Biomedical subjects

F Maestú

Publications and source records attributed to F Maestú.

At least 37 records · Page 2Linked to original sources

PubMedDate not supplied

[A study of the motor and sensory cortex using functional magnetic resonance: tasks of active and passive movement].

INTRODUCTION AND OBJECTIVE: The objective of this study was to locate the rolandic area (pre- and post-central) by means of functional magnetic resonance imaging (FMRI) and define its correspondence on a Talairach map, whilst active and passive movements of the dominant hand were performed. MATERIAL AND METHODS: Ten healthy volunteers were found, 6 men and 4 women, of an average age of 26 years (range 22-33). Two appropriate tasks were designed: one involving active and one passive movement. The examination was carried out using a 1.5 Tesla (General Electric) MRI apparatus. An echo-sequence of planar echo-gradient (BOLD technique) was used, making sagittal and axial planes, parallel to the AC-PC line (anterior commissure-posterior commissure). Subsequently an anatomofunctional Talairach map was drawn for each subject, to include the information obtained on FMRI. RESULTS: In all subjects central activity was detected in the rolandic area during the tasks involving selected active and passive movements. Overlap was seen between the pre- and post-rolandic areas with both types of tasks. CONCLUSION: There is good correlation between the image obtained of motor-sensory activity in the rolandic zone and the Talairach anatomofunctional map.

Adult↗

PubMedDate not supplied

[Neuropsychology and cognitive deterioration in epilepsy].

OBJECTIVE: To carry out a critical evaluation of the international literature on the neuropsychology of epilepsy. The variables which lead to cognitive deterioration in epilepsy and the effect on cognition of different treatments available (pharmacological and surgical). DEVELOPMENT: We evaluate the influence of different neurological variables on the higher functions (aetiology, age of onset, type of crises, duration of illness, frequency and anti-epileptic drugs). We also describe the cognitive functions most affected in epilepsy (memory, attention, executive function, language). Studies of the surgery of epilepsy show that this may lead to both beneficial and undesirable effects on cognition. CONCLUSIONS: The variables which in general most affect higher functions are the duration of the illness and the frequency and types of crises. The commonest neuropsychological effects are those of memory deficit. These studies show that neuropsychological studies should be done from the time of onset of the disorder. Finally, from the surgical point of view, young patients with considerable crisis reduction or free of crises, with moderate preoperative deterioration of memory have the greatest possibility of post-operative improvement in cognition. Older persons with intact cognitive function and major surgical resection have more possibilities of post-surgical deterioration.

Anticonvulsants↗

PubMedDate not supplied

[Psychometric validation of the telephone memory test].

INTRODUCTION: Several pathologies (i.e. Alzheimer's disease) that courses with memory alterations, appears in a context of impaired cognitive status and mobility. In recent years, several investigations were carried out in order to design short batteries that detect those subjects under risk of dementia. Some of this batteries were also design to be administrated over the telephone, trying to overcome the accessibility limitations of this patients. METHODOLOGY: In this paper we present a battery (called Autotest de Memoria) essentially composed by episodic and semantic memory tests, administered both over the telephone and face to face. This battery was employed in the cognitive assessment of healthy controls and subjects diagnosed as probable Alzheimer's disease patients. RESULTS: Results show the capability of this battery in order to discriminate patients and healthy controls, a great sensibility and specificity, and a nearly absolute parallelism of telephone and face to face administrations. CONCLUSION: These data led us to claim the usefulness and practicality of our so called < >.

Aged↗

PubMedDate not supplied

[Applications of the magnetoencephalography in the study of schizophrenia].

In this paper we present a revision about magnetoencephalography (MEG) and schizophrenia. We focus on Auditive Magnetic Fields, principally in M100 and in his hemispheric asymmetries. Finally, it was discussed the advantages of the MEG in comparison with other techniques with low temporal (RMf, PET) or spatial (EEG) resolution.

Brain↗

PubMedDate not supplied

[Evaluation of epilepsy surgery].

