Biomedical subjects

C Caltagirone

Publications and source records attributed to C Caltagirone.

At least 91 records · Page 5Linked to original sources

PubMed1998

Memory performances in young, elderly, and very old healthy individuals versus patients with Alzheimer's disease: evidence for discontinuity between normal and pathological aging.

In this study we compared memory performances of 29 probable patients with AD (17 mildly and 12 moderately demented) with those of 39 healthy young subjects, 36 elderly subjects (matched with the AD group for age and years of schooling), and 19 healthy very old subjects. In most of the memory tasks used in the present study, a progressive decline in performance was observed passing from the Young to the Elderly to the Very Old to the AD group. However, patients with AD were selectively impaired in the backward reproduction of verbal and spatial span sequences and in the semantic encoding of verbal material. These data are consistent with the hypothesis of not only quantitative but also a qualitative discontinuity between the process of normal aging and the dementia syndrome.

Adult↗

PubMed1998

Cerebral hemodynamic patterns during stimuli tasks in multi-infarct and Alzheimer types of dementia.

OBJECTIVES: To examine differences in cerebrovascular reactivity between multi-infarct and Alzheimer types of dementia. PATIENTS AND METHODS: Using transcranial Doppler, measurements of flow velocity in the middle cerebral arteries during apnea, thumb-to-finger opposition and verbal and design discrimination tasks were recorded in patients with multi-infarct (n=10; mean age 68+/-7.5 years) and Alzheimer types of dementia (n=10; mean age 62+/-9.1 years). Controls were 20 healthy subjects matched for age and sex. RESULTS: Cerebral reactivity to apnea was significantly lower (P<0.0001) in the multi-infarct group compared to the other 2 groups. During the motor task, a nearly selective increase of mean flow velocity in the middle cerebral artery contralateral to the hand performing the task occurred in both controls and Alzheimer patients. A bilateral increase, without side-to-side differences, of flow velocity during movement of each hand was observed in multi-infarct patients. With respect to baseline values, the cognitive tasks produced significant and distinct effects on the left and right side in the controls but not in the patients. Controls showed a significant increase of left middle cerebral artery mean flow velocity during a verbal task (P<0.0001), and of the right middle cerebral artery mean flow velocity during a design discrimination task (P<0.001) when side-to-side comparisons were done. Differently, a bilateral and comparable increase of flow velocity was observed in all patients during performance of the same cognitive tasks. CONCLUSION: These data suggest that cerebrovascular reactivity to apnea could be an additional criterion for discriminating between MID and DAT patients. Transcranial Doppler assessment during cognitive and motor tasks could provide useful complementary information for comprehension changes in cerebral activity in patients with dementia.

Aged↗

PubMed1998

Age and sex differences in cerebral hemodynamics: a transcranial Doppler study.

BACKGROUND AND PURPOSE: Hemodynamic factors seem to play an important role in the pathogenesis of cerebral ischemic events. The aim of this study was to evaluate whether changes in cerebrovascular reactivity occur in women after menopause. METHODS: Using transcranial Doppler ultrasonography, we studied the changes of flow velocity after hypercapnia in the middle cerebral arteries of 45 healthy premenopausal women (mean age, 32.3 years; range, 20 to 47 years) and 40 postmenopausal women (mean age, 54.4 years; range, 48 to 64 years). The same measurements were recorded in two groups of healthy male subjects age matched with premenopausal (45 subjects) and postmenopausal women (40 subjects). Moreover, a subgroup of postmenopausal women aged 48 to 53 years (15 subjects) were compared with a group of 15 premenopausal women of the same age. We obtained hypercapnia with breath holding and evaluated cerebrovascular reactivity with the breath-holding index (BHI). RESULTS: BHI was significantly lower in postmenopausal women (0.89+/-0.3) than in premenopausal women (1.59+/-0.3; P<0.0001) and in young (1.34+/-0.5; P<0.001) and old men (1.20+/-0.4; P<0.04). In the latter group, BHI was significantly lower than in premenopausal women (P<.0001). BHI values were also significantly lower in postmenopausal than in premenopausal women of the same age (0.81+/-0.1 versus 1.34+/-0.1; P<0.0001). CONCLUSIONS: These findings suggest that the large reduction of cerebrovascular reactivity in postmenopausal women cannot be considered a simple factor related to aging but is probably influenced by hormonal changes. The alteration in cerebrovascular regulation could be involved in the increase of cerebrovascular disease in postmenopausal women.

