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Daniela Perani

Publications and source records attributed to Daniela Perani.

At least 19 recordsLinked to original sources
PubMed2026

Predicting training outcomes for developmental dyslexia from EEG data.

Developmental dyslexia (DD) is characterised by lower-than-average reading abilities and is diagnosed in approximately 10% of individuals. The societal barriers may limit professional fulfilment and psychological wellbeing of individuals with DD, calling for the development of effective interventions to counteract them. As DD is associated with challenges in both phonological and visuo-attentional domains, different longitudinal training approaches were developed to strengthen them. However, they require a considerable amount of personal, social and economic resources and the outcomes may vary depending on individual differences in behavioural and neurophysiological functionality. Hence, predicting training outcomes might help in developing personalised treatment protocols and optimising the use of resources. In the present work we applied machine learning to resting-state EEG to predict longitudinal training outcomes in adults with DD enrolled in a randomized clinical trial. In particular, one group received a visuo-attentional training combined with transcranial alternating current stimulation (tACS), another group received visuo-attentional training with sham/placebo stimulation, and the third group received a phonological training with sham/placebo stimulation. The improvement in text reading speed was associated with spectral power in low-beta and individual frequencies in the alpha (IAF) and beta (IBF) bands, while the improvement in pseudoword reading was associated with IBF. The findings highlight the potential of capturing neural markers of treatment responsiveness in DD. Future studies should focus on the generalisability of predictive models to real-world settings, while investigating whether specific EEG markers predict responsiveness to distinct remediation protocols, thus supporting the development of personalised interventions.

Humans↗
PubMed2007

Late acquisition of literacy in a native language.

With event-related functional MRI (fMRI) and with behavioral measures we studied the brain processes underlying the acquisition of native language literacy. Adult dialect speakers were scanned while reading words belonging to three different conditions: dialect words, i.e., the native language in which subjects are illiterate (dialect), German words, i.e., the second language in which subjects are literate, and pseudo-words. Investigating literacy acquisition of a dialect may reveal how novel readers of a language build an orthographic lexicon, i.e., establish a link between already available semantic and phonological representations and new orthographic word forms. The main results of the study indicate that a set of regions, including the left anterior hippocampal formation and subcortical nuclei, is involved in the buildup of orthographic representations. The repeated exposure to written dialect words resulted in a convergence of the neural substrate to that of the language in which these subjects were already proficient readers. The latter result is compatible with a "fast" brain plasticity process that may be related to a shift of reading strategies.

Adult↗
PubMed2006

Fluvoxamine treatment and D2 receptors: a pet study on OCD drug-naïve patients.

Changes in D(2) receptors during antidepressant therapy have been reported in patients with major depressive disorder using PET/SPET. The aim of this study was to evaluate modifications in D(2) receptors that might occur in patients affected by obsessive-compulsive disorder (OCD) during serotonin reuptake sites inhibitors (SSRIs). To this purpose, we measured the in vivo binding of [(11)C]raclopride ([(11)C]Rac)in the brain of a group of OCD naïve patients before and after the repeated administration of the inhibitor SSRI fluvoxamine. Eight patients with a Diagnostic and Statistical Manual of Mental Disorders IVth edition diagnosis of OCD completed the study undergoing a PET scan and a complete clinical evaluation before and during treatment with fluvoxamine. Patients have been compared also with a group of nine age-matched normal volunteers. Fluvoxamine treatment significantly improved clinical symptoms and increased [(11)C]Rac binding potential (BP) in the basal ganglia of OCD patients (7.5+/-5.2, 6.9+/-6.9, and 9.9+/-9.3% in dorsal caudate, dorsal putamen, and ventral basal ganglia, respectively; p<0.01) to values closer to those observed in the group of normal subjects. Chronic treatment with fluvoxamine induces a slight but significant increase in striatal [(11)C]Rac BP of previously drug-naïve OCD patients. The modifications in D(2) receptor availability might be secondary to fluvoxamine effects on serotoninergic activity.

Adult↗
PubMed2006

The impact of semantic reference on word class: an fMRI study of action and object naming.

