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S F Cappa

Publications and source records attributed to S F Cappa.

At least 19 recordsLinked to original sources
PubMed2003

Cognitive dysfunction in patients with obstructive sleep apnea (OSA): partial reversibility after continuous positive airway pressure (CPAP).

The aims of this study were to assess cognitive function in obstructive sleep apnea (OSA) patients and to evaluate the effect of short- and long-term treatment with continuous positive airway pressure treatment (CPAP). A battery of neuropsychological tests, the Epworth Sleepiness Scale (ESS), and the Beck Inventory Scale were administered to 23 patients with severe OSA (age: 56.5+/-6.13; AHI: 54.9+/-13.37) and to 23 age- and education-matched controls. The OSA patients were evaluated in a baseline condition and in two follow-up treatment sessions (after 15 days and 4 months of CPAP, respectively). At baseline, OSA patients had a significant impairment, compared to controls, in tests of sustained attention, visuospatial learning, executive function, motor performance, and constructional abilities. The longitudinal evaluation showed that after a 15-days CPAP treatment attentive, visuospatial learning, and motor performances returned to normal levels. A 4-months CPAP treatment did not result in any further improvement in cognitive tests. Performance on tests evaluating executive functions and constructional abilities was not affected by short- and long-term treatment with CPAP. The findings of this study confirm the hypothesis of partial reversibility of cognitive dysfunction in OSA patients after CPAP.

Attention↗
PubMed2003

A fMRI study of word retrieval in aphasia.

The neural mechanisms underlying recovery of cognitive functions are incompletely understood. Aim of this study was to assess, using functional magnetic resonance (fMRI), the pattern of brain activity during covert word retrieval to letter and semantic cues in five aphasic patients after stroke, in order to assess the modifications of brain function which may be related to recovery. Four out of five patients had undergone language recovery, according to standard testing, after at least 6 months of rehabilitation. The cerebral activation of each patient was evaluated and compared with the activation pattern of normal controls studied with the same fMRI paradigm. In the patients, the pattern of brain activation was influenced by the site and extent of the lesion, by the degree of recovery of language, as reflected by task performance outside the scanner, and by task requirements. In the case of word retrieval to letter cues, a good performance was directly related to the activation in Broca's area, or in the right-sided homologue. On the other hand, in the case of semantic fluency, the relationship between performance level and activation was less clear-cut, because of extensive recruitment of frontal areas in patients with defective performance. These findings suggest that the performance in letter fluency is dependent on the integrity of the left inferior frontal cortex, with the participation of the homologous right hemispheric region when the left inferior frontal cortex is entirely of partially damaged. Semantic fluency, which engages the distributed network of semantic memory, is also associated with more extensive patterns of cerebral activation, which however appear to reflect retrieval effort rather than retrieval success.

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PubMed2003

EFNS guidelines on cognitive rehabilitation: report of an EFNS task force.

In 1999, a Task Force was set up under the auspices of the European Federation of Neurological Societies with the aim to evaluate the existing evidence for the clinical effectiveness of cognitive rehabilitation. This review led to the development of a set of guidelines to be used in the management of adult patients with cognitive disorders due to acquired focal neurological damage.

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PubMed2002

The role of the left frontal lobe in action naming: rTMS evidence.

BACKGROUND: Neuropsychological and neuroimaging studies suggest that whereas the left temporal neocortex plays a crucial role in all tasks involving lexical-semantic processing, some regions of the left prefrontal convexity are selectively recruited during verb processing. OBJECTIVE: To determine if there are different neural correlates for noun and verb processing in the human brain. METHODS: Repetitive transcranial magnetic stimulation (rTMS), 20 Hz at 90% of the motor threshold, was applied to left or right prefrontal brain during object- and action-naming tasks in nine healthy subjects. RESULTS: A shortening of naming latency for actions was observed only after stimulation of left prefrontal cortex. CONCLUSION: The involvement of the left dorsolateral frontal cortex in action naming was demonstrated using rTMS.

Adult↗
PubMed2001

Dyslexia: cultural diversity and biological unity.

The recognition of dyslexia as a neurodevelopmental disorder has been hampered by the belief that it is not a specific diagnostic entity because it has variable and culture-specific manifestations. In line with this belief, we found that Italian dyslexics, using a shallow orthography which facilitates reading, performed better on reading tasks than did English and French dyslexics. However, all dyslexics were equally impaired relative to their controls on reading and phonological tasks. Positron emission tomography scans during explicit and implicit reading showed the same reduced activity in a region of the left hemisphere in dyslexics from all three countries, with the maximum peak in the middle temporal gyrus and additional peaks in the inferior and superior temporal gyri and middle occipital gyrus. We conclude that there is a universal neurocognitive basis for dyslexia and that differences in reading performance among dyslexics of different countries are due to different orthographies.