Adult↗

PubMed1998

Correlations of flow velocity changes during mental activity and recovery from aphasia in ischemic stroke.

Mean flow velocity in the middle cerebral arteries (MCAs) during a rest period and during execution of a word-fluency task were measured by means of bilateral transcranial Doppler ultrasonography in 26 stroke patients with Broca's aphasia and in 25 healthy controls. Changes in flow velocity were calculated as percentage of increase from rest to mental activity. In patients, the evaluation was made within 21 days from onset of symptoms and after 2 months of speech therapy, when they were classified into two groups on the basis of extent of recovery from aphasia: absent or slight recovery (group 1, 10 patients) and good recovery (group 2, 16 patients). During the word-fluency task in the first evaluation, the increase in flow velocity in the left MCA was similar in controls and in group 2 patients. In both groups the increase was higher than in group 1 patients (p < 0.0001). Changes in mean flow velocity on the right side were slight and comparable in the three groups of study subjects. After speech therapy, group 1 patients showed a hemodynamic pattern on both sides similar to that observed in the first examination. In group 2 patients, comparison between values of the first and second evaluations showed that the increase of flow velocity in the left MCA was similar. On the right side, the increase was higher in the second than in the first examination (p < 0.01). These data further support the involvement of cerebral areas contralateral to the lesion in functional recovery after stroke. Moreover, the presence of an activation of areas in the lesioned hemisphere, soon after stroke onset, seems to be a predictor of recovery from aphasia.

Aged↗

PubMed1997

Forgetting from long-term memory in severe closed-head injury patients: effect of retrieval conditions and semantic organization.

This study was aimed at investigating long-term forgetting in chronic survivors of severe closed-head injury (CHI). For this purpose, performance decay passing from a 30-sec- to a 60-min-delay test in four memory procedures (Free Recall of unrelated stimuli, Free Recall of related stimuli. Cued Recall and y/n Recognition) of 20 CHI and 20 normal controls was analyzed. Comparable 30-sec-delay performance in CHI and control patients were obtained by manipulating exposure times to study material during the learning phase. Results demonstrated accelerated forgetting in CHI patients in the Free Recall of the related list only. This finding was particularly evident in CHI patients suffering from a focal temporal lobe lesion. These data are discussed in light of retrieval and encoding deficits characterizing memory disorders in CHI patients.

Adolescent↗

PubMed1997

Word-list forgetting in young and elderly subjects: evidence for age-related decline in transferring information from transitory to permanent memory condition.

This study aimed at investigating different memory components involved in word list forgetting by young and elderly healthy individuals. For this purpose, we analyzed in 55 young (age range 20-35) and 50 aged (age range 60-80) healthy subjects the memory decay passing from the fifth immediate to the delayed recall trial of the Rey's Auditory Learning task as a function of the position of the words in the list. Young and elderly groups displayed the same forgetting rate for words recalled from the primacy and mid-list tracts of the serial position curve. However, memory loss for the recency positions was disproportionately larger in the elderly than in the young group. These data demonstrate that aged subjects rely on short-lived memory processes in immediate recall of terminal list items more extensively than young subjects and, as a consequence, a larger proportion of words become inaccessible to them following a delay.

Adult↗

PubMed1997

Transcranial doppler assessment of cerebral flow velocity during perception and recognition of melodies.

The role of each cerebral hemisphere in the perception and recognition of musical information is not yet well understood. We studied cerebral blood flow changes during a melody perception task and a melody recognition task. Blood flow velocity in the two middle cerebral arteries of twenty right-handed musically naif volunteers were simultaneously measured by means of bilateral transcranial Doppler ultrasonography during two minutes of passive melody listening and two minutes of a melody recognition task. With respect to baseline values, a bilateral increase of flow velocity occurred in the middle cerebral arteries with a non-significant trend for the right artery during the melody perception task. During the melody recognition task, a significant increase in flow velocity was recorded on the right side with respect to the left side, where a slight simultaneous decrease was found. Our data suggest that melody perception requires bilateral activation of hemispheres and melody recognition mainly an activation of the right hemisphere. This study confirms the ability of transcranial Doppler ultrasonography to correlate artery flow dynamics with selective cerebral activation.

