45 results on '"Saffran EM"'
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2. Knowledge of object manipulation and object function: dissociations in apraxic and nonapraxic subjects.
- Author
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Buxbaum LJ, Saffran EM, Buxbaum, Laurel J, and Saffran, Eleanor M
- Abstract
An influential account of selective semantic deficits posits that visual features are heavily weighted in the representations of animals, whereas information about function is central in the representations of tools (e.g., Warrington & Shallice, 1984 ). An alternative account proposes that information about all types of objects-animate and inanimate alike-is represented in a distributed semantic architecture by verbal-propositional, tactile, visual, and proprioceptive-motor nodes, reflecting the degree to which these systems were activated when the knowledge was acquired (e.g., Allport, 1985 ). We studied a group of left hemisphere chronic stroke patients, some of whom were apraxic, with measures of declarative tool and animal knowledge, body part knowledge, and function and manipulation knowledge of artifacts. Apraxic (n=7) and nonapraxic (n=6) subjects demonstrated a double dissociation of performance on tests of tool and animal knowledge, suggesting that the apraxic group was not simply more severely impaired overall. Apraxics were relatively impaired in manipulation knowledge, whereas nonapraxics tended to be relatively impaired in function knowledge. Apraxics were also more impaired with body parts than nonapraxics. The association of gestural praxis, tool knowledge, body part knowledge, and manipulation knowledge suggests a coherent basis for the organization of semantic artifact knowledge in frontoparietal cortical regions specialized for sensorimotor functions, and thus provides support for the distributed architecture account of the semantic system. [ABSTRACT FROM AUTHOR]
- Published
- 2002
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3. How is your B-A-B-Y? Dissociated oral and written production.
- Author
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Saffran EM, Coslett HB, and DeSalme EJF
- Published
- 2000
4. Narrowing the spotlight: a visual attentional disorder in presumed Alzheimer's disease.
- Author
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Coslett HB, Stark M, Rajaram S, and Saffran EM
- Published
- 1995
5. Distinctions between manipulation and function knowledge of objects: evidence from functional magnetic resonance imaging.
- Author
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Boronat CB, Buxbaum LJ, Coslett HB, Tang K, Saffran EM, Kimberg DY, and Detre JA
- Subjects
- Adult, Apraxias physiopathology, Brain Mapping, Female, Humans, Male, Memory physiology, Photic Stimulation, Reaction Time physiology, Cognition physiology, Form Perception physiology, Magnetic Resonance Imaging
- Abstract
A prominent account of conceptual knowledge proposes that information is distributed over visual, tactile, auditory, motor and verbal-declarative attribute domains to the degree to which these features were activated when the knowledge was acquired [D.A. Allport, Distributed memory, modular subsystems and dysphagia, In: S.K. Newman, R. Epstein (Eds.), Current perspectives in dysphagia, Churchill Livingstone, Edinburgh, 1985, pp. 32-60]. A corollary is that when drawing upon this knowledge (e.g., to answer questions), particular aspects of this distributed information is re-activated as a function of the requirements of the task at hand [L.J. Buxbaum, E.M. Saffran, Knowledge of object manipulation and object function: dissociations in apraxic and non-apraxic subjects. Brain and Language, 82 (2002) 179-199; L.J. Buxbaum, T. Veramonti, M.F. Schwartz, Function and manipulation tool knowledge in apraxia: knowing 'what for' but not 'how', Neurocase, 6 (2000) 83-97; W. Simmons, L. Barsalou, The similarity-in-topography principle: Reconciling theories of conceptual deficits, Cognitive Neuropsychology, 20 (2003) 451-486]. This account predicts that answering questions about object manipulation should activate brain regions previously identified as components of the distributed sensory-motor system involved in object use, whereas answering questions about object function (that is, the purpose that it serves) should activate regions identified as components of the systems supporting verbal-declarative features. These predictions were tested in a functional magnetic resonance imaging (fMRI) study in which 15 participants viewed picture or word pairs denoting manipulable objects and determined whether the objects are manipulated similarly (M condition) or serve the same function (F condition). Significantly greater and more extensive activations in the left inferior parietal lobe bordering the intraparietal sulcus were seen in the M condition with pictures and, to a lesser degree, words. These findings are consistent with the known role of this region in skilled object use [K.M. Heilman, L.J. Gonzalez Rothi, Apraxia, In: K.M. Heilman, E. Valenstein (Eds.), Clinical Neuropsychology, Oxford University Press, New York, 1993, pp. 141-150] as well as previous fMRI results [M. Kellenbach, M. Brett, K. Patterson, Actions speak louder than functions: the importance of manipulability and action in tool representation, Journal of Cognitive Neuroscience, 15 (2003) 30-46] and behavioral findings in brain-lesion patients [L.J. Buxbaum, E.M. Saffran, Knowledge of object manipulation and object function: dissociations in apraxic and non-apraxic subjects, Brain and Language, 82 (2002) 179-199]. No brain regions were significantly more activated in the F than M condition. These data suggest that brain regions specialized for sensory-motor function are a critical component of distributed representations of manipulable objects.
- Published
- 2005
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6. Contrasting effects of phonological priming in aphasic word production.