INTRODUCTION: Neuropsychology is a discipline included in the neurosciences which, over the past twenty years, has shown its value in the assessment and rehabilitation of cognitive functions in different disorders. In particular, in epilepsy it has permitted the description of the different factors which affect cognitive deterioration; permitted the establishment of profiles of cognitive deterioration and also the evaluation of the adverse effects of some anti-epileptic drugs on cognition. DEVELOPMENT: In this paper we confirm the value of neuropsychology in an Epilepsy Unit and describe different procedures for evaluation, as well as the cognitive consequences of the surgery of epilepsy.

Anticonvulsants↗

PubMedDate not supplied

[Neuropsychic injury: neuropsychological evaluation].

Traditionally assessment of cognitive function has not been employed adequately in our medical community. In the last two decades the neuropsychological assessment has experimented an evolution in order to improvement in specificity and sensitivity. In this paper we present a compendium of neuropsychological test that could be evaluate cognitive function adequately.

Cognition Disorders↗

PubMedDate not supplied

[Neuropsychology of temporal partial epilepsy: a comparison of drug resistant and pharmacologically controlled patients].

INTRODUCTION: Various factors may contribute to cognitive deterioration in temporal lobe epilepsy, and there is controversy as to which has the greatest effect. PATIENTS AND METHODS: In this study, we establish a comparison between patients with temporal lobe epilepsy controlled by drugs and drug-resistant patients, with the object of discovering the effect of different factors in causing cognitive damage. RESULTS: The persons whose disorder was controlled by pharmacological means had better results in memory and intelligence tests than those with drug-resistance. The latter had alterations of declarative memory for verbal material (left) and for visio-spatial material (right) in delayed free recall tests. Also, the greater proportion of symptomatic epilepsies in the drug-resistant group affected their greater cognitive deterioration. CONCLUSIONS: Our results show that having long-standing epilepsy with great frequency of seizures and symptomatic epilepsy is correlated with cognitive alterations in memory function in temporal lobe epilepsy. Most deterioration is seen in patients with long-standing drug resistant symptomatic left mesial temporal epilepsy.

Adolescent↗

PubMedDate not supplied

[New advances in neuroimaging in the diagnosis of obsessive-compulsive disorder].

Brain-imaging research provides evidence to suggest that the underlying disfunction in Obsessive-Compulsive Disorder (OCD) is likely to be in the prefrontal cortex-basal ganglia thalamic circuit rather then in any one single brain region. Early computerized tomography and magnetic resonance imaging studies have shown morphological changes in the basal ganglia. Now more sophisticated techniques are enhancing the information available, specially with regard to the caudate nucleus. The serotonergic hypothesis remains a necessary but not sufficient explanation for the pathogenesis of OCD. Most evidence remains focussed on the basal ganglia and on a 5-HT/dopamine inter-relationship. Given the basal ganglia receive such rich innervation from both 5-Th and dopamine neurones, it has been postulated that OCD is subserved by a neuronal dysfunction in the basal ganglia and orbitofrontal cortex circuit. Combining behavioural challenge with brain imaging may be a better approach to capturing brain function while patients with OCD and control subjects are actually observed. Using this techniques has made it possible to identified changes in response to treatment, whether the treatment is pharmacological or behavioural. However, there are not data enough that allow us to understand the anatomical, physiological and chemical mechanisms implicated in OCD.

Basal Ganglia↗

PubMedDate not supplied

[Cerebral perfusion during word repetition in epileptic patients].

