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ABSTRACT: The purpose of the present study was to assess the relationship between brain metabolism and empathic response. Six right-handed healthy volunteers were scanned with PET and fluorodeoxyglucose twice: during an interview about neutral story themes and during an empathic response eliciting interview about a story of a character in distress. Metabolic values in the medial and superior frontal gyrus, occipitotemporal cortices, thalamus and the cerebellum were higher during empathic response than during the neutral theme interview. Furthermore, the subjects' empathy scores were positively correlated with metabolism in the medial aspects of the superior frontal gyrus. Our results suggest that empathy consists of both affective and cognitive components and hence may involve cortices that mediate simulation of emotional processing and mental state attribution.
NeuroImage 09/2005; 27(2):468-72. · 5.89 Impact Factor
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ABSTRACT: The authors explored the neurobiology of sarcasm and the cognitive processes underlying it by examining the performance of participants with focal lesions on tasks that required understanding of sarcasm and social cognition. Participants with prefrontal damage (n=25) showed impaired performance on the sarcasm task, whereas participants with posterior damage (n=16) and healthy controls (n=17) performed the same task without difficulty. Within the prefrontal group, right ventromedial lesions were associated with the most profound deficit in comprehending sarcasm. In addition, although the prefrontal damage was associated with deficits in theory of mind and right hemisphere damage was associated with deficits in identifying emotions, these 2 abilities were related to the ability to understand sarcasm. This suggests that the right frontal lobe mediates understanding of sarcasm by integrating affective processing with perspective taking.
Neuropsychology 06/2005; 19(3):288-300. · 3.82 Impact Factor
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ABSTRACT: To examine the hypothesis that patients with ventromedial (VM) frontal lesions are impaired in the affective rather than cognitive facets of theory of mind (ToM).
Prefrontal brain damage may result in impaired social behavior, especially when the damage involves the orbitofrontal/VM prefrontal cortex (PFC). It has been previously suggested that deficits in ToM may account for such aberrant behavior. However, inconsistent results have been reported, and different regions within the frontal cortex have been associated with ToM impairment.
The performance of 26 patients with localized lesions in the PFC was compared with responses of 13 patients with posterior lesions and 13 normal control subjects. Three ToM tasks differing in the level of emotional processing involved were used: second-order false belief task, understanding ironic utterances, and identifying social faux pas.
The results indicated that patients with VM (but not dorsolateral) prefrontal lesions were significantly impaired in irony and faux pas but not in second-order false belief as compared with patients with posterior lesions and normal control subjects. Lesions in the right VM area were associated with the most severe ToM deficit. These results are discussed in terms of the cognitive and affective facets of "mind-reading" processes mediated by the VM cortex.
Cognitive and Behavioral Neurology 04/2005; 18(1):55-67. · 1.34 Impact Factor
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ABSTRACT: The present study was designed to examine the degree of impairment in cognitive and affective empathy among patients with focal brain lesions, and the contribution of specific cognitive abilities (such as cognitive flexibility and processing of emotional information), to empathy. The cognitive and affective empathic response of patients with localized prefrontal lesions (n=36) was compared to responses of patients with parietal lesions (n=15) and healthy control subjects (n=19). Results indicate that patients with prefrontal lesions (especially those with lesions involving the orbitoprefrontal and medial regions) were significantly impaired in both cognitive and affective empathy as compared to parietal patients and healthy controls. When the damage was restricted to the prefrontal cortex, either left- or right-hemisphere lesions resulted in impaired empathy. However, when the lesion involved the right hemisphere, patients with parietal lesions were also impaired. The pattern of relationships between cognitive performance and empathy suggested dissociation between the cognitive correlates of affective and cognitive empathy.
Journal of Clinical and Experimental Neuropsychology 12/2004; 26(8):1113-27. · 2.13 Impact Factor
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ABSTRACT: Although changes in novelty seeking and harm avoidance have been reported among patients with Parkinson's disease (PD), the findings regarding the neurochemical correlates of such changes are inconsistent. This study was designed to examine the hypothesis that different patterns of motor and neurochemical asymmetry in PD may have contributed to the conflicting results.
Forty PD patients (divided into two groups according to initial asymmetry in dopamine deficit: left hemisphere, n = 22; right hemisphere, n = 18) and 17 age matched healthy controls completed the Tridimensional Personality Questionnaire (Cloninger, 1987).
Only patients with greater dopamine loss in the left hemisphere showed reduced novelty seeking, whereas only patients with reduced dopamine in the right hemisphere reported higher harm avoidance than matched healthy controls. Novelty seeking was not associated with disease duration, current motor symptoms, or medication, whereas harm avoidance was significantly correlated only with the severity of bradykinesia and depression.
Approach and avoidance reflect different patterns of dopaminergic asymmetry. Whereas reduced novelty seeking reflects deficit in the mesolimbic branch of ascending dopamine transmission in the left hemisphere, increased harm avoidance is associated with greater dopamine loss in the right striatum.
Journal of Neurology Neurosurgery & Psychiatry 08/2004; 75(7):972-5. · 4.76 Impact Factor
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ABSTRACT: Cognition and the effects of carotid endarterectomy (CEA) were evaluated in 22 non-demented subjects with vascular risk factors (VRF) and asymptomatic severe carotid artery stenosis (ASCAS), 14 volunteers with VRF but without stenosis, and 24 healthy controls (HC) without VRF. Non-demented subjects with VRF, with or without carotid stenosis scored inferior to HC. It is concluded that carotid stenosis is not a primary cause of cognitive deterioration and CEA does not improve cognition in patients with ASCAS.