- Author
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Wilshire CE and Saffran EM
- Subjects
- Anomia diagnosis, Aphasia, Wernicke diagnosis, Cerebral Hemorrhage complications, Cerebral Hemorrhage diagnosis, Cerebral Hemorrhage psychology, Cerebral Infarction complications, Cerebral Infarction diagnosis, Cerebral Infarction psychology, Female, Humans, Male, Middle Aged, Neuropsychological Tests, Serial Learning, Verbal Behavior, Anomia psychology, Aphasia, Wernicke psychology, Attention, Paired-Associate Learning, Pattern Recognition, Visual, Phonetics
- Abstract
Two fluent aphasics, IG and GL, performed a phonological priming task in which they repeated an auditory prime then named a target picture. The two patients both had selective deficits in word production: they were at or near ceiling on lexical comprehension tasks, but were significantly impaired in picture naming. IG's naming errors included both semantic and phonemic paraphasias, as well as failures to respond, whereas GL's errors were mainly phonemic and formal paraphasias. The two patients responded very differently to phonological priming: IG's naming was facilitated (both accuracy and speed) only by begin-related primes (e.g. ferry-feather), whereas GL benefited significantly only from end-related primes (e.g. brother-feather), showing no more than a facilitatory trend with begin-related primes. We interpret these results within a two-stage model of word production, in which begin-related and end-related primes are said to operate at different stages. We then discuss implications for models of normal and aphasic word production in general and particularly with respect to sequential aspects of the phonological encoding process.
- Published
- 2005
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7. Differences in word associations to pictures and words.
- Author
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Saffran EM, Coslett HB, and Keener MT
- Subjects
- Adult, Female, Humans, Male, Mental Processes physiology, Mental Recall, Middle Aged, Reaction Time, Reference Values, Semantics, Word Association Tests, Association Learning, Form Perception, Pattern Recognition, Visual, Reading, Verbal Behavior
- Abstract
Normal subjects were asked to produce the "first word that comes to mind" in response to pictures or words that differed with respect to manipulability and animacy. In separate analyses across subjects and items, normal subjects produced a significantly higher proportion of action words (that is, verbs) to pictures as compared to words, to manipulable as compared to non-manipulable stimuli and to inanimate as compared to animate stimuli. The largest proportion of action words was elicited by pictures of non-living, manipulable objects. Furthermore, associates to words matched standard word associates significantly more often than those elicited by pictures. These data suggest that pictures and words initially contact different forms of conceptual information and are consistent with an account of semantic organization that assumes that information is distributed across different domains reflecting the mode of acquisition of that knowledge.
- Published
- 2003
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8. Knowledge of the human body: a distinct semantic domain.
- Author
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Coslett HB, Saffran EM, and Schwoebel J
- Subjects
- Atrophy, Dementia psychology, Female, Humans, Magnetic Resonance Imaging, Middle Aged, Temporal Lobe pathology, Body Image, Dementia pathology, Knowledge, Semantics
- Abstract
Background: Patients with selective deficits in the naming and comprehension of animals, plants, and artifacts have been reported. These descriptions of specific semantic category deficits have contributed substantially to the understanding of the architecture of semantic representations., Objective: This study sought to further understanding of the organization of the semantic system by demonstrating that another semantic category, knowledge of the human body, may be selectively preserved., Methods: The performance of a patient with semantic dementia was compared with the performance of healthy controls on a variety of tasks assessing distinct types of body representations, including the body schema, body image, and body structural description., Results: Despite substantial deficits on tasks involving language and knowledge of the world generally, the patient performed normally on all tests of body knowledge except body part naming; even in this naming task, however, her performance with body parts was significantly better than on artifacts., Conclusions: The demonstration that body knowledge may be preserved despite substantial semantic deficits involving other types of semantic information argues that body knowledge is a distinct and dissociable semantic category. These data are interpreted as support for a model of semantics that proposes that knowledge is distributed across different cortical regions reflecting the manner in which the information was acquired.
- Published
- 2002
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9. The role of computational models in neuropsychological investigations of language: reply to Ruml and Caramazza (2000).
- Author
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Dell GS, Schwartz MF, Martin N, Saffran EM, and Gagnon DA
- Subjects
- Humans, Neurophysiology, Reproducibility of Results, Aphasia, Language, Models, Psychological
- Abstract
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.
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- 2000
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10. Quantitative analysis of aphasic sentence production: further development and new data.
- Author
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Rochon E, Saffran EM, Berndt RS, and Schwartz MF
- Subjects
- Adult, Aged, Cluster Analysis, Factor Analysis, Statistical, Female, Humans, Linguistics, Male, Middle Aged, Reproducibility of Results, Time Factors, Aphasia, Broca diagnosis, Verbal Behavior physiology
- Abstract
The narrative production of patients with Broca's aphasia and age-and education-matched control subjects was analyzed using the Quantitative Production Analysis (Saffran et al., 1989), a procedure designed to provide measures of morphological and structural characteristics of aphasic production. In addition to providing data for a larger number of subjects than in the original study, we provide data on interrater and test-retest reliability. The data were also submitted to factor and cluster analyses. Two factors characterized the data and the cluster analysis yielded four sets of patients who performed differently on these factors. In particular, there is evidence that agrammatic patients can differ in their production of free and bound grammatical morphemes, substantiating earlier claims in the literature., (Copyright 2000 Academic Press.)
