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S Arroyo

Publications and source records attributed to S Arroyo.

At least 55 records · Page 3Linked to original sources
PubMed1993

Functional significance of the mu rhythm of human cortex: an electrophysiologic study with subdural electrodes.

The existence of the mu rhythm and its general anatomical and physiological relationships are well known. There are few data, however, regarding the details of its anatomical and physiological specificity. We implanted fronto-temporal subdural electrode grids in 9 patients with intractable epilepsy to facilitate their surgical management. A 7-11 Hz cortical mu rhythm was observed in 5-16 electrodes located over the sensorimotor cortex as mapped by electrical stimulation. The mu rhythm was blocked by contralateral face and arm movements, passive movements of contralateral arm, and by ipsilateral arm movements. There was correspondence between the body area movement of which blocked the mu at a given site and the body region that was affected by stimulation at the same site. Power spectral analysis showed an overall decrease in power in all frequency bands. This was less prominent in the 14-100 Hz band resulting in a relative increase in high frequency power in association with movement. We conclude that both the presence and blocking of mu rhythm are specific to the somatic representation of the cortex from which it is recorded. Its functional significance may be similar to other sensory rhythms like the occipital alpha rhythm.

Adolescent↗
PubMed1993

Mirth, laughter and gelastic seizures.

Little is known about what pathways subserve mirth and its expression laughter. We present three patients with gelastic seizures and laughter elicited by electrical stimulation of the cortex who provide some insight into the mechanisms of laughter and its emotional concomitants. The first patient had seizures manifested by laughter without a subjective feeling of mirth. Magnetic resonance imaging showed a cavernous haemangioma in the left superior mesial frontal region. Ictal subdural electrode recording showed the seizure onset to be in the left anterior cingulate gyrus. Removal of the lesion and of the seizure focus rendered the patient virtually seizure free over 16 months of follow-up. The other two patients had complex partial seizures of temporal lobe origin. Electrical stimulation of the fusiform gyrus and parahippocampal gyrus produced bursts of laughter accompanied by a feeling of mirth. These cases reveal a high likelihood of cingulate and basal temporal cortex contribution to laughter and mirth in humans, and suggest the possibility that the anterior cingulate region is involved in the motor act of laughter, while the basal temporal cortex is involved in processing of laughter's emotional content in man.

Adult↗
PubMed1992

Anterior "cheek" electrodes are comparable to sphenoidal electrodes for the identification of ictal activity.

Sphenoidal electrodes are used to localize epileptiform activity originating in the temporal lobe during complex partial seizures. Sphenoidal electrodes, however, are semi-invasive and uncomfortable to the patient. We compared skin electrodes placed on the cheek ("cheek electrodes") with sphenoidal electrodes for the detection of the side and site of complex partial seizure onset. In a masked, randomized comparison of single ictal recordings in 22 patients, there were no significant differences between sphenoidal and cheek electrode montages in detecting the side or site of ictal onset (P < 0.01). Signal/noise ratios for interictal spikes were a mean 16.5% greater at sphenoidal sites compared to cheek sites (paired t test, t = 2.4, P < 0.05). This difference, however, did not influence the detection of rhythmical ictal activity in cheek and sphenoidal montages in our study, nor the assignment of side, site or time of seizure onset by unbiased readers. Recordings from cheek electrodes are comparable to those from sphenoidal electrodes and are useful for localizing ictal activity.

Cheek↗
PubMed1992

High-frequency EEG activity at the start of seizures.

Frequencies above 35-40 Hz are poorly visualized on conventional EEG scalp recordings. We investigated frequency components up to 150 Hz in digitally recorded EEGs of seizures in five patients with implanted subdural grids, as part of their evaluation for epilepsy surgery. Amplifier bandpass was set from 0.1 to 300 Hz, and EEG was digitized at 2,000 samples per second. Seizures with electrodecremental patterns at the start showed a significant increase in spectral power above 35 Hz, with a twofold increase in the 40-50-Hz range, and up to a fivefold increase in the 80-120-Hz portion of the spectrum. Activity above 40 Hz could represent summed action potentials, harmonics of synaptic potentials or transient sharp components of synaptic potentials. High-frequency increases were largely localized to the region of the seizure focus. Grid sites remote from the focus did not show significant energy in the EEG band above 40 Hz at baseline, nor at time of seizure onset. Our findings suggest that high-frequency recordings may be of use in localizing seizure foci.

Adolescent↗
PubMed1992

Simple partial seizures: clinicofunctional correlation--a case report.

