Biomedical subjects

A Fernández-Lucas

Publications and source records attributed to A Fernández-Lucas.

11 recordsLinked to original sources

PubMed2006

[A comparative study of pragmatic language disorders and autism spectrum disorders using magnetoencephalography].

INTRODUCTION: Pragmatics refers to the social use of language; its precursors are already present during the process of maturing, during the preverbal stage, and become manifest when the child starts to point and to share his or her attention with another person. In cases of specific language impairment (SLI) and autism spectrum disorders (ASD) it can be altered to varying degrees. PATIENTS AND METHODS: Due to the difficulties involved in diagnosis from a clinical point of view, we carried out a study by means of magnetoencephalography (MEG) on a series of 11 patients who had SLI and another series of 9 patients with ASD, in order to determine whether MEG is capable of distinguishing these diagnoses. RESULTS: Patients with SLI displayed pathological activity in the frontal and middle temporal regions of both hemispheres. Patients with ASD showed pathological activity in the perisylvian area. Expressive-receptive SLI with pragmatic language disorder showed pathological activity that was similar to that seen in autism. CONCLUSION: MEG can be used to distinguish between SLI and ASD by studying the epileptiform activity that occurs in pervasive developmental disorders. MEG helps us to understand the continuum that exists between SLI or expressive-receptive SLI and autism.

Autistic Disorder↗

PubMed2003

[Neuromagnetic correlates of dyslexia].

Dyslexia was first described over a century ago and since then many theories have been put forward to explain it, but we still do not have one single unified theory that explains the problem. Furthermore, over the years a great deal of research work has also been carried out that relates dyslexia with disorders in different brain structures, and yet we still do not have a clear idea of exactly which neurophysiological mechanisms are involved. It has been claimed, however, that the disorder may be caused by specific deficits in the left frontotemporal region or atypical asymmetries in the left perisylvian regions. Lastly, neuroimaging techniques, such as functional magnetic resonance or mapping of the electrical activity in the brain, have helped to further studies into dyslexia over the last decade. Recently, the introduction of magnetoencephalography in the study of the brain has opened up a whole new range of possibilities that will allow most of the controversial points raised by research into dyslexia using neuroimaging techniques to be resolved empirically.

Child↗

PubMed2003

[The neuromagnetic correlates of language].

Studies of language using different functional neuroimaging techniques have shown the cortical structures to be involved in the functions of language, both in control subjects and in patients with different neurological pathologies who are to undergo brain surgery. Magnetoencephalography (MEG) is a totally non-invasive technique that measures the magnetic fields generated by the flow of intracellular current produced in the dendrites of the pyramidal neurones. MEG also offers the possibility of lateralizing language, so enabling us to know which areas of language lie within the dominant hemisphere and to establish the temporal patterns that reveal the organisation, either in sequence or in parallel, of the different areas that are activated. This will provide us with a deeper understanding of the physiological foundations upholding both language and other cognitive processes.

Adult↗

PubMed2003

[Clinical features of epilepsy in autism spectrum disorders].

Autism is a rare disease, but is currently in vogue. An incidence of 1/1,000 has been estimated for early childhood autism, but in autism spectrum the incidence can reach 30/1,000. The clinical characteristics of autism are cognitive language disorders, lack of social interaction, obsessive behaviours with stereotypic movements and epilepsy. For some authors it is an associated symptom while for others it is a cardinal symptom of the disease. Epilepsy in autism, as an association, was reported as early as 1944 by Leo Kanner, in describing his initial work involving 11 cases and how one of them suffered from epilepsy. In 1960, the prevalence of epilepsy among autistic patients was evaluated and found to be much higher than in the normal population. The figures differ from author to author, but really they depend on age: the higher the age, the greater the prevalence of epilepsy. It was in fact this detail that drew our attention to this issue, and triggered the first questions in our research into autism and epilepsy. The series vary from 4 to 86%, depending on the methodology used to confirm the epilepsy. In our casuistics, between the ages of 1 and 18 years, 20% of these children with autism spectrum disorders suffer some kind of epileptic seizures, and 80% suffer what other researchers call subclinical seizures . In this paper, the symptomatology of the most important subclinical seizures that have been observed in these children is presented; the diseases associated with autism are commented on; the concept of primary and secondary autism is discussed; we explain why seizures occur in autism and their consequences as a neurodevelopmental disorder, and we put forward an interesting hypothesis within our general theory of autism. We also comment on the importance that the use of functional magnetic images in the study of autism has in our research.

Adolescent↗

PubMed2003

[Savant or idiot savant syndrome].

Savant syndrome is currently still very mysterious, yet, thanks to the progress made in neuroimaging studies and especially MSI (Magnetic Source Imaging) techniques, a little more is now known about it. The theory, formulated many years ago, about damage to the left hemisphere of the brain has been supported by functional neuroimaging. Its relation to developmental disorders or to autism spectrum disorders is far more justified today and can be explained on the basis of its neuropathology. We present a study based on a review of the scientific literature concerning the syndrome, from the first time it was described back in 1789 by Benjamin Rush up to the present day. We comment on its epidemiology and positive clinical manifestations, involving brilliant artistic talent and dazzling memory, but also the negative aspects suffered by these autistic patients. The most important theories are discussed together with the clinical coincidence with frontotemporal dementia and the responsibility of the right hemisphere when there are alterations in the contralateral hemisphere. The latest contributions made by Positron Emission Tomography and magnetoencephalography will be discussed and a mini-video of a personal case will be projected.

Art↗

PubMedDate not supplied

[Electromyographic response associated with capsular stroke].

INTRODUCTION: Lesions of the pyramidal system are characterized by their effects on qualitative aspects of movement. One of the features of pyramidal defects is the presence of associated movements or synkinesis. CLINICAL CASE: We present a case with residual associated electromyographic (EMG) response in a patient who had had a capsular stroke 11 months previously. The patient presented with acute onset of a syndrome of purely motor right hemiparesis (PMH) which improved satisfactorily with complete functional recovery three months later. Eleven months after the acute episode, there was good functional recovery and neurophysiological examination showed the presence of EMG responses associated with the unaffected limb (left hand) when voluntary movements were made with the right hand. CONCLUSION: The appearance of qualitative alterations of movement associated with pyramidal syndromes and particularly the presence of associated EMG responses in the case of capsular infarct described, may reflect the different processes of reinnervation and functional reorganization which occur following the lesion and which are involved in recovery of motor function.

Acute Disease↗

PubMedDate not supplied

[Rolandic discharges in childhood epilepsy: magnetoencephalographic diagnosis].

INTRODUCTION: Whole head magnetoencephalography (MEG) systems facilitate simultaneous recording from the entire brain surface and deep structures. Thus MEG may be accepted as a clinically feasible method for the evaluation of epileptic patients not diagnosed with EEG. CLINICAL CASE: A 11 year old female, with tonic generalized seizures since birth. At the present time, seizures consist of initial focal signs followed by fear sensation and both eyes and cephalic deviation to the right, tonic extension of the superior limbs and prolonged apnea. Complementary examinations (EEG, Holter EEG, Video EEG, CT, MRI, SPECT) were normal. MEG study was conclusive, diagnosing sharp waves in the internal face of the left precentral circunvolution. CONCLUSIONS: MEG study s utility in seizures focus localization and pseudo seizures differential diagnosis has been demonstrated.

Anti-Anxiety Agents↗

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

[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

[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↗