- Published
- 2000
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11. The organization of semantic memory: in support of a distributed model.
- Author
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Saffran EM
- Subjects
- Aphasia physiopathology, Brain physiopathology, Humans, Memory physiology, Semantics
- Published
- 2000
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12. Aphasia and the relationship of language and brain.
- Author
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Saffran EM
- Subjects
- Aphasia psychology, Humans, Aphasia physiopathology, Cerebral Cortex physiopathology, Language
- Abstract
This article provides a brief history of the study of aphasia, along with current data on aphasic syndromes and their localization in the brain as well as information on testing procedures. A brief examination of language from a functional perspective is also provided, as it is difficult to understand the breakdown patterns without an appreciation for the complexities of language processing per se.
- Published
- 2000
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13. Sentence processing in the face of semantic loss: a case study.
- Author
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Breedin S and Saffran EM
- Subjects
- Atrophy diagnostic imaging, Brain Diseases diagnostic imaging, Humans, Male, Middle Aged, Models, Psychological, Neuropsychological Tests, Temporal Lobe diagnostic imaging, Temporal Lobe pathology, Tomography, Emission-Computed, Single-Photon, Brain Diseases complications, Brain Diseases psychology, Cognition Disorders etiology, Language Disorders etiology, Semantics, Temporal Lobe blood supply
- Abstract
The modularity of the sentence processor, or lack thereof, remains a much-debated issue in psycholinguistics. The authors present evidence from a semantically impaired patient (DM) that bears on this issue. As demonstrated elsewhere (S. D. Breedin, E. M. Saffran, & H. B. Coslett, 1994), DM suffered a significant loss of semantic knowledge. Here, the authors show that this impairment did not compromise DM's ability to process syntactic information. DM performed well on grammaticality judgment tasks and on sentence comprehension tasks that required the use of syntactic information for the assignment of thematic roles. The resistance of syntactic operations to semantic loss would seem to pose a challenge for models in which "the syntactic and conceptual aspects of processing are ... inextricably intertwined" (J. L. McClelland, M. St. John, & R. Taraban, 1989, p. 329).
- Published
- 1999
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14. Semantic factors in verb retrieval: an effect of complexity.
- Author
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Breedin SD, Saffran EM, and Schwartz MF
- Subjects
- Aphasia rehabilitation, Female, Humans, Male, Middle Aged, Psycholinguistics, Psychological Theory, United States, Aphasia psychology, Semantics
- Abstract
Aphasic patients often have more difficulty retrieving verbs than nouns. We present data from eight aphasics demonstrating that they have a selective impairment for verb retrieval. We then explore the role of semantic complexity (i.e., the number of semantic features) in verb retrieval using a delayed repetition/story completion task. The results indicate that six of the patients are better at retrieving semantically complex verbs (e.g., run) than semantically simpler verbs (e.g., go). The results have implications for accounts of the noun/verb dissociation in aphasia, as well as for theories of verb representation., (Copyright 1998 Academic Press.)
- Published
- 1998
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15. Semantic influences on thematic role assignment: evidence from normals and aphasics.
- Author
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Saffran EM, Schwartz MF, and Linebarger MC
- Subjects
- Aged, Female, Humans, Male, Middle Aged, Reaction Time, Aphasia diagnosis, Semantics, Speech physiology
- Abstract
We report two studies that examine the role of semantic influences in the assignment of thematic roles. Semantic factors were manipulated by contrasting sentences in which one noun argument was a plausible filler of only one thematic role (e.g., the painting in The artist disliked the painting) with sentences in which both noun arguments were plausible fillers of both thematic roles (e.g., The robin ate the insect). Subjects were required to make plausibility judgments to sentences presented auditorily. Experiment 1 examined RTs of normal subjects on the plausibility judgment task. In Experiment 2, the same sentences were presented to aphasic patients identified as "asyntactic" comprehenders. In Experiment 1, RTs were speeded by semantic constraints on thematic assignment, particularly when the role-constrained NP occurred early in the sentence (as in The painting was disliked by the artist). The aphasic performance patterns in Experiment 2 paralleled those of normal subjects, but in greatly exaggerated fashion. The patients exhibited high error rates on sentences where semantic constraints conflicted with the syntactically based assignments, even on sentences with canonical (S-V-O) word order (e.g., #The deer shot the hunter)., (Copyright 1998 Academic Press.)
- Published
- 1998
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16. IMPLICIT VS. LETTER-BY-LETTER READING IN PURE ALEXIA: A TALE OF TWO SYSTEMS.
- Author
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Saffran EM and Coslett HB
- Abstract
Recent studies of pure alexia present a contradictory picture. Despite evidence of impaired letter identification in letter-by-letter readers, some patients are able to carry out lexical decision and other tasks under conditions of rapid presentation, although they are seldom able to identify these stim uli explicitly. We review evidence for both facets of pure alexic performance and offer an accountof this pattern in terms ofright-and left-hemisphere reading mechanisms. Specifically, we suggest that the right hemisphere supports performance in covert reading tasks, and that letter-by-letter reading is the product of the left hemisphere, operating on information transmitted from the right.