A 12-year-old girl developed simple partial motor and sensory seizures due to a right perirolandic astrocytoma. Subdural EEG recording and functional stimulation disclosed close correlation between EEG-clinical manifestations of focal seizures and functional responses to cortical stimulation. This case supports the idea that responses in the perirolandic area to endogenous epileptogenic activity and to cortical stimulation reflect common underlying physiologic mechanisms.

Brain↗
PubMed1990

[Complicated migraine: a study of 7 cases].

The association between migraine and stroke is well known. It is assumed that 15% of strokes in patients below 45 years are due to migraine. To evaluate the features of this association, we have reviewed seven cases of patients with migraine and established neurological deficits. All patients fulfilled the following criteria: 1) past history of migraine, defined on the basis of the classification by the International Committee for the Classification of Headache; 2) temporal association between a migraine episode, similar to previous ones, and the ischemic episode, and 3) absence of other concomitant diseases that might result in stroke. We evaluated the age at the onset of migraine, its type, familial history of migraine (particularly of migrainous accompaniments), vascular risk factors, mode of onset, and type and duration of neurological deficit. In all cases, cranial CT, EEG, echocardiogram, serologic tests for syphilis, autoantibody investigation, routine laboratory tests and nuclear magnetic resonance (in four patients). In five cases cerebral arteriography was carried out, and arterial occlusion was demonstrated in one. We conclude that, in spite of its low frequency, migraine may result in cerebral ischemic episodes, although the relevant pathogenetic mechanisms are not yet well understood.

Adolescent↗
PubMedDate not supplied

Clinical and electroencephalographic evidence for sites of origin of seizures with diffuse electrodecremental pattern.

A diffuse electrodecremental ictal pattern (DEP) has been associated with tonic seizures and, less often, with other forms of epilepsy and has been considered to reflect a generalized seizure disorder of diffuse cortical or subcortical (brainstem) origin. In some seizures associated with DEP, however, focal ictal manifestations have been observed. We reviewed the records of all patients admitted to our seizure monitoring unit for 3 years and detected 39 patients with seizures associated with DEP. In 23 of 39 patients, clinical ictal behaviors resembled seizures of unilateral supero/mesiofrontal lobe origin and interictal EEG showed a prominent unilateral frontal component. Nine of 39 had complex absences (CA)/complex partial seizures (CPS); 4 of them were of unilateral frontal lobe origin. Seven of 39 patients had tonic or atonic seizures. Seven patients were studied further with subdural electrodes. Ictal onsets showed a high-frequency frontal lobe discharge. We conclude that in a subgroup of patients a generalized electrodecremental pattern on scalp EEG results from a regional cortical high-frequency ictal discharge originating in a single frontal lobe.

Adult↗
PubMedDate not supplied

[The treatment of epilepsy in medical conditions, geriatric and pregnant patients].

INTRODUCTION: Treatment with antiepileptic drugs in patients with medical conditions, old age or pregnancy is associated with concomitant pathology and the specific physiopathological changes of age or pregnancy. DEVELOPMENT: The difficulties of treatment in special conditions are related to changes in the pharmacokinetics of antiepileptic drugs, interaction with other medication and with concomitant treatment with drugs which may potentially cause convulsions. Also, the occurrence of a particular disorder or of pregnancy may lead to changes in the frequency of crises. Besides this, the side-effects of antiepileptic drugs may be more marked or more frequent in patients with several other conditions or in the elderly. CONCLUSION: The treatment of epilepsy in patients with associated medical disorders, old age or pregnancy requires knowledge of the behaviour of antiepileptic drugs and the physiopathology of these conditions.

Adult↗
PubMedDate not supplied

[The treatment of epilepsy. A therapeutic guide of the Catalan Society of Neurology].

INTRODUCTION: There have been major advances in the treatment of epilepsy over the past ten years, leading to marked changes in the way this illness is treated. However, the introduction of new drugs and new non-drug treatments have led to uncertainty in the medical profession with regard to their exact indications. For this reason, a group of neurologists of the Catalan Society of Neurology have drawn up guide-lines for the treatment of epilepsy. DEVELOPMENT: A panel of eight neurologists with a special interest in the diagnosis and treatment of epilepsy reviewed the literature to assess the data available regarding the treatment of epilepsy. A joint document was drawn up describing the basic rules for the use of antiepileptic drugs and the indications for other non-drug treatments. CONCLUSION: This document is an approved therapeutic guide to the treatment of epilepsy.

Dose-Response Relationship, Drug↗
PubMedDate not supplied

[Evaluation of drug-resistant epilepsy].