Adult↗

PubMed1997

A callosal disconnection syndrome of vascular origin.

OBJECTIVE: To study the after-effects of a selective lesion of the corpus callosum on the capacity in transferring spatial information on arm posture derived from kinesthesia and vision. DESIGN: Neuropsychological and psychophysical evaluations of a patient with callosal damage. SETTING: Institute of Neurology, University of "Tor Vergata", Rome, Italy and Research Centre, IRCCS "S. Lucia", Rome, Italy. PATIENT: P.V., a 59 years old man suffering from a vascular lesion of the left half of corpus callosum and left callosal radiations. MEASURES: Sensori-motor and cognitive tasks. Exo- and egocentric pointing abilities tasks. RESULTS: Impairments due to a disconnection between the two cerebral hemispheres were pointed out. About pointing abilities, errors were greater when each hand pointed to the remembered location of the other hand. Errors decreased dramatically with eyes open for right hand pointing to remembered location of left and right hand, and left hand pointing to remembered location of left hand. Open eyes left hand pointing to remembered location of right hand remained as poor as with eyes closed. CONCLUSIONS: The results appear compatible with the following network: visual information from striate and extrastriate cortex is passed forward to parietal cortex bilaterally (even in PV due to the splenium sparing). Kinesthetic information from parietal cortex of left and right hemisphere converge on a single visuokinesthetic center, lateralized to the left hemisphere. Information about limb position in three-dimensional space is then encoded in body-centered coordinates and passed forward to motor and premotor cortex in the frontal lobe. These frontal regions are those disconnected in PV.

Brain Ischemia↗

PubMed1996

Recency effect in anterograde amnesia: evidence for distinct memory stores underlying enhanced retrieval of terminal items in immediate and delayed recall paradigms.

This study was devised to investigate immediate and delayed recency effects in anterograde amnesic patients. For this purpose, a word-list immediate recall paradigm and a modified version of the procedure devised by Baddeley and Hitch [Attention and Performance, Erlbaum, NJ, 1977] for eliciting the recency effect in delayed recall conditions was administered to a sample of amnesic patients and to a group of age-matched healthy subjects. Amnesics disclosed a fully normal recency effect in the immediate recall paradigm and a deficient recency effect in the delayed recall condition. These data, taken together with experimental evidence from a patient affected by a pure form of phonological short-term memory impairment [35], draw a double neuropsychological dissociation suggesting a differential origin for the two kinds of recency effects: a short-term memory output underlying enhanced recall of terminal items in immediate recall paradigms, and an ordinal retrieval strategy applied to long-term memory stored units at the root of the delayed recency effect.

Adult↗

PubMed1996

Perceptual and conceptual components in implicit and explicit stem completion.

This study was aimed at investigating functional and neuropsychological dissociations between repetition priming and explicit memory tasks. The explicit and implicit versions of the stem completion task were administered to a group of amnesics and a group of control subjects. In Experiment 1 both the explicit and implicit stem completions were significantly higher when the same presentation modality was used for studying and testing than when a change in modality from studying to testing occurred. Amnesics had normal implicit and deficient explicit completion performance. Experiment 2 revealed an advantage of the semantic over the phonological condition only in the explicit task and only in control subjects. Amnesic patients completed the same percentage of words as normal subjects in the phonological and semantic conditions of the implicit task and in the phonological condition of the explicit task but were deficient in intentionally completing semantically processed words. Possible interpretations of these results are discussed according to theoretical models that distinguish memory tasks along an explicit-implicit dichotomy (multiple memory system theory) or along a perceptual-conceptual dichotomy (transfer-appropriate procedures approach), and alternative theoretical positions are evaluated regarding repetition priming and memory deficits in amnesic patients.

Adult↗

PubMed1996

Recency effect in Alzheimer's disease: a reappraisal.

This study investigated the hypothesis that discrepant results regarding the recency effect in Alzheimer's disease (AD) patients are due to the different scoring procedures used by various authors and/or to the different number of terminal items attributed to the recency part of the curve. Our results indicate that the last two processed words are available to AD patients for recall, just as they are to controls. Words processed slightly earlier are less available to AD patients than to controls, presumably because of the accelerated forgetting rate in demented patients.

