References of "Perani, Daniela"
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See detailMultivariate analysis of cognitive profiles in Alzheimer's disease
Bastin, Christine ULg; Leclercq, Yves ULg; Collette, Fabienne ULg et al

in Proceedings of the 8th bi-annual Meeting of the Belgian Society for Neuroscience (2009)

The neuropsychological profiles of patients with early Alzheimer’s disease (AD) appear to be heterogeneous. In this study, we examined whether this heterogeneity corresponds to the existence of ... [more ▼]

The neuropsychological profiles of patients with early Alzheimer’s disease (AD) appear to be heterogeneous. In this study, we examined whether this heterogeneity corresponds to the existence of cognitively distinct subtypes of AD or rather to impairments along a continuum of performances in different cognitive domains. A large group of 187 AD patients recruited in the European project NEST-DD performed a neuropsychological battery. A factor analysis of cognitive performance identified three factors, which respectively reflected attentional/instrumental function, declarative memory and executive function. Three clustering methods were applied on the factor scores in order to explore the existence of separate groups. The clustering methods indicated that cognitive profiles among the patients were sufficiently variable to identify clusters, but there was continuity between clusters rather than clear-cut subtypes. Moreover, clusters corresponded to various combinations of relatively impaired and preserved functions, suggesting multidimensional distribution within a large population of patients. Finally, clusters of cognitive profiles were characterized by different levels of metabolism in brain regions commonly (but variably) involved or relatively preserved in AD. [less ▲]

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See detailOn the multivariate nature of brain metabolic impairment in Alzheimer’s disease
Salmon, Eric ULg; Kerrouche, Nacer; Perani, Daniela et al

in Neurobiology of Aging (2009), 30

We used principal component analysis to decompose functional images of patients with AD in orthogonal ensembles of brain regions with maximal metabolic covariance. Three principal components explained 38 ... [more ▼]

We used principal component analysis to decompose functional images of patients with AD in orthogonal ensembles of brain regions with maximal metabolic covariance. Three principal components explained 38% of the total variance in a large sample of FDG-PET images obtained in 225 AD patients. One functional ensemble (PC2) included limbic structures from Papez's circuit (medial temporal regions, posterior and anterior cingulate cortex, thalamus); its disruption in AD patients was related to episodic memory impairment. Another principal component (PC1) illustrated major metabolic variance in posterior cerebral cortices, and patients' scores were correlated to instrumental functions (language and visuospatial abilities). PC3 comprised frontal, parietal, temporal and posteromedial (posterior cingulate and precuneus) cortices, and patients' scores were related to executive dysfunction and global cognitive impairment. The three main metabolic covariance networks converged in the posterior cingulate area that showed complex relationships with medial temporal structures within each PC. Individual AD scores were distributed as a continuum along PC axes: an individual combination of scores would determine specific clinical symptoms in each patient. [less ▲]

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See detailA Comparison of Unawareness in Frontotemporal Dementia and Alzheimer's Disease
Salmon, Eric ULg; Perani, Daniela; Collette, Fabienne ULg et al

in Journal of Neurology, Neurosurgery & Psychiatry (2008), 79(2), 176-9

BACKGROUND: Loss of insight is a core diagnostic feature of frontotemporal dementia (FTD) and anosognosia is frequently reported in Alzheimer's disease (AD). AIM: To compare unawareness (anosognosia) for ... [more ▼]