There is a considerable body of neuropsychological and neuroimaging evidence supporting the distinction between the brain correlates of noun and verb processing. It is however still not clear whether the observed differences are imputable to grammatical or semantic factors. Beyond the basic difference that verbs typically refer to actions and nouns typically refer to objects, other semantic distinctions might play a role as organizing principles within and across word classes. One possible candidate is the notion of manipulation and manipulability, which may modulate the word class dissociation. We used functional magnetic resonance imaging (fMRI) to study the impact of semantic reference and word class on brain activity during a picture naming task. Participants named pictures of objects and actions that did or did not involve manipulation. We observed extensive differences in activation associated with the manipulation dimension. In the case of manipulable items, for both nouns and verbs, there were significant activations within a fronto-parietal system subserving hand action representation. However, we found no significant effect of word class when all verbs were compared to all nouns. These results highlight the impact of the biologically crucial sensorimotor dimension of manipulability on the pattern of brain activity associated to picture naming.

Adult↗
PubMed2006

Functional correlates of Apolipoprotein E genotype in Frontotemporal Lobar Degeneration.

BACKGROUND: It has been recently demonstrated that in Frontotemporal Lobar Degeneration (FTLD) memory deficits at presentation are commoner than previously thought. Apolipoprotein E (ApoE) genotype, the major genetic risk factor in sporadic late-onset Alzheimer Disease (AD), modulates cerebral perfusion in late middle-age cognitively normal subjects. ApoE epsilon4 homozygous have reduced glucose metabolism in the same regions involved in AD. The aim of this study was to determine whether ApoE genotype might play a key-role in influencing the cerebral functional pattern as well as the degree of memory deficits in FTLD patients. METHODS: Fifty-two unrelated FTLD patients entered the study and underwent a somatic and neurological evaluation, laboratory examinations, a brain structural imaging study, and a brain functional Single Photon Emission Tomography study. ApoE genotype was determined. RESULTS: ApoE genotype influenced both clinical and functional features in FTLD. ApoE epsilon4-carriers were more impaired in long-term memory function (ApoE epsilon4 vs. ApoE non epsilon4, 6.3 +/- 3.9 vs. 10.1 +/- 4.2, p = 0.004) and more hypoperfused in uncus and parahippocampal regions (x,y,z = 38,-6,-20, T = 2.82, cluster size = 100 voxels; -32,-12,-28, T= 2.77, cluster size = 40 voxels). CONCLUSION: The present findings support the view that ApoE genotype might be considered a disease-modifying factor in FTLD, thus contributing to define a specific clinical presentation, and might be of relevance for pharmacological approaches.

Adult↗
PubMed2006

Neuropsychological deficits and neural dysfunction in familial dyslexia.

We report the neuropsychological profile and the pattern of brain activity during reading tasks in a sample of familial dyslexics. We studied our subjects with an in-depth neuropsychological assessment and with functional neuroimaging (fMRI) during word and pseudoword reading and false font string observations (baseline condition). The neuropsychological assessment revealed that familial dyslexia, in both persistent and compensated forms, is often associated with deficits in verbal short-term memory, phonological awareness and automatization abilities. The functional results showed a lack of activation in the posterior areas of the reading network. This study, together with the previously published VBM study (Brambati, S.M., Termine, C., Ruffino, M., Stella, G., Fazio, F., Cappa, S.F. and Perani, D., Regional reductions of gray matter volume in familial dyslexia, Neurology, 63 (2004) 742-5), provides a multiple modality evaluation of familial dyslexia. The neuropsychological assessment showed cognitive deficits associated with dyslexia that persist also in subjects with compensated reading deficit. Both the anatomical and the functional study point out a deficit in the posterior areas of the reading network.

Adolescent↗
PubMed2006

Orbitofrontal dysfunction related to both apathy and disinhibition in frontotemporal dementia.

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.

Aged↗
PubMed2006

Development of saccadic suppression in children.

We measured saccadic suppression in adolescent children and young adults using spatially curtailed low spatial frequency stimuli. For both groups, sensitivity for color-modulated stimuli was unchanged during saccades. Sensitivity for luminance-modulated stimuli was greatly reduced during saccades in both groups but far more for adolescents than for young adults. Adults' suppression was on average a factor of about 3, whereas that for the adolescent group was closer to a factor of 10. The specificity of the suppression to luminance-modulated stimuli excludes generic explanations such as task difficulty and attention. We suggest that the enhanced suppression in adolescents results from the immaturity of the ocular-motor system at that age.

Adolescent↗
PubMed2006

Pre-symptomatic diagnosis in fatal familial insomnia: serial neurophysiological and 18FDG-PET studies.

