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V Parlato

Publications and source records attributed to V Parlato.

8 recordsLinked to original sources
PubMed1998

Cortical networks implicated in semantic and episodic memory: common or unique?

While previous functional neuroimaging studies have shown that semantic and episodic memory tasks activate different cortical regions, they never compared regional cerebral blood flow (rCBF) patterns associated with semantic and episodic memory within the same experimental design. In this study, we used H2(15)O PET to study subjects in the course of semantic and episodic memory tasks. rCBF was measured in 9 normal volunteers during a resting baseline condition and two cognitive tasks. In the semantic categorisation task subjects heard a list of concrete words and had to respond to words belonging to the "animals" or "food" category. In the episodic recognition task subjects heard a list of concrete words, half "old", i.e. belonging to the list of the semantic categorisation task, and half "new", i.e. presented for the first time. Subjects had to respond to the "old" words. Both tasks were compared to a resting condition. Statistical analysis was performed with Statistical Parametric Mapping (SPM). Compared to the resting condition, the semantic tasks, activated the superior temporal gyri bilaterally, the left frontal cortex, and right premotor cortex. The episodic tasks activated the left superior temporal gyrus, the frontal cortex bilaterally, and the right inferior parietal cortex. Compared to the episodic memory tasks, the semantic memory tasks activated the superior temporal/insular cortex bilaterally and the right premotor cortex. Compared to the semantic memory tasks, the episodic memory tasks activated the right frontal cortex. These results suggest that cortical networks implicated in semantic and episodic memory show both common and unique regions, with the right prefrontal cortex being the neural correlate specific of episodic remembering.

Adult↗
PubMed1998

Sensitivity and specificity of some neuropsychological markers of Alzheimer dementia.

A standardized neuropsychological test battery was administered to 167 patients with different forms of mild-to-moderate dementia: probable Alzheimer dementia (AD: n = 49), multi-infarct dementia (n = 43), idiopathic Parkinson disease with dementia (n = 35), depressive pseudodementia (n = 26), and progressive supranuclear palsy (n = 14). Results obtained were used (a) to analyze the profiles of cognitive impairment shown by the different dementia groups; (b) to assess the incidence of some neuropsychological patterns that we hypothesized to be more characteristic of AD, in the various groups; and hence (c) to evaluate the reliability of these patterns as diagnostic markers of AD. Four of the patterns investigated were derived from a verbal learning task (Rey's Auditory Verbal Learning test): (1) absence of the primacy effect; (2) tendency to produce intrusion errors during free recall of a word list; (3) absolute decay of memory trace; and (4) tendency to produce false alarms during delayed recognition of the same word list. Two additional patterns were derived from visual-spatial tasks (copying drawings and Raven's Coloured Progressive Matrices): (5) occurrence of the closing-in phenomenon in copying drawings; and (6) tendency to choose globalistic or odd responses in Raven's matrices. Though all the six patterns were somewhat useful for identifying AD patients, no pattern met the criteria of being both highly sensitive and highly specific, which should characterize an ideal marker. In fact, intrusions and false alarms were observed in many AD patients, but also in patients affected by other forms of dementia. The absence of the primacy effect, the closing-in phenomenon, and the absolute decay of memory trace were more specific, but could be observed in only one-third of AD patients. We also computed the number of positive patterns shown by each patient and assumed the presence of two or more patterns as a global index suggestive of a dementia of the Alzheimer type. With this cumulative method, a higher level of sensitivity and specificity was achieved in the identification of AD patients.

Aged↗
PubMed1995

Survival in institutionalized patients. Influence of dementia and loss of functional capacities.

BACKGROUND: Several studies have shown a negative correlation between dementia and survival. To our knowledge, the simultaneous effect of other factors has not been systematically studied in institutionalized patients. OBJECTIVE: To determine survival in demented inpatients compared with that in a matched population of nondemented patients institutionalized for other chronic debilitating diseases. DESIGN: The sample consisted of 213 patients with dementia and 157 patients without dementia. We studied the effect on survival of gender, age, loss of functional capacities, and cognitive functions with the method of Kaplan and Meier and with the model of Cox. RESULTS: Demented patients had significantly shorter survival when other factors were kept constant in the multivariate analysis. There was a strong correlation between survival and the degree of autonomy as measured by ability to walk, continence, and preserved activities of daily living. Survival was significantly shorter for men. No correlation was found with neuropsychological measures of severity of dementia or with age on admission. CONCLUSIONS: Survival of demented patients is shorter than that of patients institutionalized for other invalidating conditions. The lack of correlation between neuropsychological test results and survival indicates that in the population we studied, the severity of dementia did not predict length of survival. The data show that the combination of dementia and loss of functional capacities is the most important factor in predicting survival.