Adult↗
PubMed2001

Syntax and the brain: disentangling grammar by selective anomalies.

Many paradigms employed so far with functional imaging in language studies do not allow a clear differentiation of the semantic, morphological, and syntactic components, as traditionally defined within linguistic theory. In fact, many studies simply consider the brain's response to lists of unrelated words, rather than to syntactic structures, or do not neutralize the confounding effect of the semantic component. In the present PET experiment, we isolated the functional correlates of morphological and syntactic processing. The neutralization of the access to the lexical-semantic component was achieved by requiring the detection of anomalies in written sentences consisting of pseudowords. In both syntactic and morphosyntactic processing, the involvement of a selective deep component of Broca's area and of a right inferior frontal region was detected. In addition, within this system, the left caudate nucleus and insula were activated only during syntactic processing, indicating their role in syntactic computation. These findings provide original in vivo evidence that these brain structures, whose individual contribution has been highlighted by clinical studies, constitute a neural network selectively engaged in morphological and syntactic computation.

Adult↗
PubMed2001

Prefrontal [correction of Prefontal] cortex in long-term memory: an "interference" approach using magnetic stimulation.

Neuroimaging has consistently shown engagement of the prefrontal cortex during episodic memory tasks, but the functional relevance of this metabolic/hemodynamic activation in memory processing is still to be determined. We used repetitive transcranial magnetic stimulation (rTMS) to transiently interfere with either left or right prefrontal brain activity during the encoding or retrieval of pictures showing complex scenes. We found that the right dorsolateral prefrontal cortex (DLPFC) was crucial for the retrieval of the encoded pictorial information, whereas the left DLPFC was involved in encoding operations. This 'interference' approach allowed us to establish whether a cortical area activated by a memory task actually contributes to behavioral performance.

Adult↗
PubMed2001

A brief neuropsychological assessment for the differential diagnosis between frontotemporal dementia and Alzheimer's disease.

The neuropsychological performance (including measures of language, semantic memory, visual and spatial perception and executive functions) of a group of 14 patients with the clinical diagnosis of probable frontotemporal dementia was compared with that of a group of 14 patients with a clinical diagnosis of probable Alzheimer's disease. The aim was to identify a specific cognitive profile of frontotemporal dementia, which could be used to select a sensitive, short evaluation for the differential diagnosis with Alzheimer's disease. Both groups were severely impaired in most tasks, including those 'frontal lobe' tests which have been suggested to play an important role in differential diagnosis. Significant differences were found only for a minority of tests (oral praxis, visual-spatial perception, and verbal fluency). A logistic regression showed that a shortened testing procedure based on four tests (Rey-Osterreith complex figure test recall, phonemic fluency, oral apraxia, and cube analysis) achieved a 70% sensitivity and 80% specificity for the correct classification of patients in the frontotemporal dementia or Alzheimer's disease group. In conclusion, a brief neuropsychological evaluation including these four tests, as well as other measures sensitive to the frontal impairment, can be useful in the differential diagnosis between the two pathologies, along with the clinical data.

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PubMed2000

A cultural effect on brain function.

We present behavioral and anatomical evidence for a multi-component reading system in which different components are differentially weighted depending on culture-specific demands of orthography. Italian orthography is consistent, enabling reliable conversion of graphemes to phonemes to yield correct pronunciation of the word. English orthography is inconsistent, complicating mapping of letters to word sounds. In behavioral studies, Italian students showed faster word and non-word reading than English students. In two PET studies, Italians showed greater activation in left superior temporal regions associated with phoneme processing. In contrast, English readers showed greater activations, particularly for non-words, in left posterior inferior temporal gyrus and anterior inferior frontal gyrus, areas associated with word retrieval during both reading and naming tasks.

Adult↗
PubMed1999

Word and picture matching: a PET study of semantic category effects.