OBJECTIVE: To localize the cortical regions for language in patients who are to have brain surgery. PATIENTS AND METHODS: We made a SPECT (Single Photon Emission using Computerized Tomography) study of cerebral perfusion in 14 patients with drug-resistant temporal epilepsy who were candidates for brain surgery. The patients were selected consecutively from those attending for surgical assessment. We selected the patients in whom two 99mTc-HMPAO studies could be done in the same week: one without sensory stimulation and one whilst listening and repeating a series of ordinary words in fairly frequent use. The two studies were assessed qualitatively (on a 16 colour image scale, with a background subtraction of 20% and standardized to the point of maximum uptake). Changes were considered to be significant when a greater intensity of two colours was localized and semiquantitative (with regular areas of interest, of 4 x 4 pixels, placed on the region in which the qualitative change was observed and referenced to cerebellar activity). RESULTS: We found increased perfusion in the temporo-parietal regions in 11 of the 14 patients. In most (9/14 cases) this was bilateral and in two cases on the left only. We observed a certain predominant pattern: a bilateral increase in temporal perfusion, involving the more anterior regions of the left hemisphere and also the middle and posterior regions of the right hemisphere. The maximum percentage increase in perfusion on semiquantitative assessment was 12%. CONCLUSION: Although the changes seen may correspond to activation in the cortical regions related to different cerebral functions, we consider that with the SPECT technique one may detect changes in perfusion of the regions of the brain which are involved in language processing.

Adolescent↗

PubMedDate not supplied

[Atrophy of the amygdala complex and neuropsychiatric expression of Alzheimer s disease].

INTRODUCTION: In Alzheimer s disease, together with cognitive changes (loss of memory, lack of orientation in time and space, difficulty in carrying things out, etc.) non cognitive disorders also occur, seriously disturbing the patient s behavioral and emotional balance. Depression, delirious ideas, hallucinations and behavior changes (habits regarding sex, feeding and movement) are amongst the commonest features of this disease from its earliest stages. Several studies have described how initially the histopathological changes selectively involve different structures of the medial temporal lobe ( entorinal cortex, hippocampal formation, amygdala) and gradually includes neocortical association areas. Thus, the amygdala complex, a structure related to processes of memory and emotional control, is severely affected in this disease from the initial stages. PATIENTS AND METHODS: Therefore, to find any possible relationship between involvement of the amygdala and the psychiatric expression of Alzheimer s type dementia, we did a radiological study, using magnetic resonance, together with a neuropsychological study of a group of 24 persons with Alzheimer s disease who had mild moderate deterioration. Analysis of the amygdala area and the scores on the subtest Alzheimer s Disease Assessment Scale Non cognitive (ADAS NC) were the variables chosen for measurement of the anatomical and psychiatric aspects of the subjects under investigation. RESULTS AND CONCLUSIONS: The results of our study show a close relation between involvement of the amygdala (atrophy) and the presence of neuropsychiatric changes in persons with Alzheimer s disease.

Aged↗

PubMedDate not supplied

[Magnetoencephalographic study in patients with cognitive impairment].

INTRODUCTION: In early stages, dementia is a neurodegenerative process with difficult diagnosis. Although well defined clinically, its neurophysiological, neuroradiological and metabolic diagnosis is still unsuccessful. PATIENTS AND METHOD: A MEG study using a 148 channel whole head magnetometer (Magnes 2500 WH) and evaluation by mini mental state examination (MMSE) was performed in 31 subjects. Statistical analyses was made to correlate number of dipoles of slow waves and neuropsychological variables. RESULTS: The 63.3% (21 patients) show slow waves dipoles in temporal lobes (52.3% were bitemporal). Right temporal lobe has 119.5 23.3 dipoles (averaged value), and left temporal lobe has 126.2 19.8 dipoles (averaged value). The 25% (8 patients) shown slow waves dipoles in parietals lobes, 5 of them biparietal. Correlation between MMSE averaged scores and temporal lobe dipoles was r= 0.84. CONCLUSION: MEG results show that slow waves dipoles number in temporal lobes is related with low scores in the mini mental state examination. MEG could be a usefully complementary method in evaluation and following of degree of cognitive impairment in these patients

Aged↗

PubMedDate not supplied

[Cognition and neural networks, a new perspective based on functional neuroimaging].

