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Biomedical subjects

M G Marciani

Publications and source records attributed to M G Marciani.

At least 55 records · Page 3Linked to original sources
PubMed1995

Sodium valproate and mental processes in newly referred epileptic patients. A computerized EEG study.

Seventeen epileptic patients suffering from generalized idiopathic epilepsy who underwent antiepileptic treatment with sodium valproate (NaVPA) for the first time were studied. The EEG was recorded at rest with eyes closed (EC), during blocking reaction, fixation and mental arithmetic tasks. The computerized EEG study, performed before and after therapy, utilized spectral analysis; data underwent statistical evaluation including ANOVA and correlation analysis. Before NaVPA therapy, a significant decrease of beta 1 and beta 2 relative power, compared with control subjects, was observed in epileptic patients at rest with EC, whereas fast activity increased during mental tasks. After treatment, no significant variations in fast activity were observed during tasks, with a pattern similar to that observed in the control population. Therefore, considering the effect of NaVPA primarily on fast activity, which reflects rather well preserved mental functioning processes, it is possible to hypothesize that the drug interferes positively with mental activities.

Adolescent↗
PubMed1994

Lack of potentiation of anticonvulsant effect by fluoxetine in drug-resistant epilepsy.

To test the hypothesis that fluoxetine may be a useful adjunct to antiepileptic therapy, we treated with fluoxetine (20-40 mg/day) nine patients suffering from medically intractable epilepsy with daily seizures. Five patients remained unchanged and four worsened. Worsening was more evident at 40 mg/day. One patient improved when receiving the lower dose (20 mg/day) and worsened with the higher dose (40 mg/day). These data suggest: (1) that fluoxetine is not effective as add-on antiepileptic treatment; (2) that caution should be exerted when using fluoxetine as an antidepressive treatment in epileptic patients.

Adolescent↗
PubMed1994

Quantitative EEG evaluation in normal elderly subjects during mental processes: age-related changes.

Computerized EEG study was performed on 39 healthy elderly subjects (50-90 years), divided into two cohorts of increasing age (old, older) and on a group of 21 young controls. The EEG was recorded at rest, with eyes closed (EC) and during blocking reaction (BR), fixation (FIX) and mental arithmetic (MA) tasks. At rest with EC, the only significant variation was an increase of beta 1 relative power in old subjects which was positively correlated with age. During the performance of the mental tasks, in the elderly population when compared to young controls, the slow activity decreased slightly or was not significantly modified, while the alpha reactivity progressively decreased, showing a negative correlation with age in the older group. Beta 2 increased significantly in elderly subjects during BR and FIX but such change was less consistent with increasing age. Data show that at rest, the EEG in the elderly population differs only from that of young controls by showing a more pronounced fast activity, while only during mental processes is it possible to evidence changes that can be utilized as physiological "markers" of normal aging.

Adult↗
PubMed1993

Spastic paraplegia, epilepsy, and mental retardation in several members of a family: a novel genetic disorder.

We report on a family in which an association between spastic paraplegia and epilepsy has been observed. This disorder is an autosomal dominant trait with incomplete penetrance and variable expressivity. The onset was limited to the first four decades of life; the symptoms were typically those of progressive weakness and spasticity of lower limbs. Epilepsy was present in members of three of the four generations on whom we have information. The concomitance of spastic paraplegia and epilepsy in several members of the same family is unlikely to be fortuitous and probably represents the pleiotropic effect of a single mutant gene.

Adolescent↗
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

An electrophysiological study of D2 dopaminergic actions in normal human retina: a tool in Parkinson's disease.

A peculiar deficit of electrophysiological retinal responses to pattern reversal grating stimuli has been reported in Parkinson's disease (PD) patients. A similar abnormality has been reproduced by means of non-selective dopaminergic antagonists in normal humans. Aim of this study was to verify, by means of a selective D2 antagonist (sulpiride) administered to normal subjects, whether a D2 blockade affects the visual electrophysiological performances with the same trend as observed in PD patients. Patterns electroretinogram (PERG) responses to 1 cycle per degree (c/d) of spatial frequency at 1 (transient) and 7.5 (steady state) Hz of temporal modulation of a square-wave grating pattern reversal have been recorded in 19 healthy volunteers before and after the administration of 100 mg i.m. of sulpiride. The data are consistent for the following conclusion: a selective D2 antagonist reduces steady state and delays transient retinal responses as expected for a PD mimicking agent.

Adult↗
PubMed1992

EEG changes induced by carbamazepine therapy at rest and during mental processes.