- Published
- 1998
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17. The origins of formal paraphasias in aphasics' picture naming.
- Author
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Gagnon DA, Schwartz MF, Martin N, Dell GS, and Saffran EM
- Subjects
- Adult, Aged, Analysis of Variance, Female, Functional Laterality, Humans, Male, Middle Aged, Phonetics, Severity of Illness Index, Vocabulary, Aphasia, Wernicke physiopathology, Brain physiopathology
- Abstract
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.
- Published
- 1997
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18. Lexical access in aphasic and nonaphasic speakers.
- Author
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Dell GS, Schwartz MF, Martin N, Saffran EM, and Gagnon DA
- Subjects
- Adult, Aged, Aged, 80 and over, Brain Injuries psychology, Female, Humans, Male, Middle Aged, Models, Psychological, Semantics, Aphasia physiopathology, Aphasia psychology, Aphasia rehabilitation, Psycholinguistics, Speech-Language Pathology
- Abstract
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.
- Published
- 1997
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19. Intact perceptual priming in a patient with damage to the anterior inferior temporal lobes.
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Srinivas K, Breedin SD, Coslett HB, and Saffran EM
- Abstract
We conducted three experiments to examine whether the anterior portion of the inferior temporal (IT) lobe is involved in the processing of visual objects in humans. In monkeys, damage to this region results in severe deficits in perception and in memory for visual objects. Our study was designed to examine both these processes in a patient (DM) with bilateral damage to the anterior portion of the inferior temporal lobe. Neuropsychological examination revealed a significant semantic impairment and a mild deficit in the discrimination of familiar objects from nonobjects. Despite these difficulties, the results of several studies indicated that DM was able to form and retain descriptions of the structure of objects. Specifically, DM showed normal perceptual priming for familiar and novel objects on implicit memory tests, even when the objects were transformed in size and left-right orientation. These results suggest that the anterior IT is not'involved in (1) the storage of pre-existing structural descriptions of known objects, (2) the ability to create new structural descriptions for novel objects, and (3) the ability to compute descriptions that are invariant with respect to changes in size and reflection. Instead, the anterior IT appears to provide the interface between structural descriptions of objects and their meanings.
- Published
- 1997
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20. Recovery in deep dysphasia: evidence for a relation between auditory - verbal STM capacity and lexical errors in repetition.
- Author
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Martin N, Saffran EM, and Dell GS
- Subjects
- Adult, Humans, Male, Reaction Time, Semantics, Aphasia, Wernicke complications, Language Disorders complications, Language Disorders rehabilitation
- Abstract
This study investigates the changes in auditory-verbal short-term memory (AVSTM) and error patterns in repetition observed in a Wernicke's aphasic, NC, over a period of about 2 years following the onset of a left middle cerebral artery aneurysm. When first tested, NC demonstrated deep dysphasia, a disorder characterized by the production of semantic errors in repetition and a severe disability in repeating nonwords. At this stage, his AVSTM span, assessed in a pointing task, was less than one item. As NC recovered somewhat, his performance on AVSTM tasks improved (span increased to two items), and his pattern of error in word repetition changed (fewer semantic errors, more formal paraphasias and neologisms). Other features of his span performance after some recovery resembled patterns associated with STM-based repetition impairments (reduced recency effects and reduced word length effects). In a series of computer simulation and empirical studies, we show that NC's repetition performance can be accounted for by varying two parameters of an interactive activation model of repetition adapted from Dell and O'Seaghdha's (1991) model of production: decay rate and temporal interval. These results provide support for the view that AVSTM performance depends on storage capacities intrinsic to the language processing system. Such a model allows deep dysphasia and STM-based repetition disorders to be seen as quantitative variants of the same underlying disturbance.
- Published
- 1996
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21. Origins of paraphasias in deep dysphasia: testing the consequences of a decay impairment to an interactive spreading activation model of lexical retrieval.
- Author
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Martin N, Dell GS, Saffran EM, and Schwartz MF
- Subjects
- Acute Disease, Adult, Aphasia physiopathology, Humans, Intracranial Aneurysm physiopathology, Male, Phonetics, Semantics, Speech Disorders physiopathology, Aphasia etiology, Intracranial Aneurysm complications, Speech Disorders etiology, Vocabulary
- Abstract
This study investigates an account of atypical error patterns within the framework of an interactive spreading activation model. Martin and Saffran (1992) described a patient, NC, whose error pattern was unusual for the occurrence of higher rates of form-related than meaning-related word substitutions in naming and the production of semantic errors in repetition. They proposed that NC's error pattern could be accounted for by a pathologically rapid decay of primed nodes in the semantic-lexical-phonological network that shifts the probabilities of error outcome in lexical retrieval. In the present study, Martin and Saffran's account was tested and supported in a series of simulations that reproduce essential features of NC's lexical error pattern in naming and repetition. Also described here are the results of a longitudinal study of NC's naming and repetition, which revealed a shift in relative lexical error rates toward a qualitatively normal pattern. This change in error pattern was simulated by assuming that recovery reflects resolution of the rapid decay rate toward normal levels. The patient data and computational studies are discussed in terms of their significance for the understanding of aphasic impairments and their implications for models of lexical retrieval.
