Search PubMed⌕ Search

Biomedical subjects

G A Carlesimo

Publications and source records attributed to G A Carlesimo.

At least 19 recordsLinked to original sources
PubMed2006

Verbal short-term memory in individuals with congenital articulatory disorders: new empirical data and review of the literature.

BACKGROUND: To investigate the nature of the articulatory rehearsal mechanism of the Articulatory Loop in Baddeley's Working Memory model, it seems particularly important to study individuals who developed a deficit (dysarthria) or total abolition (anarthria) of the ability to articulate language following a cerebral lesion. METHOD: In this study, a forced-choice recognition procedure for word sequences of increasing length was used to evaluate verbal short-term memory in nine individuals with severe congenital motor and verbal disabilities (seven anarthric and two severely dysarthric) and associated intellectual disability (ID) and 30 normal children of comparable mental age. RESULTS: The normal children exhibited classical phonological similarity effects (better performance on acoustically dissimilar than on similar word lists), word length (greater accuracy on two-syllable than on four-syllable word lists) and frequency of occurrence (an advantage of high-frequency over low-frequency words). Instead, all of these effects were lacking in the experimental group. CONCLUSIONS: These data suggest that persons with congenital anarthria/dysarthria and ID present defective maturation at many levels of the Articulatory Loop and reduced contribution of semantic-lexical processing in the temporary retention of phonological sequences. It is likely that in these individuals both communicative deficits and ID play a role in the impaired development of verbal short-term memory abilities.

Adolescent↗
PubMed2006

Alexithymia in Parkinson's disease is related to severity of depressive symptoms.

The authors investigated the possible relationship between depression and alexithymia in a population of hospitalized patients suffering from Parkinson's disease (PD). Fifty-eight PD patients without dementia participated in the study. Alexithymia was screened using the 20 item version of the Toronto Alexithymia Scale (TAS 20). Depression was diagnosed using a Structured Clinical Interview (SCID I) for DSM-IV. Severity of depression was evaluated with the Beck Depression Inventory (BDI). The prevalence of Alexithymia was about 21%. PD patients with major depression were significantly more alexithymic (TAS 20 average score = 61.4) than PD patients without depression (TAS 20 average score = 47.4) and, also, tended to be more alexithymic than PD patients with minor depression (MiD; TAS 20 average score =50.6), whereas no difference was found between PD patients with MiD and PD patients without depression. Moreover, high scores obtained on the BDI were found to strongly predict high level of alexithymia in these patients. These results extend to a cohort of PD patients previous data from the literature evidencing a strong association between alexithymia and severity of depressive symptoms.

Affective Symptoms↗
PubMed2006

Major and minor depression in Parkinson's disease: a neuropsychological investigation.

Previous studies have failed to distinguish the differential contribution of major and minor depression to cognitive impairment in patients with idiopathic Parkinson's disease (PD). This study was aimed at investigating the relationships among major depression (MD), minor depression (MiD) and neuropsychological deficits in PD. Eighty-three patients suffering from PD participated in the study. MD and MiD were diagnosed by means of a structured interview (SCID-I) based on the DSM-IV criteria, and severity of depression was evaluated by the Beck Depression Inventory. For the neuropsychological assessment, we used standardized scales that measure verbal and visual episodic memory, working memory, executive functions, abstract reasoning and visual-spatial and language abilities. MD patients performed worse than PD patients without depression on two long-term verbal episodic memory tasks, on an abstract reasoning task and on three measures of executive functioning. The MiD patients' performances on the same tests fell between those of the other two groups of PD patients but did not show significant differences. Our results indicate that MD in PD is associated with a qualitatively specific neuropsychological profile that may be related to an alteration of prefrontal and limbic cortical areas. Moreover, the same data suggest that in these patients MiD and MD may represent a gradual continuum associated with increasing cognitive deficits.

Aged↗
PubMed2005

Integration of cognitive allocentric information in visuospatial short-term memory through the hippocampus.