The effects of carbamazepine (CBZ) on EEG background activity have been studied, at rest and during mental processes, in 18 epileptic patients suffering from focal epilepsy and starting antiepileptic treatment for the first time. The EEGs were recorded before and after CBZ therapy, at rest with eyes closed (EC), during blocking reaction (BR), fixation (FIX) and mental arithmetic (MA) tasks, and then evaluated by spectral analysis. All data underwent statistical evaluation utilizing the ANOVA and correlation coefficient. The following parameters were evaluated: mean absolute and relative power and mean frequency. The results have shown that CBZ induced a significant increase of slow activity at rest with EC, which was represented by delta potentials, and was correlated with CBZ plasma levels. In evaluating the different cortical activation patterns, a decrease of the alpha reactivity was noted during BR and FIX, while a significant increase of beta activity was observed during the performance of all tasks. The relationship between the increased beta power, possibly reflecting an increase of cognitive activity for processing information, and the lack of a significant decrease of alpha activity are discussed.

Adolescent↗
PubMed1992

Lateralization of the epileptogenic focus by computerized EEG study and neuropsychological evaluation.

The localization of the epileptogenic focus relies on different factors. In patients with partial seizures, asymmetries in EEG background activity were measured by a statistical evaluation of spectral data. Neurophysiological results were compared with neuropsychological findings and MRI. Fifteen of 22 patients showed asymmetries in EEG background activity. The most prominent abnormality was a statistically significant increase of slow activity observed in 59% of cases. Delta asymmetry coincided with the site of lesions, evidenced by MRI, in 83% of patients; with the site of decreased beta activity in 60% and with the maximum level of spiking activity in 58% of cases. Neuropsychological tests showed a lateralization of the hemispheric function which coincided with delta asymmetry in 33% of patients. These results suggest that the EEG background activity, when compared with other parameters, may represent a useful method in lateralizing the epileptogenic focus.

Adolescent↗
PubMed1991

Epileptic activity following cerebral ischemia in Mongolian gerbils is depressed by CPP, a competitive antagonist of the N-methyl-D-aspartate receptor.

A 10-min bilateral carotid occlusion (BCO) in Mongolian gerbils induces transient generalized epileptic discharges in the hippocampal and cortical regions, which are followed by long lasting interictal spiking activity. An initial peak of this activity occurs within 18-36 h after BCO, then it decreases slowly and completely disappears by the 6th-7th day. On the 7th day, morphological evidence shows a selective loss of CA1 hippocampal neurons. 4-(3-Phosphonopropyl)-2-piperazine-carboxylic acid (CPP), a competitive antagonist of the N-methyl-D-aspartate (NMDA) receptor was administered (7 or 15 mg/kg i.p.) immediately after clamping, and again every 12 h for 3 consecutive days. It induced a dose-related depression of epileptic activity, while, on the other hand, at both dosages, it always prevented the loss of CA1 neurons. The results are discussed in view of the different mechanisms mediating cell damage and epileptic activity.

Animals↗
PubMed1991

Non-Hodgkin lymphomas of the central nervous system.

Non-Hodgkin lymphomas (NHL) of the Central Nervous System (CNS) are rare but they nonetheless constitute a clinical, biological and therapeutic problem of great interest. Primary lymphomas of the CNS account for 2% of all malignant lymphomas and for 0.3-1.5% of all intracranial tumors. Surgery and radiotherapy afford only poor control of the disease. The most satisfactory results have been achieved with combination therapy, surgery + radiotherapy + chemotherapy, but the optimal combination has still to be devised. Secondary neuromeningeal involvement affects a fair number of patients with systemic NHL. The symptoms are broadly the same as in CNS NHL and the treatment as problematic. There have recently been suggestions that the onset of CNS NHL may be exacerbated by immunodeficiency states such as occur in patients who have undergone organ transplantation, in autoimmune disease and, still more recently, in the acquired immunodeficiency syndrome (AIDS). The frequency of these tumors is anyway on the increase and a better insight into the disease in essential.

Acquired Immunodeficiency Syndrome↗
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↗
PubMed1990

Dopaminergic pharmacological manipulations in normal humans confirm the specificity of the visual (PERG-VEP) and cognitive (P300) electrophysiological alterations in Parkinson's disease.

Retinal and occipital visual evoked potentials and event-related potentials (P300) have been recorded in normal human subjects before and after the administration of the dopaminergic receptor antagonist, haloperidol, and/or the dopaminergic precursor L-DOPA. The data show that either retinal or occipital visual potentials and P300 are delayed by haloperidol. These findings are consistent with the hypothesis that haloperidol in healthy subjects mimicks the electrophysiological abnormalities observed in Parkinson's disease. On the other hand, L-DOPA does not generally modify these latencies in normals, while it is known to decrease the same parameters in parkinsonian patients. This is in accord with the involvement of a specific mechanism in the recovery observed in parkinsonian patients after L-DOPA therapy. Our data confirm that the alterations of visual and cognitive potentials observed in Parkinson's disease are closely related to the impairment of dopaminergic transmission.

Acoustic Stimulation↗
PubMed1990

Intracerebral metastasis in Ewing's sarcoma.