- Published
- 1994
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22. Impairment of sentence comprehension.
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Saffran EM and Schwartz MF
- Subjects
- Child, Humans, Language, Reference Values, Semantics, Aphasia psychology, Speech Perception
- Abstract
We examine two different forms of comprehension impairment, 'semantic dementia' and 'asyntactic comprehension', focusing on the assignment of thematic roles; the determination of who did it to whom. We show, first, that the loss of word meaning does not impede thematic assignment in semantic dementia, demonstrating that syntactic information, along with some knowledge of the verb, is sufficient for the assignment of thematic roles. Studies of normal subjects indicate, however, that this process is normally subject to semantic influences; asked to judge the plausibility of sentences, subjects respond faster when thematic assignment is semantically constrained. The sentence plausibility judgments of 'asyntactic' comprehenders (aphasics with diminished syntactic control over thematic assignment) show increased effects of these semantic constraints. We discuss these results in relation to current issues in sentence processing.
- Published
- 1994
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23. Disordered speech production in aphasic and normal speakers.
- Author
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Schwartz MF, Saffran EM, Bloch DE, and Dell GS
- Subjects
- Aphasia psychology, Concept Formation, Humans, Male, Middle Aged, Phonetics, Practice, Psychological, Regression Analysis, Semantics, Aphasia physiopathology, Models, Psychological, Speech physiology
- Abstract
Two empirical studies are presented which seek to extend the parallels between disordered speech production in aphasia and in normals. Study 1 compares the rate and distribution of some theoretically interesting error types in a jargon aphasic and a normal error corpus. Study 2 is an investigation of how the error pattern of normal speakers evolves as utterances become more practiced. On the basis of these studies, we offer a hypothesis about the nature of the variation between more and less disordered systems. Our claim, which is developed in the context of spreading activation models of production, is that such variation is tied to the ability of the system to deliver activation to intended units, relative to that of unintended units, within the time required by the task at hand.
- Published
- 1994
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24. Reading in pure alexia. The effect of strategy.
- Author
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Coslett HB, Saffran EM, Greenbaum S, and Schwartz H
- Subjects
- Cerebral Infarction complications, Humans, Language Tests, Male, Middle Aged, Semantics, Dyslexia, Acquired physiopathology, Reading
- Abstract
A number of investigators have demonstrated that patients with pure alexia comprehend briefly presented words which they are unable to explicitly identify. We suggested previously that these patients may read by means of two distinct procedures: a laborious letter-by-letter method and a 'whole-word' procedure which, at least initially, does not support explicit word identification. We report a test of this proposal in a patient with pure alexia. We reasoned that if the patient had access to two distinct and incompatible procedures, he might be induced to switch from one to the other by changing task demands. We found that when instructed to name words, the patient employed a letter-by-letter strategy; in contrast, when instructed to make lexical decision or semantic judgements about rapidly presented words, he appeared to use a 'whole-word' strategy. These data support the hypothesis that two distinct procedures are available to this patient. We argue, further, that is necessary to suppress use of the letter-by-letter strategy to demonstrate whole word reading capability in pure alexics, and that failure to do so may account for negative findings in other cases reported in the literature.
- Published
- 1993
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25. A computational account of deep dysphasia: evidence from a single case study.
- Author
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Martin N and Saffran EM
- Subjects
- Adult, Aphasia complications, Aphasia physiopathology, Brain physiopathology, Humans, Language Disorders etiology, Language Tests, Male, Memory Disorders etiology, Semantics, Speech Acoustics, Speech Discrimination Tests, Speech Production Measurement, Aphasia diagnosis, Language Disorders diagnosis, Memory Disorders diagnosis
- Abstract
We present a case study of a patient, NC, who demonstrates the defining characteristics of deep dysphasia including semantic errors in repetition and an inability to repeat nonwords. In addition, NC's single word repetition and lexical decision performances are influenced by the imageability of the word input. NC also demonstrates a severely restricted phonological short-term memory (one digit, one word). Although his phonological discrimination is good in a minimal pairs judgment task, it becomes impaired when a delay is imposed or rehearsal is prevented between presentation of each member of a pair. NC's output is fluent but contains many formal paraphasias and neologisms. NC's total language profile is evaluated within the framework of Dell's (1986) interactive spreading activation model of language production. Adapting this output model to input processes, we account for all of NC's deep dysphasic symptoms as well as his pattern of production in a way that is more parsimonious than other attempts to model this disorder. In particular, we suggest that the semantic and formal paraphasias in naming and repetition result from a pathological increase in the rate of decay of primed nodes in the semantic-lexical-phonological network. This rapid decay increases the probability that phonologically and/or semantically related lexical nodes primed by top-down and bottom-up feedback during the operation of lexical activation and retrieval will be activated and selected instead of the lexical target. The advantages of using this model to account for aphasic symptoms and the implications for other lexical theories are discussed.
- Published
- 1992
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26. Optic aphasia and the right hemisphere: a replication and extension.