Visuospatial short-term memory relies on a widely distributed neocortical network: some areas support the encoding process of the visually acquired spatial information, whereas other ares are more involved in the active maintenance of the encoded information. Recently, in a pointing to remembered targets task, it has been shown in healthy subjects that, for memory delays of 5 s, spatial errors are affected also by cognitive allocentric information, i.e., covert spatial information derived from a pure mental representation. We tested the effect of a lesion of the hippocampus on the accuracy of pointing movements toward remembered targets, with memory delays falling in the 0.5-30 s range. The spatial distributions of the two target sets we used (line and left-right) allowed the exploitation of cognitive allocentric spatial information: both sets were in the frontal plane, the line one being composed by eleven points distributed uniformly along a virtual line tilted 45 degrees away from the vertical, whereas the left-right set was composed by two workspaces symmetrically distributed at the extremes of a horizontal virtual line. We have found a significant difference between the performance of three hippocampal amnesic subjects and a group of normal controls for delays equal to or longer than 15 s, the difference being along the allocentric axis, i.e., the direction of the virtual line defined by the target set. On this basis we suggest that the hippocampal formation may enhance the spatial information processed within short-term memory with cognitive allocentric information. The association that may be operated through the neocortical-hippocampal loop of the newly acquired spatial information with well established spatial cognitive items could affect the precision of the short-term memory storage for memory delays exceeding about 15 s and might be the result of a modulation of the span of the spatial memory buffer along context-specific directions.

Adult↗
PubMed2005

Priming for novel between-word associations in patients with organic amnesia.

Ten amnesic patients of various etiologies and 10 matched normal controls participated in this study. On 2 consecutive days, subjects studied 30 novel word-word associations 6 times. Using a cued recall task, we assessed episodic learning and delayed retention of the study material immediately after each study phase and again 24 hr after the final study phase. Further, we evaluated implicit memory for new between-word associations by means of an automatic relational priming paradigm immediately after the delayed cued recall trial. Amnesic patients performed poorly on the cued recall task. Moreover, in the overall group of amnesics the priming effect failed to reach statistical significance. When the overall group of amnesics was split according to mean performance on the cued recall task, those in the low performer subgroup--comprised of 6 patients with direct or indirect involvement of the hippocampi--were particularly poor at episodically remembering the associations and did not reveal any relational priming. These data support the hypothesis of similar impairment of new episodic and implicit learning in amnesic patients and suggest that the hippocampus is crucial for both kinds of new learning.

Adult↗
PubMed2005

Characterization of memory profile in subjects with amnestic mild cognitive impairment.

Different aspects of episodic long-term, short-term and implicit long-term memory were investigated in subjects who strictly fulfilled the criteria for the amnestic form of Mild Cognitive Impairment (a-MCI). Results showed normal short-term memory abilities in these subjects, while each of the episodic long-term memory indices explored showed poorer results in a-MCI subjects with respect to normal controls. Although some episodic memory functions were relatively well preserved, others appeared to have deteriorated to a level comparable to that of mild AD patients. The finding of an extensive impairment of all memory functions depending on hippocampal structures in a population with a high risk of developing dementia is strongly supportive of the hypothesis that a pure amnesic syndrome characterizes the preclinical phase of AD.

Activities of Daily Living↗
PubMed2004

Clinical predictors and neuropsychological outcome in severe traumatic brain injury patients.