We report two positron emission tomography (PET) studies of cerebral activation during picture and word matching tasks, in which we compared directly the processing of stimuli belonging to different semantic categories (animate and inanimate) in the visual (pictures) and verbal (words) modality. In the first experiment, brain activation was measured in eleven healthy adults during a same/different matching task for textures, meaningless shapes and pictures of animals and artefacts (tools). Activations for meaningless shapes when compared to visual texture discrimination were localized in the left occipital and inferior temporal cortex. Animal picture identification, either in the comparison with meaningless shapes and in the direct comparison with non-living pictures, involved primarily activation of occipital regions, namely the lingual gyrus bilaterally and the left fusiform gyrus. For artefact picture identification, in the same comparison with meaningless shape-baseline and in the direct comparison with living pictures, all activations were left hemispheric, through the dorsolateral frontal (Ba 44/6 and 45) and temporal (Ba 21, 20) cortex. In the second experiment, brain activation was measured in eight healthy adults during a same/different matching task for visually presented words referring to animals and manipulable objects (tools); the baseline was a pseudoword discrimination task. When compared with the tool condition, the animal condition activated posterior left hemispheric areas, namely the fusiform (Ba 37) and the inferior occipital gyrus (Ba 18). The right superior parietal lobule (Ba 7) and the left thalamus were also activated. The reverse comparison (tools vs animals) showed left hemispheric activations in the middle temporal gyrus (Ba 21) and precuneus (Ba 7), as well as bilateral activation in the occipital regions. These results are compatible with different brain networks subserving the identification of living and non-living entities; in particular, they indicate a crucial role of the left fusiform gyrus in the processing of animate entities and of the left middle temporal gyrus for tools, both from words and pictures. The activation of other areas, such as the dorsolateral frontal cortex, appears to be specific for the semantic access of tools only from pictures.

Adult↗
PubMed1999

The neural correlates of verb and noun processing. A PET study.

The hypothesis that categorical information, distinguishing among word classes, such as nouns, verbs, etc., is an organizational principle of lexical knowledge in the brain, is supported by the observation of aphasic subjects who are selectively impaired in the processing of nouns and verbs. The study of lesion location in these patients has suggested that the left temporal lobe plays a crucial role in processing nouns, while the left frontal lobe is necessary for verbs. To delineate the brain areas involved in the processing of different word classes, we used PET to measure regional cerebral activity during tasks requiring reading of concrete and abstract nouns and verbs for lexical decision. These tasks activated an extensive network of brain areas, mostly in the left frontal and temporal cortex, which represents the neural correlate of single word processing. Some left hemispheric areas, including the dorsolateral frontal and lateral temporal cortex, were activated only by verbs, while there were no brain areas more active in response to nouns. Furthermore, the comparison of abstract and concrete words indicated that abstract word processing was associated with selective activations (right temporal pole and amygdala, bilateral inferior frontal cortex), while no brain areas were more active in response to concrete words. There were no significant interaction effects between word class and concreteness. Taken together, these findings are compatible with the view that lexical-semantic processing of words is mediated by an extensive, predominantly left hemispheric network of brain structures. Additional brain activations appear to be related to specific semantic content, or, in the case of verbs, may be associated with the automatic access of syntactic information.

Adult↗
PubMed1998

Recovery of neglect after right hemispheric damage: H2(15)O positron emission tomographic activation study.

BACKGROUND: The neural correlates of recovery of unilateral neglect (ULN), as well as of other consequences of focal brain damage, are largely unknown. Functional neuroimaging methods (in particular, positron emission tomography [PET]) can be applied to the in vivo study of recovery mechanisms in neurologic patients. OBJECTIVE: To evaluate the functional cerebral correlates of recovery from ULN in patients with right-sided lesions, with the use of a PET activation paradigm. METHODS: Study of 3 patients with cerebrovascular lesions that involved corticosubcortical (patient 1) or subcortical (patients 2 and 3) areas of the right hemisphere. Unilateral neglect was tested twice, before and after completion of a 2-month rehabilitation program, after which all 3 patients showed considerable improvement. Similarly, 2 PET examinations were performed, before and after recovery, during the performance of a visuospatial task requiring the patients to detect and respond to visual targets moving on a computer screen from the right to the left visual hemifield (experimental condition). The cerebral activation was compared with a baseline task in which subjects responded to a black dot flashing in a fixed position of the right hemifield. RESULTS: The brain areas activated by the performance of the visuospatial task before and after recovery were compared. In all 3 patients, the regions notably more active after recovery were almost exclusively found in right-sided cortical areas and largely overlapped with those observed in a group of 4 normal subjects performing the same task. Other areas, which have been shown to be involved in attentional and oculomotor tasks in other PET studies, were also activated in patients with ULN. CONCLUSIONS: The behavioral recovery of ULN in these patients with predominantly subcortical lesions is mainly associated with cerebral activations in cortical regions similar to those observed in normal subjects. There is some evidence of functional reorganization in individual subjects, which involves other areas related to space representation and exploration.

Aged↗
PubMed1998

The effects of semantic category and knowledge type on lexical-semantic access: a PET study.