- Author
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Coslett HB and Saffran EM
- Subjects
- Aged, Agnosia diagnosis, Agnosia physiopathology, Anomia diagnosis, Anomia physiopathology, Aphasia physiopathology, Aphasia psychology, Brain physiopathology, Cerebrovascular Disorders diagnosis, Cerebrovascular Disorders physiopathology, Humans, Male, Neuropsychological Tests, Aphasia diagnosis, Functional Laterality physiology, Language Tests, Semantics, Visual Perception physiology
- Abstract
Optic aphasia is a rare, visual modality-specific naming disorder. We describe a patient who developed this disorder subsequent to a left occipital lobe infarction. Like another case that we described previously, this patient performed normally on a variety of tasks assessing the recognition of objects he could not name. Additionally, although he never read aloud a single word, his performance on lexical decision and word comprehension tasks was far better than chance. We suggest that his performance was mediated by a right hemisphere semantic system.
- Published
- 1992
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27. Repetition and verbal STM in transcortical sensory aphasia: a case study.
- Author
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Martin N and Saffran EM
- Subjects
- Aged, Anomia diagnosis, Aphasia, Wernicke physiopathology, Cerebral Infarction complications, Dominance, Cerebral physiology, Female, Follow-Up Studies, Humans, Memory, Short-Term physiology, Pattern Recognition, Visual physiology, Phonetics, Retention, Psychology physiology, Semantics, Aphasia, Wernicke diagnosis, Cerebral Cortex physiopathology, Neuropsychological Tests, Verbal Behavior physiology
- Abstract
The repetition performance of a patient (S.T.) with transcortical sensory aphasia is examined in four experiments with particular emphasis on the STM capacities underlying her performance. S.T.'s repetition of word strings exceeding her span (two words) is characterized by good recall of the final items and a strong tendency to lose the initial items in the input string. This pattern contrasts with the serial position effects observed in a phonologically based STM impairment, and it is suggested that a lexical-semantic impairment, also evident in S.T.'s naming and lexical comprehension, contributes to her inability to retain the primacy portions of the input string. Lexical effects obtained in her reproduction of words and nonwords, as well as word strings (Experiments 1 and 2), indicate that under conditions of impaired semantics S.T. is relying on lexical phonological information to repeat. Priming by repeated exposure (Experiment 3) failed to improve her repetition performance, indicating that access to lexical information is brief and dependent on recent phonological input. In Experiment 4, the role of syntactic structure in S.T.'s sentence repetition was examined, and it was shown that syntactic structure affects the recall of order information, but not the number of items recalled. The repetition and verbal STM abilities of this patient, in light of her total language profile, are then evaluated in the context of a language-based view of verbal STM.
- Published
- 1990
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28. Agnosic behavior in anomia: a case of pathological verbal dominance.
- Author
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Marin OS and Saffran EM
- Subjects
- Agnosia etiology, Auditory Perception, Humans, Intelligence Tests, Male, Middle Aged, Psychological Tests, Visual Perception, Agnosia diagnosis, Aphasia complications, Dominance, Cerebral, Verbal Behavior
- Abstract
The interrelation of perceptual and verbral process was explored in a fluent aphasic with a naming disorder. This patient performed extremely well on complex perceptual tasks as long as he was instructed to remain silent or to count aloud. Whe he began to talk about what he was doing, he misnamed many test items and behaved as if they were what he had called them. The verbal interference effect is explained in terms of cerebral dominance and interhemispheric interaction and it is suggested that a similar mechanism may apply in classical cases of agnosia.
- Published
- 1975
- Full Text
- View/download PDF
29. An analysis of speech perception in word deafness.
- Author
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Saffran EM, Marin OS, and Yeni-Komshian GH
- Subjects
- Adult, Discrimination, Psychological, Humans, Information Theory, Male, Phonetics, Aphasia diagnosis, Auditory Perception, Dominance, Cerebral, Speech
- Published
- 1976
- Full Text
- View/download PDF
30. Dissociations of language function in dementia: a case study.
- Author
-
Schwartz MF, Marin OS, and Saffran EM
- Subjects
- Aphasia psychology, Discrimination Learning, Dissociative Disorders psychology, Female, Humans, Mental Recall, Middle Aged, Pattern Recognition, Visual, Semantics, Speech Perception, Verbal Learning, Dementia psychology, Language Disorders psychology
- Published
- 1979
- Full Text
- View/download PDF
31. The quantitative analysis of agrammatic production: procedure and data.
- Author
-
Saffran EM, Berndt RS, and Schwartz MF
- Subjects
- Adult, Aged, Articulation Disorders diagnosis, Cerebral Infarction complications, Female, Humans, Male, Middle Aged, Neuropsychological Tests, Semantics, Aphasia diagnosis, Aphasia, Broca diagnosis, Speech Production Measurement
- Abstract
Despite the long-standing interest in structural aspects of aphasic production, no method has emerged for the systematic analysis of aphasic speech. This paper attempts to address that need by outlining a procedure for the quantitative assessment of narrative speech which yields measures for both morphological and structural characteristics of aphasic production. In addition to complete instructions for carrying out this analysis, data for three groups of subjects are presented: agrammatic aphasics, aphasics who are similarly nonfluent but not clinically judged as agrammatic, and normal controls. While the agrammatics were distinguishable from the nonagrammatic patients on most measures, both nonfluent groups showed comparable reductions in the structural complexity of their propositional utterances. Other findings include indications from individual patient data that aspects of grammatical morphology may dissociate in agrammatism.