The evidence of CNS involvement in Ewing's sarcoma is uncommon and very often due to a direct extension of the tumor to extradural space and meninges. We report a case of a 14-year old girl with a primary ischio-pubic localization of Ewing's sarcoma. Body CT scan showed a bone lesion involving the left fronto-temporal region of the skull without affecting the brain. After chemotherapy radiological findings showed complete recovery. Ten months after treatment, the patient had neurological symptoms. Cerebral CT scan evidenced a large tumor mass localized in the right temporal lobe. Following radiotherapy the tumor mass was no longer visible. This case shows that late intraparenchymal CNS metastasis occurs independently from the previous skull lesion. Therefore these data, even through based on a single observation, lead to believe that in some cases prophylactic chemotherapy and radiotherapy of CNS may not be necessary.

Adolescent↗
PubMed1987

Non-invasive evaluation of input-output characteristics of sensorimotor cerebral areas in healthy humans.

The topography of scalp SEPs to mixed and sensory median nerve (MN) and to musculocutaneous nerve stimulation was examined in 20 healthy subjects through multichannel (12-36) recording in a 50 msec post-stimulus epoch. MN-SEPs in both frontal leads were characterized by an N18, P20, N24, P28 complex showing maximal amplitude at contralateral parasagittal sites. This was sometimes partly obscured by a wide wave N30 having a fixed latency, but a steep amplitude gradient moving toward the scalp vertex. A P40 component followed, having longer peak latencies, moving the recording sites from contralateral medial parietal toward the vertex and frontal ipsilateral positions. MN-SEPs in contralateral parietal leads contained a widespread N20 with a maximum source posterior to the Cz-ear line. The following P25 enveloped two subcomponents - early and late P25 - having different distributions. The late P25 showed a maximum - coincident with that of wave N20 - which was localized more posteriorly than that of the early P25. An inconstant wave N33 with progressively longer peak latencies from sagittal toward lateral positions was then recorded. MN-SEPs in contralateral central positions showed a well-localized P22 wave in which both the parietal early P25 and the frontal P20 were vanishing. Common or separate generators for frontal, central and parietal SEPs were discriminated by evaluating the influence of stimulus rate and intensity, as well as of general anesthesia and transient CBF deficits, investigated in 7 patients undergoing carotid endarterectomy. Unifocal anodal threshold shocks were separately delivered to each of the scalp electrodes and motor action potentials were recorded from the target muscle in order to delineate the scalp representation of the motor strip for the upper limb and, consequently, to monitor, through SEP tracings, the short-latency sensory input to the motor cortex for hand and shoulder muscles. This was characterized by a boundary zone separating the parietal N20-early P25 complex, from the fronto-central N18-P22 one. This zone had an oblique direction strongly resembling that of the central sulcus.

Adult↗
PubMed1987

Monitoring of subcortical and cortical somatosensory evoked potentials during carotid endarterectomy: comparison with stump pressure levels.

Monitoring of multichannel somatosensory evoked potentials (SEPs) has been performed in 40 cases of carotid endarterectomy (CEA). SEPs were obtained after median nerve stimulation at wrist, recording from 2nd cervical and from the scalp parietal (ipsi- and contralateral) and central (contralateral) positions. The reduction of CBF due to clamping of the carotid artery provoked SEP abnormalities in 10 of the 40 cases. None of the 30 patients with unmodified SEPs developed post-surgical neurological sequelae. SEP alterations were characterized exclusively by amplitude decrements and latency increases of the cortical components, the subcortical ones being unaffected. In 5 of these patients, SEPs returned to normal values before the end of the intervention and no neurological deficit was observed on awakening. In the remaining 5 cases SEPs retained their abnormalities and patients developed post-surgery neurological sequelae (4 immediately, 1 the day after). SEP alterations affected parietal and central components to a similar extent; however, in a few cases cerebral blood flow deficits provoked by carotid clamping modified differently the central P22 and the parietal N20-P25 waves. Comparisons with stump (back) pressure in the carotid artery revealed a higher sensitivity of the SEP technique in detecting vascularization problems due to carotid clamping. The time course of the appearance of SEP abnormalities seems to discriminate alterations secondary to collateral revascularization from those determined by embolization.

Adult↗
PubMed1986

On the spinal pathways mediating scalp-SEPs to upper and lower limb nerve stimulation: case report and discussion.

Scalp-SEPs to peroneal nerve stimulation were abnormal in a patient with an intradural meningeoma which was compressing the antero-lateral quadrant of the 1st and, partly, the 2nd cervical myelomers. In contrast, spine and scalp-SEPs were symmetrically normal during the sural, median and ulnar nerve stimulation of either side. On surgery, it was observed that the tumor had left the dorsal columns (DCs) almost unaffected. It is argued, in agreement with the bulk of experimental evidence, that in humans the scalp-SEPs to lower mixed nerve stimulation are also mediated, at the rostral cord level, by fast-propagating tracts ascending outside the DCs.

Adult↗