Cases reported "Prosopagnosia"

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1/13. Naming people ignoring semantics in a patient with left frontal damage.

    Studies about proper name anomia generally assume that persons' names are harder to recall than other semantic information one knows about them and that name retrieval is not possible without biographical knowledge. We describe a patient, SB, who, after a left frontal haemorrhage, was unable to recall any biographical information about people she could name. Moreover, she had a normal score in an Object Picture Naming Test, but gave confabulatory answers in a Semantic Questionnaire involving the same items. The role of frontal function in producing this pattern of impairment is discussed, together with the possible existence of a direct route from visual perception to proper name retrieval.
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2/13. Effect of training frequency on face-name recall by adults with traumatic brain injury.

    Many TBI survivors have difficulty recalling the names of people with whom they frequently interact. Researchers have established that mnemonics and visual imagery strategies are often effective in facilitating encoding and recall of such information; however, no research exists pertaining to the frequency that such training should occur. The purpose of this study was to assess the relative effectiveness of three frequencies of intervention sessions--once per day, two times per week, and five times per day--on TBI survivors' ability to recall face-name associations. Results showed that sessions held daily and twice a week were more effective than sessions held five times per day. Mnemonics and visual imagery strategies were effective for four of the seven participants, regardless of frequency of intervention sessions. Implications for treatment and future research are discussed.
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3/13. Severe developmental prosopagnosia in a child with superior intellect.

    Developmental prosopagnosia, a lifelong inability to learn and recognize familiar faces, has rarely been reported, and there are even fewer cases that have been studied during childhood. Of the cases studied during childhood, significant "apperceptive" features to the face recognition defect have been noted. We had an opportunity to conduct extensive standard and experimental neuropsychological, psychophysiological, and neuroanatomical studies in a five-year-old child with severe developmental prosopagnosia. The subject was intellectually gifted (FSIQ = 130), but had a marked discrepancy between verbal and nonverbal abilities (VIQ = 140, PIQ = 110). Although some visual perceptual weaknesses were apparent, the subject's face recognition defect was found to cnform most closely to the "associative" type, and he did not have visual recognition deficits for any categories of nonunique entities. A novel finding was that the child's covert recognition of familiar faces based on an autonomic index was normal, suggesting that as in some adult-onset cases, the brain is capable of acquiring some information about familiar faces, even without conscious recognition. The child also had normal judgments of facial emotional expressions. Our report extends the understanding of the neuropsychological features of developmental prosopagnosia, and may help narrow the search for neuroanatomical correlates of this condition, which have yet to be identified.
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4/13. prosopagnosia as a deficit in encoding curved surface.

    RP is a case of "developmental" prosopagnosia who, according to brain-imaging segmentation data, shows reduction in volume of a limited set of structures of the right hemisphere. RP is as accurate as control subjects in tasks requiring the perception of nonface objects (e.g., matching subordinate labels to exemplars, naming two-tone images), with the exception of one perceptual task: The matching of different perspectives of amoebae-like stimuli (i.e., volumes made of a single smooth surface). In terms of speed ("efficiency") of responses, RP's performance falls clearly outside the normal limits also in other tasks that include "natural" but nonface stimuli (i.e., animals, artia facts). Specifically, RP is slow in perceptual judgments made at very low (subordinate) levels of semantic categorization and for objects and artifacts whose geometry present much curved features and surface information. We conclude from these analyses that prosopagnosia can be the result of a deficit in the representation of basic geometric volumes made of curved surface. In turn, this points to the importance (necessity) for the normal visual system of such curved and volumetric information in the identification of human faces.
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5/13. Selective sparing of face learning in a global amnesic patient.

    OBJECTIVE: To test the hypothesis that visual memory for faces can be dissociated from visual memory for topographical material. METHOD: A patient who developed a global amnesic syndrome after acute carbon monoxide poisoning is described. A neuroradiological examination documented severe bilateral atrophy of the hippocampi. RESULTS: Despite a severe anterograde memory disorder involving verbal information, abstract figures, concrete objects, topographical scenes, and spatial information, the patient was still able to learn previously unknown human faces at a normal (and, in some cases, at a higher) rate. CONCLUSIONS: Together with previous neuropsychological evidence documenting selective sparing of topographical learning in otherwise amnesic patients, this case is indicative of the fact that the neural circuits involved in face recognition are distinct from those involved in the recognition of other visuoperceptual material (for example, topographical scenes).
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6/13. prosopagnosia: a case study involving problems in processing configural information.

    An ongoing issue in face recognition research is whether holistic face processing relies on the segregation of local discrete facial parts. Evidence in favor of the holistic-plus-parts view stems from a recent study reported by Arguin and Saumier (1999), who show that the priming effects of individual facial parts (i.e., eyes, nose, mouth, orcontour) depends on the presence of configural information and that the magnitude of priming augments as the number of facial parts serving as primes increase. The present study demonstrates that these global processing effects are absent in a prosopagnosic patient (A.R.), who shows no priming from single face parts and a linear increase in the magnitude of priming as a function of the number of parts presented. These findings indicate that A.R. is incapable of integrating individual facial parts into a global facial configuration ant that this is likely at the root of her prosopagnosia.
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7/13. face context interferes with local part processing in a prosopagnosic patient.