Knowing how and when the degenerative process starts is important in neurodegenerative diseases. We have addressed this issue in fatal familial insomnia (FFI) measuring the cerebral metabolic rate of glucose (CMRglc) with 2-[18F]fluoro-2-deoxy-D-glucose PET in parallel with detailed clinical, neuropsychological examinations and polysomnography with EEG spectral analyses. Nine asymptomatic carriers of the D178N mutation, 10 non-carriers belonging to the same family, and 19 age-matched controls were studied over several years. The CMRglc as well as clinical and electrophysiological examinations were normal in all cases at the beginning of the study. Four of the mutation carriers developed typical FFI during the study but CMRglc and the clinical and electrophysiological examinations remained normal 63, 56, 32 and 21 months, respectively before disease onset. The carrier whose tests were normal 32 months before disease onset was re-examined 13 months before the onset. At that time, selective hypometabolism was detected in the thalamus while spectral-EEG analysis disclosed an impaired thalamic sleep spindle formation. Following clinical disease onset, CRMglc was reduced in the thalamus in all 3 patients examined. Our data indicate that the neurodegenerative process associated with FFI begins in the thalamus between 13 and 21 months before the clinical presentation of the disease.

Adult↗
PubMed2006

Neural correlates of anosognosia for cognitive impairment in Alzheimer's disease.

We explored the neural substrate of anosognosia for cognitive impairment in Alzheimer's disease (AD). Two hundred nine patients with mild to moderate dementia and their caregivers assessed patients' cognitive impairment by answering a structured questionnaire. Subjects rated 13 cognitive domains as not impaired or associated with mild, moderate, severe, or very severe difficulties, and a sum score was calculated. Two measures of anosognosia were derived. A patient's self assessment, unconfounded by objective measurements of cognitive deficits such as dementia severity and episodic memory impairment, provided an estimate of impaired self-evaluative judgment about cognition in AD. Impaired self-evaluation was related to a decrease in brain metabolism measured with 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) in orbital prefrontal cortex and in medial temporal structures. In a cognitive model of anosognosia, medial temporal dysfunction might impair a comparison mechanism between current information on cognition and personal knowledge. Hypoactivity in orbitofrontal cortex may not allow AD patients to update the qualitative judgment associated with their impaired cognitive abilities. Caregivers perceived greater cognitive impairments than patients did. The discrepancy score between caregiver's and patient's evaluations, an other measure of anosognosia, was negatively related to metabolic activity located in the temporoparietal junction, consistent with an impairment of self-referential processes and perspective taking in AD.

Aged↗
PubMed2005

Decomposition of metabolic brain clusters in the frontal variant of frontotemporal dementia.

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.

Adult↗
PubMed2005

Pre-clinical diagnosis of Alzheimer disease combining platelet amyloid precursor protein ratio and rCBF spect analysis.

Platelet Amyloid Precursor Protein ratio of different abnormal forms and 99mTc-ECD SPECT perfusion analysis were evaluated in Mild Cognitive Impairment (MCI) subjects who progressed to Alzheimer Disease (AD) and in stable MCI. We report that their combined evaluation increases the discriminative power of the analysis in identifying presymptomatic AD. The positive predictive value of these combined markers in identifying progressive MCI was 0.87, and the negative predictive value was 0.90. This observation suggests that the interplay of different markers should be considered for enhancing diagnostic accuracy of pre-clinical AD.

Aged↗
PubMed2005

Basal ganglia and language: phonology modulates dopaminergic release.

Basal ganglia have been implicated in syntactic and phonological processes, but direct evidence has been scarce. Here, we used [11C]raclopride and positron emission tomography to measure modulations of the dopaminergic system induced by phonological or syntactic processing. Two significant effects were found. First, the level of accuracy in phonological processing significantly correlated with tracer binding potential in the left caudate nucleus. Second, the speed in phonological processing significantly correlated with tracer binding potential in the left putamen. Thus, a more accurate and fast phonological processing was associated with a reduced dopamine requirement in the left striatum. These findings show that the striatal dopaminergic system plays an essential role in grammatical processes that form the core of human language.

Acoustic Stimulation↗
PubMed2005

Heterogeneity of brain glucose metabolism in mild cognitive impairment and clinical progression to Alzheimer disease.