- Published
- 1989
- Full Text
- View/download PDF
32. Localization and characterization of transport-related elements in the plasma membrane of turtle bladder epithelial cells.
- Author
-
Brodsky WA, Cabantchik ZI, Davidson N, Ehrenspeck G, Kinne-Saffran EM, and Kinne R
- Subjects
- 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid pharmacology, Adenylyl Cyclases metabolism, Animals, Epithelium metabolism, Magnesium metabolism, Ouabain pharmacology, Potassium metabolism, Protein Kinases metabolism, Sodium metabolism, Sodium-Potassium-Exchanging ATPase metabolism, Turtles, Biological Transport, Active drug effects, Cell Membrane metabolism, Urinary Bladder metabolism
- Abstract
A mixed membrane preparation obtained from turtle bladder epithelial cells contains (Na+ + K+)-ATPase, adenylate cyclase and protein kinase, which interact with ouabain, norepinephrine and cyclic AMP, respectively. When such a preparation is obtained from bladders which had been preexposed to serosal fluids containing the tritiated form of 4,4'-diisothiocyano-2,2'-disulfonic stilbene, the subsequently isolated membrane proteins are enriched in tritium as well as in the afore-mentioned enzymes, none of which is inhibited. Free-flow electrophoresis separates the mixed membrane preparation into two distinguishable groups: one, construed as apical membranes, is enriched in norepinephrine-sensitive adenylate cyclase and cyclic AMP-sensitive protein kinase; the other, construed as basal-lateral membranes, is enriched in ouabain-sensitive ATPase and 4,4'-diisothiocyano-2,2'-disulfonic stilbene-binding proteins. The physiological counterparts of these enzymatically defined membrane markers are the mucosal sidedness of the transport effects of norepinephrine and cyclic AMP derivatives and the serosal sidedness of the transport effects of ouabain and disulfonic stilbenes in the intact turtle bladder. The discreteness and ion selectivity of each membrane-bound, transport-related element are discussed in relation to the corresponding characteristics of each transport process in vivo; the possibility of regulation of anion transport by adenylate cyclase-protein kinase system is also discussed.
- Published
- 1979
- Full Text
- View/download PDF
33. The word order problem in agrammatism. I. Comprehension.
- Author
-
Schwartz MF, Saffran EM, and Marin OS
- Subjects
- Adult, Humans, Language Tests, Psycholinguistics, Semantics, Aphasia psychology, Aphasia, Broca psychology
- Published
- 1980
- Full Text
- View/download PDF
34. Reading without phonology: evidence from aphasia.
- Author
-
Saffran EM and Marin OS
- Subjects
- Dyslexia, Acquired psychology, Female, Humans, Middle Aged, Visual Perception, Aphasia psychology, Phonetics, Reading
- Published
- 1977
- Full Text
- View/download PDF
35. The word order problem in agrammatism. II. Production.
- Author
-
Saffran EM, Schwartz MF, and Marin OS
- Subjects
- Adult, Humans, Language Tests, Psycholinguistics, Semantics, Aphasia psychology, Aphasia, Broca psychology
- Published
- 1980
- Full Text
- View/download PDF
36. Semantic mechanisms in paralexia.
- Author
-
Saffran EM, Schwartz MF, and Marin OS
- Subjects
- Aphasia complications, Association, Humans, Names, Dyslexia therapy, Semantics
- Published
- 1976
- Full Text
- View/download PDF
37. Evidence for preserved reading in 'pure alexia'.
- Author
-
Coslett HB and Saffran EM
- Subjects
- Adult, Aged, Aged, 80 and over, Cerebral Infarction complications, Cerebral Infarction psychology, Dyslexia, Acquired etiology, Female, Humans, Language Tests, Male, Middle Aged, Thinking, Dyslexia, Acquired psychology, Reading
- Abstract
We describe 4 patients who developed pure alexia after infarctions of the left cerebral hemisphere. All subjects employed a letter-by-letter strategy (with varying degrees of success) to explicitly identify visually presented words. Although all 4 subjects explicitly denied that they could identify briefly presented words, they all performed significantly better than chance on lexical decision and forced-choice semantic categorization tasks with briefly presented words which they could not explicitly identify. Three subjects regained the ability to explicitly identify briefly presented words; these subjects were more accurate with nouns than functors and words of high as compared with low imageability. Additionally, these subjects were impaired in the processing of suffixes. These data are not accommodated by the 'disconnection' account of pure alexia but are more consistent with the hypothesis that reading in these patients is mediated by the right hemisphere.
- Published
- 1989
- Full Text
- View/download PDF
38. [Nature of repetition disorders in conduction aphasia].