Neuropsychological studies of patients with category-specific recognition disorders, as well as PET investigations of semantic category effects in visual recognition tasks, have led some authors to the hypothesis that visual-perceptual knowledge plays a crucial role in the recognition of natural items, such as animals, while functional-associative information is more important for the recognition of man-made tools. To study the cerebral correlates of the retrieval of different types of semantic knowledge about living and nonliving entities, we performed a PET experiment in which normal subjects were required to access visual- and functional-associative information related to visually presented words corresponding to animals and tools. The experimental conditions were the following: (1) Rest. (2) Baseline: letter detection in pseudo-words. (3) Animal, visual knowledge: decide whether the animal has a long or short tail with respect to the body. (4) Animal, associative knowledge: decide whether the animal is typically found in Italy. (5) Tool, visual knowledge: decide whether the object is longer than wider or vice versa. (6) Tool, functional knowledge: decide whether the object is typically used as a kitchen tool. Lexical-semantic access (all lexical conditions pooled) activated the prefrontal cortex on the left and the parietal-occipital junction and posterior cingulate cortex bilaterally. An analysis of the individual experimental conditions in comparison with the nonword baseline showed that accessing visual versus associative knowledge was associated with different activation patterns: predominantly frontal in the case of visual features, temporoparietal for associative knowledge. While the activation patterns involved similar areas for living and nonliving entities, in the case of the latter they were restricted to the left hemisphere. The analysis of main effects confirmed these findings: there were several significant differences in the visual-associative comparison, while category-related differences were less prominent. These findings indicate that the retrieval of different types of knowledge is associated with distinct patterns of brain activation; on the other hand, category-related differences were less evident than in picture matching and naming tasks.

Adult↗
PubMed1998

Visual and spatial perception in the early phase of Alzheimer's disease.

A battery of visuospatial perception tests was administered to 27 mild probable Alzheimer's disease (AD) patients; 21 were reassessed after 8 months. At the first evaluation, AD patients were impaired only in an object-naming task. After 8 months, the performance in the subtests of object perception was unchanged, while there was a significant decline in the total score of the items tapping space perception. A significant worsening was also observed in the Rey's figure copy score and was correlated with the decrease in the spatial perception score. This study confirms that an impairment in visual perceptual tests requiring access to semantic and lexical knowledge is present in the earliest phase of AD, whereas visuospatial and constructional impairments became evident only later. This pattern of progression may represent the clinical correlate of increasing pathological involvement of posterior associative cortex.

Aged↗
PubMed1998

The bilingual brain. Proficiency and age of acquisition of the second language.

Functional imaging methods show differences in the pattern of cerebral activation associated with the subject's native language (L1) compared with a second language (L2). In a recent PET investigation on bilingualism we showed that auditory processing of stories in L1 (Italian) engages the temporal lobes and temporoparietal cortex more extensively than L2 (English). However, in that study the Italian subjects learned L2 late and attained a fair, but not an excellent command of this language (low proficiency, late acquisition bilinguals). Thus, the different patterns of activation could be ascribed either to age of acquisition or to proficiency level. In the current study we use a similar paradigm to evaluate the effect of early and late acquisition of L2 in highly proficient bilinguals. We studied a group of Italian-English bilinguals who acquired L2 after the age of 10 years (high proficiency, late acquisition bilinguals) and a group of Spanish-Catalan bilinguals who acquired L2 before the age of 4 years (high proficiency, early acquisition bilinguals). The differing cortical responses we had observed when low proficiency volunteers listened to stories in L1 and L2 were not found in either of the high proficiency groups in this study. Several brain areas, similar to those observed for L1 in low proficiency bilinguals, were activated by L2. These findings suggest that, at least for pairs of L1 and L2 languages that are fairly close, attained proficiency is more important than age of acquisition as a determinant of the cortical representation of L2.

Adult↗
PubMed1998

The neural systems sustaining face and proper-name processing.

This PET study has revealed the neural system involved in implicit face, proper-name and object name processing during an explicit visual 'same' versus 'different' matching task. Within the identified system, some areas were equally active irrespective of modality (faces or names) or type of stimuli (famous and non-famous) while other areas exhibited differential effects. Our findings support the hypothesis that faces and names involve differential pre-semantic processing prior to accessing a common neural system of stored knowledge of personal identity which overlaps with the one associated with object knowledge. The areas specialized for the perceptual analysis of faces (irrespective of whether they are famous or non-famous) are the right lingual and bilateral fusiform gyri, while the areas specialized for famous stimuli (irrespective of whether they are faces or names) spread from the left anterior temporal to the left temporoparietal regions. One specific area, the more lateral portion of the left anterior middle temporal gyrus, showed increased activation for famous faces relative to famous proper names and for famous proper names relative to common names. The differential responsiveness of this region when processing familiar people suggests functional segregation of either personal attributes or, more likely, the demands placed on processes that retrieve stored knowledge when stimuli have highly similar visual features but unique semantic associations.

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