BACKGROUND: The aim of the study was to evaluate the possible significant role of some clinical factors in predicting cognitive outcome in a group of severe traumatic brain injury (TBI) patients, with Glasgow Coma Scale (GCS) lower than 8 and duration of unconsciousness for at least 15 days (prolonged coma). METHOD: A consecutive sample of 25 survivors of severe TBI attending the Physical and Cognitive Rehabilitation program participated in this study. The neuropsychological test battery included: Word-list Learning, Prose recall, Rey Figure Delayed recall, Word fluency, Raven's Progressive Matrices' 47. The clinical variables evaluated in correlation with the neuropsychological outcome were the following: age, duration of unconsciousness, duration of post-traumatic amnesia, interval from head trauma to neuropsychological evaluation, interval from head trauma to recovery of oral feeding, and finally interval from head trauma to first verbal communication. FINDINGS: The clinical variable with a significant predictive value on most neuropsychological scores was the interval from head trauma to the recovery of oral feeding. CONCLUSIONS: If this result is confirmed in larger samples, time interval of oral feeding recovery from head trauma should be considered as a possible predictor of neuropsychological outcome in TBI patients with prolonged coma.

Adolescent↗
PubMed2004

Brain activity during intra- and cross-modal priming: new empirical data and review of the literature.

A positron emission tomography (PET) study was conducted to investigate the neurofunctional correlate of auditory within-modality and auditory-to-visual cross-modality stem completion priming. Compared to the auditory-to-auditory priming condition, cross-modality priming was associated with a significantly larger regional cerebral blood flow (rCBF) decrease at the boundary between left inferior temporal and fusiform gyri, brain regions previously associated with modality independent lexical retrieval and reading. Instead, within-modality auditory priming was associated with a bilateral pattern of prefrontal rCBF increase. This was likely the expression of more efficient access to output lexical representations and involuntary retrieval of the recent episode during which the just generated word had been encountered.

Acoustic Stimulation↗
PubMed2004

Verbal short-term memory in Down's syndrome: an articulatory loop deficit?

BACKGROUND: Verbal short-term memory, as measured by digit or word span, is generally impaired in individuals with Down's syndrome (DS) compared to mental age-matched controls. Moving from the working memory model, the present authors investigated the hypothesis that impairment in some of the articulatory loop sub-components is at the base of the deficient maintenance and recall of phonological representations in individuals with DS. METHODS: Two experiments were carried out in a group of adolescents with DS and in typically developing children matched for mental age. In the first experiment, the authors explored the reliance of these subjects on the subvocal rehearsal mechanism during a word-span task and the effects produced by varying the frequency of occurrence of the words on the extension of the word span. In the second experiment, they investigated the functioning of the phonological store component of the articulatory loop in more detail. RESULTS: A reduced verbal span in DS was confirmed. Neither individuals with DS nor controls engaged in spontaneous subvocal rehearsal. Moreover, the data provide little support for defective functioning of the phonological store in DS. CONCLUSIONS: No evidence was found suggesting that a dysfunction of the articulatory loop and lexical-semantic competence significantly contributed to verbal span reduction in subjects with DS. Alternative explanations of defective verbal short-term memory in DS, such as a central executive system impairment, must be considered.

Adolescent↗
PubMed2004

Gross morphology and morphometric sequelae in the hippocampus, fornix, and corpus callosum of patients with severe non-missile traumatic brain injury without macroscopically detectable lesions: a T1 weighted MRI study.

OBJECTIVE: The gross morphology and morphometry of the hippocampus, fornix, and corpus callosum in patients with severe non-missile traumatic brain injury (nmTBI) without obvious neuroradiological lesions was examined and the volumes of these structures were correlated with performance on memory tests. In addition, the predictability of the length of coma from the selected anatomical volumes was examined. METHOD: High spatial resolution T1 weighted MRI scans of the brain (1 mm3) and neuropsychological evaluations with standardised tests were performed at least 3 months after trauma in 19 patients. RESULTS: In comparison with control subjects matched in terms of gender and age, volume reduction in the hippocampus, fornix, and corpus callosum of the nmTBI patients was quantitatively significant. The length of coma correlated with the volume reduction in the corpus callosum. Immediate free recall of word lists correlated with the volume of the fornix and the corpus callosum. Delayed recall of word lists and immediate recall of the Rey figure both correlated with the volume of the fornix. Delayed recall of the Rey figure correlated with the volume of the fornix and the right hippocampus. CONCLUSION: These findings demonstrate that in severe nmTBI without obvious neuroradiological lesions there is a clear hippocampal, fornix, and callosal volume reduction. The length of coma predicts the callosal volume reduction, which could be considered a marker of the severity of axonal loss. A few memory test scores correlated with the volumes of the selected anatomical structures. This relationship with memory performance may reflect the diffuse nature of the damage, leading to the disruption of neural circuits at multiple levels and the progressive neural degeneration occurring in TBI.