European Journal of Neurology 10/2003; 10(5):525-8. · 3.69 Impact Factor
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ABSTRACT: Impaired empathic response has been described in patients following brain injury, suggesting that empathy may be a fundamental aspect of the social behavior disturbed by brain damage. However, the neuroanatomical basis of impaired empathy has not been studied in detail. The empathic response of patients with localized lesions in the prefrontal cortex (n = 25) was compared to responses of patients with posterior (n = 17) and healthy control subjects (n = 19). To examine the cognitive processes that underlie the empathic ability, the relationships between empathy scores and the performance on tasks that assess processes of cognitive flexibility, affect recognition, and theory of mind (TOM) were also examined. Patients with prefrontal lesions, particularly when their damage included the ventromedial prefrontal cortex, were significantly impaired in empathy as compared to patients with posterior lesions and healthy controls. However, among patients with posterior lesions, those with damage to the right hemisphere were impaired, whereas those with left posterior lesions displayed empathy levels similar to healthy controls. Seven of nine patients with the most profound empathy deficit had a right ventromedial lesion. A differential pattern regarding the relationships between empathy and cognitive performance was also found: Whereas among patients with dorsolateral prefrontal damage empathy was related to cognitive flexibility but not to TOM and affect recognition, empathy scores in patients with ventromedial lesions were related to TOM but not to cognitive flexibility. Our findings suggest that prefrontal structures play an important part in a network mediating the empathic response and specifically that the right ventromedial cortex has a unique role in integrating cognition and affect to produce the empathic response.
Journal of Cognitive Neuroscience 05/2003; 15(3):324-37. · 5.18 Impact Factor
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ABSTRACT: Although lack of empathy has been considered a central characteristic of Asperger syndrome, quantitative and qualitative assessments of empathy in this syndrome are lacking. We present two cases of adolescents with Asperger syndrome who show extreme deficits on measures of both cognitive and affective empathy. Analysis of their performance on tasks assessing cognitive and affective processing did not reveal significant impairment in executive functions, nor in their ability to recognize emotions or the ability to create a mental representation of another person's knowledge. However, both patients were unable to integrate the emotional content with mental representations and deduce the other person's emotional state. These results suggest that impaired empathy in individuals with Asperger syndrome may be due to impaired integration of the cognitive and affective facets of the other person's mental state.
Neurocase 02/2002; 8(3):245-52. · 1.11 Impact Factor
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ABSTRACT: Hebrew language versions of phonemic and semantic fluency were administered to samples of normal control participants and individuals who had been hospitalized for 24 hr following a head injury. For the control sample, verbal fluency tasks were normally distributed and significantly correlated with education. The head injury sample's word generation was significantly lesser than that of the control's and not at all related to educational attainment. The findings provide evidence for the use of Hebrew fluency measures for clinical assessment and the need for collection of normative data across education levels.
Applied Neuropsychology 02/2001; 8(4):248-50. · 1.17 Impact Factor
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ABSTRACT: The Hebrew language version of the Trail Making Test (TMT; Army Individual Test Battery, 1944) was administered to a group of normal control participants as well as a sample of outpatients approximately 1 year following a head injury. A ratio of TMT-B to TMT-A performance was computed in an effort to establish usable cutting scores for the Hebrew TMT. A ratio of 2.26 was observed to result in 63% sensitivity and 77% specificity for the sample, with positive predictive power of 71% and negative predictive power of 70%. A more stringent cutoff of 3.09 reduced sensitivity (22%) and negative predictive power (44%). In contrast, specificity (97%) and positive predictive power (86%) were greatly improved once the speed of TMT-A performance was also considered. The more conservative cutoff is considered appropriate when a finding is indicative of pathological performance.
Applied Neuropsychology 02/2000; 7(3):186-8. · 1.17 Impact Factor
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ABSTRACT: The assessment of neurobehavioural outcome after head injury in older patients (> 60 year old) has met with difficultives, due to the obstacles in finding subjects who would constitute an appropriate control group. In the present study, survivors of closed head injury (CHI) of this age group were compared to two control groups: (1) orthopaedic patients (OP) who were injured in similar circumstances but did not sustain head injury and (2) healthy, age-matched volunteers (HC). Compared with HC, CHI and OP were impaired on word fluency, memory and reasoning. No differences were found between CHI and the OP. These results may indicate that, rather than resulting only from the head injury brought about by falling, the cognitive decline may predate the injury and increase the risk of accidents in old age.
Brain Injury 12/1997; 11(12):871-5. · 1.36 Impact Factor
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Brain and Cognition 48(2-3):558-63. · 3.17 Impact Factor
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ABSTRACT: Behavioral abnormalities account for much of the morbidity of vascular dementia (VaD) and Alzheimer's disease (AD). The goals of the study were to compare the behavioral changes in patients with VaD associated with ischemic white matter subcortical changes and lacunar infarctions (VaD-WSI) to those in patients with AD.
Thirty outpatients with VaD and multiple lacunar infarctions in the periventricular white matter and 30 AD patients, matched for age and severity of dementia, were enrolled in this prospective study. The behavioral abnormalities of these patients were assessed by interviewing their caregivers with the Neuropsychiatric Inventory.
A similar spectrum of noncognitive behavioral changes was found in AD and WSI patients. In VaD-WSI, the severity of delusions, hallucinations, aggression, irritability, aberrant motor behavior, nighttime behavior and appetite changes was correlated with cognitive decline, whereas depression, apathy, anxiety and euphoria were unrelated to the severity of dementia. In AD, none of the behavioral changes correlated with the severity of dementia.
Behavioral changes are frequent in VaD-WSI and are present regardless of the severity of the cognitive decline. It is therefore important to assess behavioral as well as cognitive changes at early stages of the illness, to ensure appropriate treatment.
Dementia and Geriatric Cognitive Disorders 11(5):294-8. · 2.14 Impact Factor