BACKGROUND: Loss of insight is a core diagnostic feature of frontotemporal dementia (FTD) and anosognosia is frequently reported in Alzheimer's disease (AD). AIM: To compare unawareness (anosognosia) for different symptoms, measured with a discrepancy score between patient's and caregiver's assessment, in AD and FTD. METHOD: In a prospective, multi-centre study, 123 patients with probable AD, selected according to the NINCDS-ADRDA procedure, were matched for age, sex, education, disease duration and dementia severity to patients with FTD (n = 41), selected according to international consensus criteria. A research complaint questionnaire was used to obtained patient's and caregiver's assessment concerning neuropsychological and behavioural symptoms. Data were compared in each group and between groups. Unawareness (measured by discrepancy scores) was compared between patients with AD and FTD. RESULTS: The caregivers generally assessed symptoms more severely than did patients, but both patient groups reported changes in affect (depressive mood or irritability) as their caregivers did. Unawareness was greater in patients with FTD than in patients with AD for language and executive difficulties, and for changes in behaviour and daily activities. CONCLUSION: The main finding is that unawareness was observed in both patients with FTD and patients with AD for most clinical domains. However, qualitative and quantitative differences showed that lack of awareness was greater in patients with FTD. [less ▲]

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See detailDecomposition of metabolic brain clusters in the frontal variant of frontotemporal dementia
Salmon, Eric ULg; Kerrouche, Nacer; Herholz, Karl et al

in NeuroImage (2006), 30(3), 871-878

Previous studies that measured brain activity in frontotemporal dementia (FTD) used univariate analyses, examining each region of interest separately. We explored in a multicenter European research ... [more ▼]

Previous studies that measured brain activity in frontotemporal dementia (FTD) used univariate analyses, examining each region of interest separately. We explored in a multicenter European research program the principal brain clusters characterized by a common variability in cerebral metabolism in FTD. Seventy patients with frontal variant (fv) FTD were selected according to international clinical recommendations; principal component analysis (PCA) was performed on FDG-PET metabolic images, looking for covariance clusters in this large population. A first metabolic cluster included most of the lateral and medial prefrontal cortex, bilaterally; PC1 scores correlated with performances on memory and executive neuropsychological tasks. Moreover, FDG-PET images in fv-FTD were further characterized by a metabolic covariance in two clusters comprising the subcallosal medial frontal region, the temporal pole, medial temporal structures and the striatum, separately in the left and in the right hemisphere. The study provides original data-driven arguments for metabolic involvement of separate brain clusters in the rostral limbic system, corresponding to pathological poles differentially affected in each FTD patient. [less ▲]

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See detailOrbitofrontal dysfunction related to both apathy and disinhibition in frontotemporal dementia
Peters, Frederic; Perani, Daniela; Herholz, Karl et al

in Dementia & Geriatric Cognitive Disorders (2006), 21(5-6), 373-379

Orbitofrontal metabolic impairment is characteristic of the frontal variant of frontotemporal dementia (fv-FTD), as are early changes in emotional and social conduct. Two main types of behavioral ... [more ▼]

Orbitofrontal metabolic impairment is characteristic of the frontal variant of frontotemporal dementia (fv-FTD), as are early changes in emotional and social conduct. Two main types of behavioral disturbances have been distinguished in fv-FTD patients: apathetic and disinhibited manifestations. In this study, we searched for relationships between brain metabolism and presence of apathetic or disinhibited behavior. Metabolic activity and behavioral data were collected in 41 fv-FTD patients from European PET centers. A conjunction analysis of the PET data showed an expected impairment of metabolic activity in the anterior cingulate, ventromedial and orbital prefrontal cortex, the dorsolateral prefrontal cortex and the left anterior insula in fv-FTD subjects compared to matched controls. A correlation was observed between disinhibition scores on the Neuropsychiatric Inventory scale and a cluster of voxels located in the posterior orbitofrontal cortex ( 6, 28, - 24). Comparison of brain activity between apathetic and nonapathetic fv-FTD patients from two centers also revealed a specific involvement of the posterior orbitofrontal cortex in apathetic subjects ( 4, 22, - 22). The results confirm that the main cerebral metabolic impairment in fv-FTD patients affects areas specializing in emotional evaluation and demonstrate that decreased orbitofrontal activity is related to both disinhibited and apathetic syndromes in fv-FTD. Copyright (C) 2006 S. Karger AG, Basel. [less ▲]