Adult↗
PubMed2003

Loss of spatial learning in a patient with topographical disorientation in new environments.

The case is described of a patient who, following cerebral hypoxia, developed severe difficulty in orienting himself in new environments in the context of a mild global amnesic syndrome. Some episodes he related suggested that his main difficulty was remembering the spatial/directional value of landmarks he recognised. A neuroradiological examination documented severe bilateral atrophy of the hippocampi associated with atrophic changes in the cerebral hemispheres, most marked in the dorsal regions. Neuropsychological and experimental evaluation showed a severe deficit of spatial learning with substantially preserved ability to learn verbal and visual-object information. He was also virtually unable to learn a route in a maze task based exclusively on spatial data, but the availability of visual cues substantially improved his learning. Finally, he performed within normal limits on various tests investigating knowledge acquired premorbidly regarding famous buildings, routes in the town he had been living in since childhood, and geography. Topographical disorientation may be subtended by a specific difficulty in storing the spatial/directional value of visual landmarks in novel environments. The hippocampus appears to be involved in the acquisition of new topographical spatial knowledge.

Adult↗
PubMed2002

Evaluation of communicative and functional abilities in Wolf-Hirshhorn syndrome.

BACKGROUND: Wolf-Hirschhorn syndrome (WHS) is a genetic condition characterized by many clinical disorders, learning difficulties, dysphagia, neuromotor deficits and communicative deficits. Up until now, no studies in the literature have described the development of communicative and functional abilities in subjects with WHS. METHOD: In the present study of 11 patients with WHS, a descriptive analysis was made of several abilities and three groups of patients were identified on the basis of the severity of their functional deficit. RESULTS: A non-homogeneous picture of impairment emerged in various areas of development. Overall, the neuromotor abilities of these patients were more adequate than their abilities related to autonomy in personal life, alimentary function, and cognitive and communicative-linguistic aspects. CONCLUSION: Based on the identification of specific patterns of communicative and functional impairment in subjects with WHS, rehabilitative intervention strategies can be planned to increase their communicative opportunities, and possibilities for active and autonomous participation in various life contexts (e.g. home, school and the social environment).

Abnormalities, Multiple↗
PubMed2001

Remembering what but not where: independence of spatial and visual working memory in the human brain.

We report the neuropsychological and MRI investigation of a patient (MV) who developed a selective impairment of visual-spatial working memory (WM) with preservation not only of verbal, but also of visual shape WM, following an ischemic lesion in the cerebral territory supplied by one of the terminal branches of the right anterior cerebral artery. MV was defective in visual-spatial WM whether the experimental procedure involved arm movement for target pointing or not. Also, in agreement with the role generally assigned to visual-spatial WM in visual imagery, MV was extremely slow in the mental rotation of visually and verbally presented objects. In striking contrast with the WM deficit, MV's visual-spatial long-term memory was intact. The behavioral and neuroanatomical investigation of MV provides support for the hypothesis that the superior frontal gyrus (BA 6) and the dorsomedial cortex of the parietal lobe (BA 7) are part of the neural circuitry underlying visual-spatial WM in humans.

Brain↗
PubMed2001

Procedural learning deficit in children with Williams syndrome.