Aged↗

PubMed1996

Bilateral simultaneous transcranial Doppler monitoring of flow velocity changes during visuospatial and verbal working memory tasks.

Twenty-two normal volunteers were studied by simultaneous bilateral transcranial Doppler (TCD) monitoring of flow velocity changes in the middle cerebral arteries during visuospatial and verbal working memory tasks. All tasks were visually presented material; they required full engagement of subjects during the study, similar attention demands and a manual response when the appropriate target was recognized. Stimuli were presented tachistoscopically. Each task produced significant and distinct effects on flow velocity with respect to baseline values. When side-to-side comparisons were performed, a significantly higher increase in flow velocity was observed in the right middle cerebral artery (MCA) compared with the left one during the visuospatial task (P < 0.005). Our findings agree with results of recent studies using PET which show lateralized activation during working memory tasks. The high temporal resolution of this technique suggests that further application in cerebral flow change monitoring during neuropsychological studies could be promising.

Adult↗

PubMed1996

Implicit memory in parkinsonian patients: evidence for deficient skill learning.

The aim of this study was to investigate procedural learning in idiopathic Parkinson's disease (PD) patients. For this purpose, 18 nondemented PD patients and 20 age-matched healthy subjects were trained to learn a visuoperceptual skill (mirror reading) and a cognitive skill with a motor demand (puzzle assembly task). In 3-day sessions, the patients were requested to perform with repeated and unrepeated stimuli, in order to distinguish between pure procedural learning and skill learning at least partially supported by explicit memory retrieval. In the mirror reading task, the PD patients showed normal improvement in reading times for repeated words but no improvement at all for unrepeated stimuli. In the puzzle assembly task, PD patients did not show any significant learning either for repeated or unrepeated stimuli. These results, which document deficient learning of procedures in parkinsonians, are discussed in the light of conflicting data reported regarding implicit memory in PD.

Aged↗

PubMed1996

The Mental Deterioration Battery: normative data, diagnostic reliability and qualitative analyses of cognitive impairment. The Group for the Standardization of the Mental Deterioration Battery.

This study aimed at investigating the clinical usefulness of the Mental Deterioration Battery (MDB) in the neuropsychological diagnosis and characterization of the dementia syndrome. In this paper, we report: (a) normative data for various test scores derived from the analysis of performance of 340 normal subjects living in urban areas; (b) an evaluation of the reliability of the single tests and of the battery as a whole in differentiating normal subjects from patients affected by cognitive deterioration derived from the analysis of performance of 130 normal subjects living in rural areas and 134 patients affected by probable Alzheimer's dementia; (c) a cluster analysis of performances of the 340 normal subjects in the standardization group to evaluate possible criteria of homogeneity according to which the various MDB scores tend to aggregate; (d) an analysis of performance profiles of 183 patients with right monohemispheric focal lesions, 159 patients with left unilateral lesions with aphasia and 131 left-lesioned nonaphasic patients to evaluate the specificity of the single tests of the battery in documenting a selective impairment of one of the two cerebral hemispheres. Results confirm the reliability of the MBD in discriminating between normal and demented patients and provide indications for use of the battery in differentiating qualitative patterns of cognitive impairment.

Adult↗

PubMed1996

Transcranial Doppler assessment of cerebrovascular reactivity in symptomatic and asymptomatic severe carotid stenosis.