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See detailCerebral metabolic correlates of four dementia scales in Alzheimer's disease
Salmon, Eric ULg; Lespagnard, Solange ULg; Marique, Patricia et al

in Journal of Neurology (2005), 252(3), 283-290

Different scales can be used to evaluate dementia severity in Alzheimers disease (AD). They do assess different cognitive or functional abilities, but their global scores are frequently in mutual ... [more ▼]

Different scales can be used to evaluate dementia severity in Alzheimers disease (AD). They do assess different cognitive or functional abilities, but their global scores are frequently in mutual correlation. Functional imaging provides an objective method for the staging of dementia severity. Positron emission tomography was used to assess the relationship between brain metabolism and four dementia scales that reflect a patients global cognitive abilities (mini mental state), caregivers evaluation of cognitive impairment (newly designed scale), daily living functioning (instrumental activities of daily living) and global dementia (clinical dementia rating). We wondered whether different clinical dementia scales would be related to severity of metabolic impairment in the same brain regions, and might reflect impairment of common cognitive processes. 225 patients with probable AD were recruited in a prospective multicentre European study. All clinical scales were related to brain metabolism in associative temporal, parietal or frontal areas. A factorial analysis demonstrated that all scales could be classified in a single factor. That factor was highly correlated to decrease of cerebral activity in bilateral parietal and temporal cortices, precuneus, and left middle frontal gyrus. This finding suggests that global scores for all scales provided similar information on the neural substrate of dementia severity. Capitalizing on the neuroimaging literature, dementia severity reflected by reduced metabolism in posterior and frontal associative areas in AD might be related to a decrease of controlled processes. [less ▲]

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See detailTwo Aspects of Impaired Consciousness in Alzheimer's Disease
Salmon, Eric ULg; Ruby, Perrine; Perani, Daniela et al

in Progress in Brain Research (2005), 150(Boundaries of Consciousness: Neurobiology and Neuropathology), 287-98

Alzheimer's disease (AD) is a degenerative dementia characterized by different aspects of impaired consciousness. For example, there is a deficit of controlled processes that require conscious processing ... [more ▼]

Alzheimer's disease (AD) is a degenerative dementia characterized by different aspects of impaired consciousness. For example, there is a deficit of controlled processes that require conscious processing of information. Such an impairment is indexed by decreased performances at controlled cognitive tasks, and it is related to reduced brain metabolic activity in a network of frontal, posterior associative, and limbic regions. Another aspect of impaired consciousness is that AD patients show variable levels of anosognosia concerning their cognitive deficits. A discrepancy score between patient's and caregiver's assessment of cognitive functions is one of the most frequently used measures of anosognosia. A high discrepancy score has been related to impaired activity in the superior frontal sulcus and the parietal cortex in AD. Anosognosia for cognitive deficits in AD could be partly explained by impaired metabolism in parts of networks subserving self-referential processes (e.g., the superior frontal sulcus) and perspective-taking (e.g., the temporoparietal junction). We hypothesize that these patients are impaired in the ability to see themselves with a third-person perspective (i.e., being able to see themselves as other people see them). [less ▲]

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See detailPredominant ventromedial frontopolar metabolic impairment in frontotemporal dementia
Salmon, Eric ULg; Garraux, Gaëtan ULg; Delbeuck, Xavier et al

in NeuroImage (2003), 20(1), 435-440

In a multicenter study, FDG-PET images in a population of 29 patients with frontotemporal dementia (FTD) were compared to controls with similar age from each center. A conjunction analysis led to ... [more ▼]

In a multicenter study, FDG-PET images in a population of 29 patients with frontotemporal dementia (FTD) were compared to controls with similar age from each center. A conjunction analysis led to identification of the ventromedial frontopolar cortex as the single region affected in each and every FTD patients. This precise regional metabolic impairment should be integrated with recent neuropsychological researches, such as those showing that the ventromedial frontal cortex is critically involved in decision-making processes based on personal experience, feelings of rightness or social knowledge, processes that are characteristically impaired in FTD. (C) 2003 Elsevier Inc. All rights reserved. [less ▲]

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