- Author
-
Marin OS, Saffran EM, and Schwartz MF
- Subjects
- Adolescent, Aged, Dominance, Cerebral, Female, Humans, Language Disorders complications, Male, Memory Disorders complications, Memory, Short-Term physiology, Neuropsychological Tests, Aphasia diagnosis
- Abstract
The skeptic over the existence of this important clinical entity, are now very few. Anatomo-clinical studies and the analysis of altered cognitive procedures suggest, however, that we are dealing with a heterogeneous group. Two models of conduction apahasias are presented, in which the mechanism of the altered repetition, as well as the probable localization of the lesion, differ considerably. One has a lesion in the posterior parietal region of the left hemisphere and it exemplifies an acoustic verbal memory deficit (short term memory). The other points at a functional disconnection between the decodification and verbal processes and those of expression. In this case, we are dealing with a left temporal lesion in a left-handed individual. The analysis of our material and of the clinical literature upholds the idea of a plurality of the altered mechanisms in the verbal repetition and suggest that the conduction aphasia is a syndrome.
- Published
- 1977
39. Dissociations of language in aphasia: implications for normal function.
- Author
-
Marin OS, Saffran EM, and Schwartz MF
- Subjects
- Auditory Perception, Cognition, Humans, Memory, Short-Term, Reading, Speech Disorders physiopathology, Vocabulary, Aphasia physiopathology, Psycholinguistics methods
- Published
- 1976
- Full Text
- View/download PDF
40. Immediate memory for word lists and sentences in a patient with deficient auditory short-term memory.
- Author
-
Saffran EM and Marin OS
- Subjects
- Humans, Male, Semantics, Speech, Time Factors, Visual Perception, Aphasia, Auditory Perception, Language, Memory, Short-Term, Verbal Behavior
- Published
- 1975
- Full Text
- View/download PDF
41. Preserved object recognition and reading comprehension in optic aphasia.
- Author
-
Coslett HB and Saffran EM
- Subjects
- Aged, Aphasia diagnostic imaging, Humans, Language Tests, Male, Neuropsychological Tests, Tomography, X-Ray Computed, Aphasia psychology, Form Perception, Pattern Recognition, Visual, Reading
- Abstract
Optic aphasia is characterized by the ability to name from description and palpation but an inability to name visually-presented objects. Although originally attributed to a disconnection of visual information from object names, optic aphasia is often considered to be a mild form of visual agnosia. We describe a patient with optic aphasia who could access semantic information relevant to objects he could not name and comprehend written words he could not read. These data suggest that, at least in certain cases, this visual modality-specific naming impairment may not be attributable to impaired visual recognition. We suggest that this patient's preserved object recognition and reading comprehension was mediated by a semantic system supported by the right hemisphere.
- Published
- 1989
- Full Text
- View/download PDF
42. Reading in deep dyslexia is not ideographic.
- Author
-
Saffran EM
- Subjects
- Adolescent, Adult, Cerebral Cortex physiopathology, Discrimination Learning physiology, Dyslexia, Acquired physiopathology, Female, Humans, Male, Middle Aged, Orientation physiology, Phonetics, Dyslexia, Acquired psychology, Reading
- Published
- 1980
- Full Text
- View/download PDF
43. Neuropsychological approaches to the study of language.
- Author
-
Saffran EM
- Subjects
- Aphasia diagnosis, Humans, Memory, Short-Term, Phonetics, Psycholinguistics, Semantics, Speech Perception, Speech Production Measurement, Vocabulary, Aphasia psychology
- Abstract
This paper discusses recent studies of aphasia from the perspective of theories of normal language structure and processing. Patterns of language breakdown are considered to reflect the componential structure of the language system. In some cases, brain damage is seen to fractionate language along lines suggested by existing psycholinguistic models: certain syndromes can be viewed as more or less isolated disturbances involving lexical, syntactic or phonological components of the language system, or psychological functions such as short-term memory. In other cases, aphasic deficits point to levels of language function not yet well specified by normative models. This review of psycholinguistically oriented research on aphasia supports the effort to construct integrated theories of language functioning on the basis of both normal and pathological performances.
- Published
- 1982
- Full Text
- View/download PDF
44. Sensitivity to grammatical structure in so-called agrammatic aphasics.
- Author
-
Linebarger MC, Schwartz MF, and Saffran EM
- Subjects
- Adult, Female, Humans, Judgment, Middle Aged, Psychological Theory, Semantics, Vocabulary, Aphasia psychology, Aphasia, Broca psychology, Linguistics
- Published
- 1983
- Full Text
- View/download PDF
45. Properties of a synthetic plasma membrane marker: fluorescent-mercury-dextran.
- Author
-
Simon B, Zimmerschied G, Kinne-Saffran EM, and Kinne R
- Subjects
- Adenosine Triphosphatases analysis, Alkaline Phosphatase analysis, Animals, Binding Sites, Centrifugation, Density Gradient, Chloromercuribenzoates, Drug Stability, Electrophoresis, Evaluation Studies as Topic, Fluoresceins, Kidney cytology, Kinetics, Mercury, Methods, Molecular Weight, Protein Binding, Rats, Spectrophotometry, Ultraviolet, Ultracentrifugation, Cell Membrane enzymology, Dextrans, Kidney enzymology
- Published
- 1973
- Full Text
- View/download PDF
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