Activities of Daily Living↗
PubMed1995

Anosognosia, intrusions and 'frontal' functions in Alzheimer's disease and depression.

The relationship between anosognosia of memory deficit, intrusions and 'frontal' functions was investigated in 12 Alzheimer (DAT) patients, 12 depressed patients and 24 normal controls. DAT and depressed patients could not be dissociated according to the proportion of intrusion they produced in memory tasks. However, regardless of their clinical diagnosis, patients with anosognosia produced significantly more intrusions than patients without anosognosia, and anosognosia of memory deficit was positively and strongly correlated to the tendency to produce intrusions. By contrast, there was no correlation between intrusions, anosognosia and patients' performance on frontal tasks except for Verbal Fluency. Whereas anosognosia of memory deficit seems indispensable for intrusions, frontal dysfunction must not be considered a necessary condition for intrusions or anosognosia.

Age Factors↗
PubMed1993

Patterns of line bisection in patients suffering from unilateral spatial neglect.

Thirteen patients suffering from Unilateral Spatial Neglect and 6 Right Brain Damaged Control Patients were tested on a line bisection task in order to verify peculiar patterns of error. Stimuli were arranged in order to avoid confounding the effects of line length and line position in the space. Two parameters of rightward displacement of setting point were used: 1) the distance of patient's setting point from actual line midpoint, and 2) the deduced left end-point of the line that patient took into account. Results showed that: 1) the rightward extension of lines did not lead to a consistent rightward displacement of setting point; 2) error significantly increased as lines extended more than 10 cm in the left hemispace; 3) the USN severity amplified the degradation of leftmost portion of stimuli until the deduced left endpoint of all space/length conditions was aligned on the left of patient's sagittal midplane. The interpretation of these results points to the particular arrangement of neurons directing attention on specific portions of the visual field.

Attention↗
PubMed1992

Neuropsychological markers of dementia on visual-spatial tasks: a comparison between Alzheimer's type and vascular forms of dementia.

The incidence of the "closing-in" phenomenon and of the tendency to give "primitive answers" on the Raven's Colored Matrices was studied in 50 normal subjects and in two groups of Alzheimer's type (n = 41) and of vascular (n = 35) dementia patients, carefully matched as for the overall severity of dementia and the degree of visual-spatial impairment. The aims of this research were to determine if these patterns of behavior can be considered as neuropsychological markers of dementia and if their incidence is similar in the two dementia groups. Results show that both the closing-in phenomenon and the tendency to give globalistic and odd responses on the Raven's Colored Matrices are good markers of dementia and that, in particular, they point to a degenerative, rather than to a vascular form of dementia. From the clinical point of view, these data suggest that a qualitative analysis of the patient's behavior can increase the diagnostic efficacy of neuropsychological tests and that neuropsychological markers of dementia point more to Alzheimer's disease (considered as the most prototypic form of dementia) than to a vascular form of dementia even when the two groups of patients are well balanced in terms of visual-spatial impairment and the overall severity of dementia.

Aged↗
PubMedDate not supplied

Specificity of temporal amygdala atrophy in Alzheimer's disease: quantitative assessment with magnetic resonance imaging.

The aim of the study was to assess the specificity of temporal amygdala (TA) atrophy with magnetic resonance imaging (MRI) by comparing a group of early impaired patients with Alzheimer's disease (AD) with 'other types of dementia' and controls. In this prospective case-control study, 41 patients were selected: 12 with probable AD according to NINCDS-ADRDA and CERAD inclusion and exclusion criteria, 14 with other types of dementia and 15 age-matched control subjects. Two radiologists blindly measured the TA volumes on coronal oblique contiguous slices with a 1.5-tesla MRI scanner. TA volume measurements obtained by the 2 observers and right-left TA values were not significantly different. A significant TA atrophy was found in the AD group as compared to the other groups, with 39.7% (p < 0.001) difference in TA volumes between AD and other types of dementia groups and 41.4% (p < 0.0005) difference between AD and control groups. There was no significant difference between other types of dementia and control groups. There was an overlap between the three groups for 4 patients. TA atrophy assessed with MRI could be of diagnostic value in AD, especially in the early stage of the disease.

Aged↗