    We investigated the role of local and global information on perceptual encoding of faces in patient HJA, who shows prosopagnosia and visual agnosia following occipito-temporal damage. HJA and an age-matched control were tested in a simultaneous matching task which focused on detection of local changes in faces: the inversion of central parts (eyes and mouth) relative to their context (as in the Thatcher illusion). Same-different judgements were made to normal, "that cherised" and mixed type face pairs. Whole faces (Experiment 1), or face parts (Experiment 2), were presented in upright and inverted orientations. Compared to the control, HJA was severely impaired at matching whole faces, but he improved dramatically when face parts were presented in isolation. This suggests an inhibitory influence of face context on HJAs processing of local parts and a relatively intact ability to process part-based information from a face (when context cannot interfere). face inversion did not affect HJAs performance. A control experiment (Experiment 3) with non-face stimuli (houses) suggested that the inhibitory influence of context on HJAs performance was restricted to faces. These results indicate that contextual information in a face can have an adverse influence on the processing of local part-based information in prosopagnosia.
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8/13. Slowly progressive defect in recognition of familiar people in a patient with right anterior temporal atrophy.

    We report the case of a patient (C.O.) who showed a selective defect in the recognition of familiar people, with very mild disease progression during a period of 30 months resulting from focal atrophy of the right temporal lobe. On formal neuropsychological testing, C.O. obtained high scores on tests of general intelligence, episodic memory, language, executive functions, selective attention, visual recognition and visual-spatial abilities. On more specific tasks of familiar and unfamiliar face recognition, C.O. scored above the controls' means on perceptual tests, but obtained highly pathological results on amnesic-associative tests. His disorder of recognition of familiar people was not due to loss of person-specific information, since he obtained highly abnormal naming scores when presented with photographs of famous people but borderline or mildly abnormal scores in a tasks in which he had to name celebrities from verbal definitions. On the other hand, C.O.'s recognition disorder could not be considered to be a form of 'associative prosopagnosia' since a similar defect was observed when he was requested to access information about famous persons through their voice rather than their face. Two alternative interpretations are advanced to explain C.O.'s inability to access his relatively spared person-specific knowledge not only through the person's face but also through the person's voice. The first hypothesis is that, before accessing the person-specific information, unimodal recognition channels must converge into a multimodal, non-verbal person-recognition system and that the right anterior temporal cortices play a crucial role in this integrative activity. The second hypothesis is that the face-recognition units have privileged access to person-specific semantic knowledge and that other recognition subsystems require coactivation of the face-recognition units in order to access person-specific semantic information.
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9/13. Covert person recognition: its fadeout in a case of temporal lobe degeneration.

    Covert person recognition was investigated longitudinally over a three-year period in a patient suffering from "Crossmodal Familiar Person Agnosia", possibly due to a fronto-temporal dementia in its right temporal variant (Gentileschi et al., 2001). The progressive neuronal degeneration in the cortical regions critical for face recognition (viz., right infero-temporal areas) presented us with the opportunity to check Burton et al.'s (1991) and Farah et al.'s (1993) hypothesis on the dissociation between overt and covert face recognition in a neuropsychological condition which, however, is neurologically and cognitively different from that of focal "associative prosopagnosia". Covert person recognition starting from overtly unrecognised faces was assessed by means of learning tasks of face/name association involving celebrities. It was assumed that some unconsciously spared information would selectively enhance the relearning rates when famous faces were paired with their true names. In fact, the true-name advantage (i.e., selective saving for experimental relearning of true name pairings) reached significance at first assessment, carried out five years from clinical onset. Effect faded away two and three years later on, thus abolishing the overt/covert dissociation in face recognition. These findings support Burton et al.'s (1991) and Farah et al.'s (1993) hypothesis of covert face recognition as the consequence of partial and incomplete activation of person semantics, due, in the present case, to the impoverishment of Gentileschi et al.'s (2001) "exemplar semantics" storehouse. Moreover, it turned out that covert recognition does not imply a different learning slope, but an overall different level of the learning profile.
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10/13. Exploring the role of motion in prosopagnosia: recognizing, learning and matching faces.

    HJA has been completely unable to recognize faces since suffering a stroke some 22 years ago. Previous research has shown that he is poor at judging expressions from static photographs of faces, but performs relatively normally at these judgements when presented with moving point-light patterns (Humphreys et al., 1993). Recent research with non-prosopagnosic participants has suggested a beneficial role for facial motion when recognizing familiar faces and learning new faces. Three experiments are reported that investigate the role of face motion for HJA when recognizing (Experiment 1), learning (Experiment 2) and matching faces (Experiment 3). The results indicate that HJA is unable to use face motion to explicitly recognize faces and is no better at learning names for moving faces than static ones. However, HJA is significantly better at matching moving faces for identity, an opposite pattern to that found with age-matched and undergraduate control participants. We suggest that HJA is not impaired at processing motion information but remains unable to use motion as a cue to identity.
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