AIM: We went through a critical review of the current status of neuroimaging studies of cognition. Thus, we argue why the use of a neuronal network perspective could led us to a better understanding of cognition than a localizationism perspective. METHOD: The question about how cognitive functions are organized in the brain, comes from the very early lesions studies. Electrocortical stimulation and the intracorotid amytal procedure collaborate together with lesions studies to increase the knowledge about the organization of cognitive functions in the brain. Functional neuroimaging could help to this issue answering the following questions: where, when and how the activity is produced in the brain. Many of the functional neuroimaging studies have addressed the question of where the activity is located, but very few has been concentrated into describe the spatio temporal profiles of brain activity, and then how the neural networks which support cognition are organized. Taking into account just one of this perspectives (where or when) we could achieve a reductionism view of the problem. CONCLUSIONS: Executive function, memory or language are more distributed than located in just one area, even the different subprocesses that are included in each of this functions are supported by a network rather than a particular area. We analyze the current available functional neuroimaging techniques under this view and its possibilities to describe the neural networks which support cognition.

Brain↗

PubMedDate not supplied

[Functional neuroimaging applied to the study of neuropsychological rehabilitation].

OBJECTIVE: We review the main aspects of functional recovery after brain injury as well as neuroimaging characteristics that make it relevant and useful to assess these changes. We also review some issues regarding recovery of motor and sensory functions, language and visuo spatial processes, and we discuss the methods used in this field, the difficulties found, and future implications. DEVELOPMENT: One of the main aspects in the study of the brain is the capacity to reorganize different functions in order to compensate for the deficits after a lesion in the central nervous system. The study of these adaptive processes is important in a clinical field as well as for basic research, as it is a clear example of brain plasticity. All the findings show how the study of the plastic phenomena or functional reorganization will allow us to better know how the brain works after a lesion. CONCLUSION: The use and combination of the new functional neuroimaging techniques gives the opportunity to register the reorganization of the brain with a high temporal and spatial resolution. It will give also an objective measure to assess the effectiveness of the rehabilitation programs. It will allow to identify different variables related to rehabilitation outcome and will guide effectively the selection of different rehabilitation approaches.

Brain Injuries↗

PubMedDate not supplied

[Magnetoencephalography in cognitive disorders involving frontal lobes].

INTRODUCTION AND DEVELOPMENT: Frontal lobe, more specifically prefrontal cortex, is one of the brain regions that undergoes more protracted ongoing development. The wider the developmental window of one brain structure, the more vulnerable the functions related to it. Hence, executive functions, which are mediated by prefrontal networks, seems to be specially vulnerable during childhood. Attention-deficit/hyperactivity disorder (ADHD) is one of the most prevalent neurodevelopmental disorders. Functional neuroimaging techniques have shown a dysfunction in a fronto-striatal network in this disorder, that is likely subserving deficits in executive processes, such as in response inhibition. DISCUSSION: This review focuses on contributions of neuroimaging techniques, with high spatial (SPECT, PET and fMRI), temporal (ERP) and spatio-temporal (MEG) resolution, to the neurofunctionality of ADHD.

Attention Deficit Disorder with Hyperactivity↗

PubMedDate not supplied

[Emergence and brain development of executive functions].

Development of executive functions (EF) during childhood and adolescence is closely related to frontal lobe maturation and its connections with other cortical and subcortical structures. The main maturative processes are myelination and synaptic pruning, both of which work on the brain following a hierarchical model. Different studies agree with the fact that EF emerge at the age of 6 years. However, these studies have used complex neuropsychological tests, which require appropriate functioning of several cognitive functions. This is why differential development of different EF components cannot be observed. To do so, other studies have designed simpler tasks, which only need active maintenance of information and inhibition, both basic functions for the appropriate execution of more complex EF tasks. When these simple tasks are used, an early appearance of EF can already be noticed at the age of 12 months, and there are important advances between the third and fifth year. Consequently, the idea of the frontal lobe being "functionally silent" until adolescence seems definitively discarded.

