and cognitively impaired subjects. First a general model of the cognitive mechanisms for number processing and calculation is outlined. It is shown that patterns of impairments observed in brain-damaged patients support the major assumptions of the model and that the model provides a theoretically motivated framework for interpreting the deficits. A single case is then discussed in some detail, to demonstrate that through detailed analyses of impaired performance the preliminary model can be elaborated to specify not only the general architecture of the number-processing and calculation systems, but also the inner workings of specific components and the consequences of damage to these components. The article concludes with a discussion of several general issues arising from the presented arguments.

Anomia↗