OBJECTIVE: Drug-resistant epilepsy makes up between 10 and 30% of all epilepsies, and is an important cause of morbidity and mortality. In this article we review the guidelines and techniques used when assessing a patient with drug-resistant epilepsy. DEVELOPMENT: Evaluation of a patient with drug-resistant epilepsy requires three steps: first a careful, detailed clinical history to establish the semiological data of the seizure, determine the factors predisposing to drug-resistance (partial epilepsy, history of severe head injury etc.) and to evaluate the antiepileptic treatment given previously and whether the patient actually took the drugs prescribed. Second, a prolonged video-EEG recording is made to determine the type and site of the seizure and decide whether surgical treatment would be suitable. Thirdly, whether structural imaging investigations (magnetic resonance) or functional imaging (sole photon emission computerized tomography or positron emission tomography) should be done. It is also useful to make neuropsychological and psychiatric studies to detect possible associated defects and preexisting psychiatric pathology--which is very common in this population--in order to establish a rehabilitation programme according to the needs of each patient. CONCLUSION: Careful evaluation of each patient with drug-resistant crises leads to the correct diagnosis of epilepsy with the possibility of its correct classification and localization and may permit improvement or change of the treatment received.

Anticonvulsants↗
PubMedDate not supplied

[Open study with tiagabine in partial epilepsy].

OBJECTIVE: Observational studies are necessary for evaluation of the efficacy and safety of the new anti-epileptic drugs. Unlike blind, randomised studies, observational studies are carried out in populations of less resistant patients in normal clinical practice. Therefore these trials give valuable information regarding the efficacy and safety of anti-epileptic drugs. PATIENTS AND METHODS: A multicentre trial was carried out in Spain in which patients with partial epilepsy treated with one or more anti-epileptic drugs were also given tiagabine. Tiagabine was started at a dose of 5 mg per day and increased weekly by 5 mg until the dose considered suitable or a maximum of 70 mg per day was reached. Data were collected on the aetiology of the seizures, their frequency and type and the presence of side-effects. The study was planned to take place over one year, but this paper is being written after six months follow-up. RESULTS: We studied 645 patients with an average age of 35.4 years. The average duration of their epilepsy was 18.3 years and 76.6% of patients had previously received three or more anti-epileptic drugs. The average dose of tiagabine reached during the maintenance period was 32.6 mg/day. After six months of treatment 29.4% of the patients had had no seizures during the last three months of the trial and 67% of the population had a reduction in seizures of over 50%. Some form of side-effect was seen in 52.4% of the patients during the study period. The commonest of these was somnolence (28.2% of the patients) but fainting (23.4%) and difficulty in paying attention/concentration were seen less frequently (15%). In most cases the side-effects were transient or slight (tolerable). No patient had non-convulsive illness. During the study tiagabine was stopped in 166 patients (25.7% of the total) due to lack of efficacy or intolerance. CONCLUSION: Tiagabine is effective, well tolerated add-on therapy in patients with partial epilepsy.

Adolescent↗
PubMedDate not supplied

[Analysis of cost minimization of monotherapy antiepileptic treatment in patients with recent diagnosed epilepsy : the situation in Spain].

OBJECTIVE: To analyze the cost of monotherapeutic treatment of patients with newly diagnosed epilepsy. PATIENTS AND METHODS: We analysed the cost of treatment with lamotrigine (LTG), carbamazepine (CBZ), phenytoin (PHT) and valproic acid (VPA) using published data regarding the efficacy and tolerability of comparative clinical trials of monotherapy. We established a model of treatment for newly diagnosed patients during the first 12 months after diagnosis. A panel of doctors reached a consensus on the use of resources, costs and model of treatment in Spain. We made a cost minimization analysis for economic assessment of the data based on the fact that randomized trials indicated that CBZ, LTG, PHT and VPA ware of similar efficacy. Analysis was done as 'intention to treat'. Only direct medical costs were considered. RESULTS: In Spain treatment with LTG is twice or three times as expensive as treatment with the other drugs. Sensitivity analysis showed that variations in the interval of use of resources and of costs (defined by the panel of doctors) did not significantly alter the results. CONCLUSIONS: Treatment with LTG is more expensive than treatment with the classical drugs. In view of the methodological limitations of this study, further analysis is necessary, particularly of the methodology of cost-benefit, to evaluate the economic impact of the new antiepileptic drugs and determine whether their use is justified as drugs of first choice.

Anticonvulsants↗
PubMedDate not supplied

[An open study of tiagabine in partial epilepsy].