Brain↗

PubMedDate not supplied

[Pharmacoresistant temporal-lobe epilepsy. Exploration with foramen ovale electrodes and surgical outcomes].

AIM: To report our experience in the surgical treatment of temporal-lobe epilepsy. PATIENTS AND METHODS: An analysis was performed of the outcomes of 137 patients submitted to surgery between 1990 and 2001, with a follow-up of more than two years. A study was conducted of the percentages of successful detection by the different complementary tests--MRI, EEG, interictal SPECT, video-EEG with foramen ovale electrodes (FOE), neuropsychological study (NPS)--and the precision with which they reported the epileptogenic focus. RESULTS AND CONCLUSIONS: Successful surgical outcomes (Engel grades I-II): 73.4%. No surgical mortality occurred, although some mild, reversible morbidity was observed. Surgical outcomes were not affected by sex, age, age of onset and the length of time the patient had had the disease, or the frequency of the seizures. No association was found between seizures in the immediate post-operative period and a poorer long term control of the epilepsy. MR images were normal in 25% of patients; in these cases the surgical outcomes (Engel grades I-II at two years: 62%) were significantly poorer than in cases of tumours/cavernomas (86%); RMI studies of other types of lesions gave intermediate results (72%). With respect to the capacity of the different tests to lateralise/locate the epileptogenic focus, video-EEG-FOE proved to be the best, followed by MRI, SPECT, EEG and NPS.

Adolescent↗

PubMedDate not supplied

[Frontal seizures recorded by magnetoencephalography. Case report].

INTRODUCTION: This paper reports the usefulness of magnetoencephalography (MEG) in the anatomical localization of the onset and spread of seizures. CASE REPORT: In a 34-year-old male patient who suffered from drug-resistant complex partial seizures (sometimes generalized) with loss of awareness, magnetic resonance imaging revealed a probable left frontobasal cortical dysplasia. Ictal scalp electroencephalogram showed left frontotemporal theta waves. Electrocorticography (ECoG) registered interictal polyspike discharges and located the seizure onset in the lateral orbital side of the left frontal lobe. Three seizures were registered by MEG, clinically similar to the ones usually experienced by the patient. MEG ictal spike dipole location showed seizure onset coming from the left inferior frontal gyrus (as the ECoG), spreading on to other frontal areas, insula and temporal lobe, all in the left hemisphere. CONCLUSION: MEG may be considered as a useful diagnosis modality in the study of partial seizure physiopathology as well as in its presurgical evaluation.

Adult↗

PubMedDate not supplied

[Movement alterations following cerebrovascular damage in the intact hemisphere ipsilateral to the affected upper limb].

OBJECTIVE: We analyze the explanatory hypotheses proposed in most relevant studies on the different altered movements (AM) in the unaffected part of the body following a stroke. We report 25 cases of AM patients whose clinical signs do not correspond with the AM described in previous studies. A possible explanation could be established from a different neuroplastic hypothesis. DEVELOPMENT: To review the main hypotheses which try to explain the presence of AM in the part of the body ipsilesional to the injured hemisphere of the brain. To this end we overview some updated studies concerning the corticospinal tract function, and the neuroplastic capacity after a stroke. Simultaneously, we study 25 cases of patients with cerebrovascular disease and some clinical findings which present a different type of AM from those previously reported. CONCLUSIONS: Motor alterations described in most studies concerning stroke patients correspond well to a diminished selectivity of movements of the unaffected hand, to associated movements in both upper limbs or to mirror movements. Explanations of these hypothesis are: the effect of injured fibres of the uncrossed corticospinal tract and neuroplastic reorganization of the ipsilateral pathways. The existence of different AM is observed in some clinical cases which we found to be scarcely studied in published research. These movements appear in the non-affected part of the body throughout cerebrovascular disease evolution, and which could be caused by maintained hypersolicitation of the unaffected part of the body and the neuroplastic process following a stroke. Further functional neuroimaging investigations are needed to confirm this clinical hypothesis.

Cerebrovascular Disorders↗