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M A Pozo

Publications and source records attributed to M A Pozo.

23 records · Page 2Linked to original sources
PubMedDate not supplied

[The P300 component of evoked potentials in the evaluation of schizophrenia: new evidence and future visions].

OBJECTIVE: To analyze the character as pathophysiological marker of the P300 component in the evaluation of schizophrenic illness. We therefore review clinical and neuropsychological evidence of studies in which this was used as a tool for evaluation to reach a diagnosis. DEVELOPMENT: The P300 component is useful for studying not only cognitive processes but also the physiopathology of complex disorders such as schizophrenia. This component reflects the state of functions of attention control and memory, both necessary for final evaluation of a stimulus. These cognitive functions become altered in schizophrenic illness, as is shown by abnormality in the generation of the P300 component. We review the most relevant results, which permit characterization of the many features of schizophrenia from genetic, symptom, morphology and neuropsychological studies in which the P300 component is particularly relevant. Similarly, we analyze current controversies due to the great heterogeneity of methodology and the nature of the illness itself. CONCLUSIONS: Current understanding allows us to establish that the P300 is a biological marker of relevant aspects of schizophrenia such as the genetic risk of suffering a psychotic episode, determine the type and gravity of the symptoms of the disease, as well as the degree of structural deterioration of the patient. The P300 component is sensitive to the effect of different neuroleptic drugs, on both the symptoms and neuropsychological functions of the patient. These findings let us suggest the P300 component as a valid marker for the evaluation of schizophrenia and the neuropsychological processes.

Adult↗
PubMedDate not supplied

[Localization of the epileptogenic zone by analysis of electroencephalographic dipole].

INTRODUCTION: In partial epilepsy with seizures which are resistant to drug treatment, better results may be obtained with surgery. This follows thorough assessment to identify the area of the brain responsible for the origin of the seizures, or the epileptogenic zone (EZ), and show that surgical operation will not cause neurological or cognitive damage which might handicap the patient. OBJECTIVE: This study analyses the value in diagnosis of electroencephalographic dipoles in delimitation of the EZ in patients with refractory partial epilepsy who are candidates for surgical treatment. PATIENTS AND METHODS: In 43 patients we made EEG recordings whilst at rest with their eyes shut during 15 minutes. The signal was analysed by digital EEG apparatus and a map drawn of cerebral electrical activity based on the maximum average amplitude of the epileptic spikes. The electric dipole equivalent to epileptiform activity between seizures was obtained using the programme for analysis of electroencephalographic sources BESA. The localization of the EZ by means of the dipole was compared with the results of EEG, MR, SPECT and seizure video-EEG using intracranial electrodes. RESULTS: The results of this study show that the dipole model used is highly sensitive for localization of EZ, and in cases in which the dipole and MR coincided, its sensitivity is similar to that of video-EEG during seizures. CONCLUSIONS: The model of dipole used in this study is of great help when indicating surgery for patients with drug-resistant epilepsy.

Anticonvulsants↗
PubMedDate not supplied

[In vivo and in vitro neurophysiological features of epilepsy].

INTRODUCTION: Some electrophysiological aspects of the interictal activity in temporal lobe epilepsy (TLE) are under debate. However, surgery is often guided by both, pre and intra operative recordings of interictal activity. Some of these studies include intraoperative electrocorticography (ECoG) that guide tailored resection. OBJECTIVE: To analyze several aspects of interictal activity recorded by ECoG and to explore its electrophysiological basis in vitro. PATIENTS AND METHODS: ECoGs from thirteen patients suffering drug resistant TLE were analyzed. Both linear and non linear methods were introduced to explore the ECoG signals. In two cases, neocortical tissue was also electrophysiologically studied in vitro. RESULTS: Interictal ECoG activity showed a mesial origin, a cortical origin or a mixed mesial/temporal origin. Both in cortical and mesial/cortical origin, cortical interictal ECoG signals are characterized by spatiotemporal clusters of activity. In vitro study of cortical tissue from these clusters showed alterations in the synaptic control of excitability. CONCLUSION: Our results suggest an electrophysiological basis of interictal activity. Combination of linear and non linear methods is a very useful tool to explore on line the interictal ECoG activity during surgery.

6-Cyano-7-nitroquinoxaline-2,3-dione↗