BACKGROUND AND PURPOSE: Some studies have suggested a link between impaired cerebral hemodynamics and stroke in patients with carotid stenosis. The aim of this study was to assess the effects of severe carotid stenosis on cerebrovascular reactivity and the possible changes after endarterectomy. METHODS: Using bilateral transcranial Doppler ultrasound, we studied the changes of flow velocity after hypercapnia in the middle cerebral arteries of 10 control subjects and 24 patients (13 symptomatic and 11 asymptomatic) with unilateral severe carotid stenosis before and after endarterectomy. Cerebrovascular reactivity was evaluated with the breath-holding index (BHI). RESULTS: Before endarterectomy, BHI (mean value +/- SD) was significantly lower (P < .001) in the stenotic side of symptomatic patients (0.40 +/- 0.2) than in control subjects (1.12 +/- 0.3), the stenotic side of asymptomatic patients (0.80 +/- 0.4), and the normal side of both symptomatic (0.93 +/- 0.3) and asymptomatic ultrasonics (1.03 +/- 0.2) patients. On the other hand, no significant difference in BHI was detected in control subjects, on the normal side of symptomatic and asymptomatic patients, and the stenotic side of asymptomatic patients. After endarterectomy, BHI significantly increased (P < .0001) on the stenotic side of symptomatic patients (1.06 +/- 0.2) while remaining substantially stable on the normal side of both symptomatic and asymptomatic patients and on the stenotic side of asymptomatic patients. CONCLUSIONS: These findings suggest that the study of cerebrovascular reactivity to hypercapnia may be relevant in evaluating the functional effects of carotid stenosis. Further investigations are needed to confirm the reliability of the breath-holding method in the selection of patients who might benefit most from carotid endarterectomy.

Aged↗

PubMed1995

Different components in word-list forgetting of pure amnesics, degenerative demented and healthy subjects.

This study investigated the contribution of different components of the serial position curve to the accelerated forgetting rate displayed by amnesic and degenerative demented patients in word-list recall. For this purpose, we analyzed immediate and 15 min delayed recall performances on Rey's 15-word learning task of 16 pure amnesic, 15 Alzheimer's demented and 81 healthy subjects. Results documented that in all groups most forgetting occurred at the expense of terminal items of the word list. Nevertheless, both amnesic and demented patients showed a disproportionately larger memory loss on the recent part of the serial position curve than healthy subjects. Finally, amnesics (but not AD patients) suffered from a significantly larger forgetting rate for primacy items than normal controls. These data demonstrate that a critical deficit in memory disordered patients is represented by a failure in transferring information from a transitory memory status to a more durable storing condition. At least in amnesic patients, our results also suggest "true" long-term forgetting, presumably due to decay or to the intervening inaccessibility of previously stored memory representations.

Adult↗

PubMed1995

Forgetting from long-term memory in dementia and pure amnesia: role of task, delay of assessment and aetiology of cerebral damage.

This study investigated the hypothesis that memory disordered patients suffer of an exalted forgetting rate from long-term memory within the first few minutes following acquisition. For this purpose, we administered to groups of Alzheimer's (AD), Multi-infarct demented (MID), pure amnesic and age-matched normal controls a test involving immediate and 15-min delayed word-list recall and a modified version of the Huppert and Piercy's procedure (1978) assessing yes/no Recognition for pictures at 90 sec, 10 min, 1 hr and 24 hr delay intervals. Results showed an abnormal immediate/delayed performance decline for the word-list recall in AD and pure amnesic patients. In the same period, however, their Recognition score in the Huppert and Piercy's procedure decayed at normal rate. In the following intervals (1 hr and 24 hr), both groups disclosed abnormal forgetting slopes. Vascular demented patients, by contrast, disclosed fully normal forgetting rates both on the word-list recall and on the Huppert and Piercy's procedure. These findings are discussed in the light of cognitive mechanisms and neuroanatomical structures presumably underlying memory consolidation.

Adolescent↗

PubMed1995

Components in the visual processing of known and unknown faces.

This study investigated the neural basis and cognitive mechanisms of disorders affecting the visual processing of human faces. Two patients affected by prosopagnosia (PA), 45 unilateral brain-damaged patients not previously selected for gnosic disturbance, and 52 normal subjects were administered three tasks involving visual matching of unfamiliar faces, identification of famous faces, and age attribution to unknown faces. Results confirmed that the right hemisphere (and particularly the posterior region) is critical for all of the main aspects of facial processing. Neuroradiological and PET examination in both PA patients revealed a lesion in the territory of the right posterior cerebral artery (infero-mesial areas of temporal and occipital lobes). Moreover, group comparisons showed that patients affected by a right posterior lesion obtained the worst scores on all tasks of our battery. Both group comparisons and single-case analyses pointed out that a deficient recognition of familiar faces is generally independent of perceptual disorders and, as such, should be considered mnestic in nature. Disorders in the age attribution, on the contrary, appear to be strictly associated with deficits in the perceptual analysis of unfamiliar faces.

Aged↗