Biomedical subjects

M Sabbadini

Publications and source records attributed to M Sabbadini.

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↗

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↗

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

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↗

PubMed1998

Associative visual agnosia resulting from a disconnection between intact visual memory and semantic systems.

We report the case of a patient (RC) who developed a severe visual agnosia, associated to alexia without agraphia, color anomia and amnesia, following an ischemic stroke in the territory supplied by the left posterior cerebral artery. Based on his proficient performance on tests evaluating analysis of elementary visual features, formation of viewer-centered and object-centered representations of visual stimuli and discrimination between drawings representing real and unreal objects, we concluded that the critical locus of deficit was a disconnection between the normally functioning visual memory store and the semantic system. RC's disturbance in visual processing of human faces paralleled his recognition disorder of other classes of objects. The possible contribution of neurobiological factors in determining RC's agnosic deficit is discussed.

Aged↗

PubMed1998

Retrograde memory deficits in severe closed-head injury patients.

A battery of tests evaluating different aspects of retrograde memory (autobiographical, public events, semantic knowledge) was administered to a group of 20 patients who had suffered from a severe closed-head injury (CHI) and who had recovered from the post-traumatic amnesia period and to a group of sex-, age- and education-matched normal controls. Results document a high prevalence of retrograde memory deficits among CHI individuals. The deficit involves both autobiographical and public events memories and extends to early acquired basic and cultural knowledge. The severity of the deficit does not vary according to some kind of temporal gradient or according to a presumed hierarchical or modality organization of the semantic system. However, in the domain of basic knowledge it more severely affects information pertaining to living than nonliving categories of objects. With the exception of a more severe deficit in retrieving autobiographical events occurred in the last year before trauma in a subgroup of patients with focal lesions restricted to the right hemisphere as compared to left lesioned patients, no clear relationship emerges between severity of the retrograde memory deficit and locus of focal cerebral lesions as demonstrated by neuroradiological exams.

Adolescent↗

PubMed1998

Analysis of the memory impairment in a post-encephalitic patient with focal retrograde amnesia.

This study aimed to characterize the qualitative pattern of focal retrograde memory impairment shown by a post-encephalitic patient (AV). AV's memory deficit encompassed autobiographical data, public events and famous people. In a public events questionnaire, she demonstrated a smooth negative temporal gradient with good recollection of events that occurred about 15 years before the disease but poor memory of more recent events. Her visual input lexicon was unimpaired, as demonstrated by normal lexicality judgment for words and normal familiarity judgment for proper names, but she was poor in familiarity judgment for famous faces (prosopagnosia) and in accessing the meaning of words or specific information about people. The cerebral MRI demonstrated widespread abnormal intensity areas encroaching upon the white matter of temporal, parietal and occipital lobes but sparing temporal poles and orbito-frontal cortex.

Adult↗

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↗

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↗

PubMed1995

Multichannel visual evoked potentials in migraine.

Multichannel recordings of visual evoked potentials (VEPs) have proved to be useful in the evaluation of visual field defects. We studied the topographic distribution of transient VEPs in 15 migraine patients (8 with visual aura and 7 without) and 15 age-matched controls during the migraine-free interval. All the subjects included in the study had normal visual fields. VEPs were recorded from 9 electrodes placed on the posterior scalp. Stimuli were full-field and hemifield reversing square wave grating patterns of medium spatial frequency (4 c/deg). The groups did not show significant differences in latencies and amplitudes of the major components (N70, P100) recorded from the midline. However, migraine patients with visual hemianopic aura showed definite asymmetries in the VEP amplitude distribution. Significantly reduced, absent or polarity-invered VEP responses were recorded ipsilateral to the side of the prodromic visual symptoms. Direct comparison of affected and unaffected hemispheres by partial field stimulation confirmed these findings. According to the VEP cortical generator theory, these abnormalities suggest a functional anomaly consistent with the clinical syndrome and detectable also in the migraine-free interval. None of the migraine patients without aura or the controls showed VEP amplitude asymmetries. We conclude that multichannel VEP recordings may discriminate between different subtypes of migraine and contribute important physiopathological information to the study of this disease.

Adolescent↗

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↗

PubMed1994

Visual repetition priming for words relies on access to the visual input lexicon: evidence from a dyslexic patient.

In this study we tested the hypothesis that visual repetition priming for words depends upon the accessibility of lexical units in the visual input lexicon. For this purpose, we investigated a dyslexic patient, A.M., whose neuropsychological performances suggested an impaired access to the lexical route of reading. According to the predictions, Experiments 1 and 2 demonstrated deficient priming in tests involving the visual presentation of words (Word Identification and Stem Completion). In Experiment 3, we demonstrated that A.M.'s deficient priming was specific for visually presented words, in that the auditory presentation elicited a normal priming effect (auditory Stem Completion). These data are discussed in the light of a theoretical framework suggesting a fractionation of the modalities by which repetition priming can be elicited, each mediated by a particular memory subsystem.

Attention↗

PubMed1993

Effect of carbamazepine on EEG background activity and on interictal epileptiform abnormalities in focal epilepsy.

The effect of carbamazepine (CBZ) on EEG background activity and on interictal epileptiform abnormalities (IEA) was studied in 15 patients with focal epilepsy who started antiepileptic drug treatment (AED) for the first time. A computerized EEG study, performed before and two months after starting therapy, utilized spectral analysis and automatic recognition of IEA. The occurrence of seizures was considered in order to clarify the relationship between IEA and the seizures themselves. Statistical evaluation of EEG spectral values was calculated through analysis of variance (ANOVA), while for IEA the non parametric Wilcoxon test was utilized. In 13 patients who remained seizure-free during the two month-period of observation, IEA was unchanged or decreased. In one of the two patients who continued to have seizures, IEA significantly increased. During therapy, the background activity presented significant increase of slow activity in approximately half the patients. This increase was more evident in those patients showing active epileptic foci before treatment, rather than in those with rare or no spikes. The changes in IEA seem to be related to the occurrence of seizures rather than to a direct action of CBZ on spikes.

Adolescent↗

PubMed1992

Effect of carbamazepine treatment on EEG changes induced by different cortical activation patterns in newly referred epileptic patients.

Sixteen epileptic patients suffering from focal epilepsy who underwent antiepileptic drug treatment with carbamazepine (CBZ) for the first time were studied. The EEG was recorded at rest with eyes closed, during blocking reaction (BR), fixation (FIX) and mental arithmetic tasks. The computerized EEG study, performed before and after CBZ therapy, utilized spectral analysis. Data underwent statistical evaluation through Anova and correlation analysis. The parameters evaluated were the mean frequency and the mean absolute and relative power. The results have shown that after CBZ treatment there is a decrease in the alpha reactivity during BR and FIX, while a significant increase in beta activity was observed during all tasks. The effect of CBZ therapy on EEG activity during cortical activation patterns are discussed.

Adult↗

PubMed1991

Comparison of neuropsychological, MRI and computerized EEG findings in a case of prosopoagnosia.

We present the case of a patient suffering from prosopoagnosia (PA). The MRI, performed at the onset of the disease, showed a lesion, strictly confined to the right temporo-occipital region; whereas the computerized EEG documented a functional impairment of the posterior regions of both hemispheres. A control performed two months later indicated a partial recovery of the neuropsychological deficit coupled with an improvement of EEG abnormalities, which was more prominent on the left side. The usefulness of functional studies in order better to comprehend the anatomical substrates of PA and their prognostic value are briefly discussed.

Adult↗