The present study was aimed at evaluating implicit memory processes in subjects with Williams syndrome (WS) and comparing them to mental-age (MA) matched normal children. For this purpose, tests of verbal and visuo-perceptual explicit memory, verbal and visual repetition priming as well as procedural learning tasks were administered to 12 WS and 12 MA matched subjects. WS subjects showed a level of repetition priming similar to that of MA normal controls. In contrast, WS children showed a reduced learning rate in the two procedural tasks. Although deficient explicit memory and executive dysfunction cannot be excluded from the performance of WS subjects, these results suggest a specific deficit of procedural learning in this particular group of mentally retarded children. This finding is relevant for our knowledge about the qualitative aspects of the anomalous cognitive development in mentally retarded people and the neurobiological substrate underlying this development.

Adolescent↗
PubMed2001

Neuropsychological assessment of patients with severe neuromotor and verbal disabilities.

In people with cerebral palsy, severe neuromotor disability and communication problems make standard neuropsychological tests impossible. Therefore, alternative methods and specific aids must be developed to allow patients to autonomously respond to the examiner's questions. In the present individuals and study, a neuropsychological evaluation was made of a group of eight individuals with cerebral palsy, and severe neuromotor and verbal disabilities, and a group of 19 normal subjects matched for mental age. The tests were administered using an autonomous selection method in which the patient selects the various responses through specific aids without the examiner's interference. Patients' group performances in visuo-spatial and memory tests were on average lower than the mean of the control group. In the verbal domain, patients' scores were comparable to those of normal children in all tests but one assessing the comprehension of syntactically complex sentences. An analysis of the patients' individual performances also revealed heterogeneous cognitive profiles: some patients presented a homogeneously distributed cognitive impairment and others a more selective one. This finding is particularly important for planning differentiated learning programmes, and identifying suitable communicative instruments in rehabilitative and educational settings.

Adolescent↗
PubMed2001

Intact cross-modality text-specific repetition priming in patients with Alzheimer's disease.

This study was aimed at investigating the basic mechanisms of the normal repetition priming evoked by text re-reading procedures in Alzheimer's disease (AD) patients (Monti, Gabrieli, Wilson, & Reminger, 1994; Monti et al., 1997). For this purpose, we contrasted the reading facilitation elicited by previous reading or listening to a text in a sample of AD patients and a group of age-matched normal controls. Consistent with previous evidence in normal undergraduates (Levy & Kirsner, 1989), previous listening to a text decreased the successive reading time of the same text (cross-modality priming). However, the reading facilitation elicited by previous reading of the same text (within-modality priming) was significantly larger than the facilitation evoked by previous listening. Compared to normal controls, AD patients showed intact cross-modality and within-modality priming. These data are discussed in the light of alternative hypotheses regarding the basic mechanisms of impaired and spared repetition priming in degenerative demented patients.

Aged↗
PubMed2001

Parieto-frontal interactions in visual-object and visual-spatial working memory: evidence from transcranial magnetic stimulation.

This study aimed to investigate whether transcranial magnetic stimulation (TMS) can induce selective working memory (WM) deficits of visual-object versus visual-spatial information in normal humans. Thirty-five healthy subjects performed two computerized visual n-back tasks, in which they were required to memorize spatial locations or abstract patterns. In a first series of experiments, unilateral or bilateral TMS was delivered on posterior parietal and middle temporal regions of both hemispheres after various delays during the WM task. Bilateral temporal TMS increased reaction times (RTs) in the visual-object, whereas bilateral parietal TMS selectively increased RTs in the visual-spatial WM task. These effects were evident at a delay of 300 ms. Response accuracy was not affected by bilateral or unilateral TMS of either cortical region. In a second group of experiments, bilateral TMS was applied over the superior frontal gyrus (SFG) or the dorsolateral prefrontal cortex (DLPFC). TMS of the SFG selectively increased RTs in the visual-spatial WM task, whereas TMS of the DLPFC interfered with both WM tasks, in terms of both accuracy and RTs. These effects were evident when TMS was applied after a delay of 600 ms, but not one of 300 ms. These findings confirm the segregation of WM buffers for object and spatial information in the posterior cortical regions. In the frontal cortex, the DLPFC appears to be necessary for WM computations regardless of the stimulus material.

Adult↗