BACKGROUND: Subjects with amnesic mild cognitive impairment (aMCI) may include patients at high risk for progression to Alzheimer disease (AD) and a population with different underlying pathologic conditions. OBJECTIVE: To evaluate the potential roles of positron emission tomography with fluorodeoxyglucose F 18 (18FDG-PET) and memory scores in identifying subjects with aMCI and in predicting progression to dementia. DESIGN, SETTING, AND PATIENTS: Sixty-seven patients at European centers for neurologic and AD care who were diagnosed as having aMCI each underwent an extensive clinical and neuropsychological examination and an 18FDG-PET study. Forty-eight subjects were followed up periodically for at least 1 year, and progression to dementia was evaluated. MAIN OUTCOME MEASURES: Brain glucose metabolism and memory scores. RESULTS: Fourteen subjects with aMCI who converted to AD within 1 year showed bilateral hypometabolism in the inferior parietal, posterior cingulate, and medial temporal cortex. Subjects with "stable" aMCI presented with hypometabolism in the dorsolateral frontal cortex. The severity of memory impairment, as evaluated by the California Verbal Learning Test-Long Delay Free Recall scores, correlated with the following brain metabolic patterns: scores less than 7 were associated with a typical 18FDG-PET AD pattern, and scores of 7 or higher were associated with hypometabolism in the dorsolateral frontal cortex and no progression to AD. CONCLUSION: These data provide evidence for clinical and functional heterogeneity among subjects with aMCI and suggest that 18FDG-PET findings combined with memory scores may be useful in predicting short-term conversion to AD.

Aged↗
PubMed2005

Glucose metabolism and serotonin receptors in the frontotemporal lobe degeneration.

In patients with the frontal variant of frontotemporal lobar degeneration (fv-FTLD), behavioral abnormalities may vary from apathy with motor slowness (apathetic form) to disinhibition with agitation (disinhibited form). These clinical presentations may be related to specific regional cerebral dysfunction and to deficit in the serotoninergic system. We studied cerebral glucose uptake using (18)F-fluorodeoxyglucose and positron emission tomography in 18 patients fulfilling clinical criteria for fv-FTLD and showing, respectively, an apathetic or disinhibited behavioral syndrome. In eight of these patients, we also evaluated the 5-hydroxytryptamine-2A receptor cerebral receptor distribution with [(11)C]MDL and positron emission tomography. We found a reduction of frontal glucose metabolism in the whole group of fv-FTLD patients. Apathetic syndrome was associated with a prevalent dorsolateral and frontal medial hypometabolism, whereas the disinhibited syndrome demonstrated a selective hypometabolism in interconnected limbic structures (the cingulate cortex, hippocampus/amygdala, and accumbens nucleus). The in vivo measurements of [(11)C]MDL indicated a significant reduction of 5-hydroxytryptamine-2A receptors in orbitofrontal, frontal medial, and cingulate cortices. These (18)F-fluorodeoxyglucose positron emission tomography changes can be considered as specific functional markers of the different behavioral presentations in fv-FTLD. The serotoninergic system dysfunction provides a rationale for therapeutic trials with selective serotonin reuptake inhibitors.

Aged↗
PubMed2005

The effect of social content on deductive reasoning: an fMRI study.

Psychological studies of deductive reasoning have shown that subjects' performance is affected significantly by the content of the presented stimuli. Specifically, subjects find it easier to reason about contexts and situations with a social content. In the present study, the effect of content on brain activation was investigated with functional magnetic resonance imaging (fMRI) while subjects were solving two versions of the Wason selection task, which previous behavioral studies have shown to elicit a significant content effect. One version described an arbitrary relation between two actions (Descriptive: "If someone does ..., then he does ..."), whereas the other described an exchange of goods between two persons (Social-Exchange: "If you give me ..., then I give you ..."). Random-effect statistical analyses showed that compared to baseline, both tasks activated frontal medial cortex and left dorsolateral frontal and parietal regions, confirming the major role of the left hemisphere in deductive reasoning. In addition, although the two reasoning conditions were identical in logical form, the social-exchange task was also associated with right frontal and parietal activations, mirroring the left-sided activations common to both reasoning tasks. These results suggest that the recruitment of the right hemisphere is dependent on the content of the stimuli presented.

Adult↗
PubMed2005

Generating animal and tool names: an fMRI study of effective connectivity.

The present fMRI study of semantic fluency for animal and tool names provides further evidence for category-specific brain activations, and reports task-related changes in effective connectivity among defined cerebral regions. Two partially segregated systems of functional integration were highlighted: the tool condition was associated with an enhancement of connectivity within left hemispheric regions, including the inferior prefrontal and premotor cortex, the inferior parietal lobule and the temporo-occipital junction; the animal condition was associated with greater coupling among left visual associative regions. These category-specific functional differences extend the evidence for anatomical specialization to lexical search tasks, and provide for the first time evidence of category-specific patterns of functional integration in word-retrieval.

Association Learning↗