OBJECTIVE: To make an open assessment of the efficacy and tolerance of tiagabine in a population of patients with drug resistant partial seizures. PATIENTS AND METHODS: We did an open multicentric study, in Spain, in which patients with partial epilepsy treated with one or more drugs were also given tiagabine. The main objective of the study was to determine the initial dose and titration of the drug and secondly to evaluate its efficacy and safety. We recorded data on the etiology of the seizures, their frequency and type and the occurrence of adverse effects. The study took place over a period of one year during which there were five appointments for consultation (after six weeks, three months, six months, nine months and one year). RESULTS: We initially included 1,010 patients of which 941 fulfilled the selection criteria. The average age was 32.2 years. The aetiology was symptomatic in 45%. 61.7% of the patients had had previous treatment with three or more anti epileptic drugs. The doses were changed at a rate of 5mg/day per week. The average dose of tiagabine reached during the maintenance phase was 34mg/day. 9.9% of the patients who were followed up for one year (426) had no seizures after the second consultation (when the maintenance dose of tiagabine was reached). 35% of those who came to their final consultation appointment had had no seizures in the previous three months. 81.7% of the patients followed up for a year had an overall reduction in the number of seizures of over 50% between the first and last consultations. An over 50% reduction in seizures was seen in both those of 12 25 years and the 26 65 years old (75% and 73.1% respectively) whilst 86.7% of the patients aged over 65 years also had this degree of improvement. 48.5% of the patients had some type of adverse effect during the study. Somnolence was the commonest side effect (28.2% of the patients), followed by dizziness (21.5%). In most cases the adverse effects were transient or mild (tolerable). During the study 104 patients had their treatment with tiagabine stopped (11.1%) for intolerance and 113 patients (12%) because it was ineffective. No patient had non convulsive status epilepticus. CONCLUSION: Tiagabine is an effective, well tolerated drug when used as additional treatment in patients with partial epilepsy.

Adolescent↗
PubMedDate not supplied

[Drug resistant partial seizures. therapeutic strategies in adults].

INTRODUCTION: Epilepsy affects 6.6 of every 1,000 inhabitants of the developed world. A third of these patients do not achieve satisfactory control of their condition with currently available antiepileptic drugs. Medical treatment of drug resistant epilepsy is complicated owing to the need to evaluate the clinical progress of the different types of epilepsy and to deal with many antiepileptic drugs. DEVELOPMENT AND CONCLUSIONS: We review the basic principles of satisfactory treatment of a patient with drug resistant epilepsy. We particularly emphasize the use of the new antiepileptic drugs, and evaluation of their efficacy and side effects. We also analyze the use of additional treatment of these patients and assess the pharmacokinetic and pharmacodynamic interactions of the drugs which are essential to determine which is the drug of choice in a particular patient. Finally, we consider the most suitable strategies for correct treatment of a patient with epilepsy which is difficult to control.

Adult↗
PubMedDate not supplied

[Titration and dosage of gabapentin].

INTRODUCTION: Gabapentin (GBP) is a new anti epileptic drug which is indicated in partial epilepsy as either monotherapy or additional therapy. Unlike most anti epileptic drugs, GBP can be rapidly titrated. DEVELOPMENT: A recent double blind trial has shown that treatment with GBP may start with 900mg from the first day (300 mg every 8 hours). This dose is sufficient to be effective as monotherapy in patients with partial epilepsy of recent onset. It is also known that in patients with drug resistant epilepsy high doses of anti epileptic drugs are often necessary. In the clinical trials carried out before gabapentin was put on the market, the doses used were generally low (almost always below 1,800 mg/day). However, recent experience has shown that doses of up to 4,800 mg/day markedly increase the efficacy without significant increase in the rate of adverse effects. CONCLUSIONS: Recent data suggest that GBP may be rapidly titrated and high doses of GBP show greater efficacy with no increase in adverse effects, so they are advisable in drug resistant patients.

Acetates↗
PubMedDate not supplied

[Is drug resistant partial epilepsy progressive?].

OBJECTIVES: Approximately one third of the patients with epilepsy are drug resistant. For decades it has been speculated whether repetition of the seizures might potentially lead to progression of the disorder. DEVELOPMENT: In recent years four levels of evidence (experimental, imaging, epidemiological and neuropsychological) suggest that in at least some types of epilepsy the disorder may progress. In various experimental models of epilepsy it has been shown that the persistence of seizures led to biochemical, structural and cellular changes which are persistent and progressive. However, it is difficult to extrapolate these results to human epilepsy. Studies using magnetic resonance volume measurements and spectroscopy have shown that in temporal lobe epilepsy the lesion seems to progress over the years. However, epidemiological and clinical studies do not consistently show a worsening pattern of seizures over the years of epilepsy duration. In fact, recent evidence has shown that drug resistance may occur from the beginning of the disorder. CONCLUSIONS: Neuropsychological studies in patients with drug resistant epilepsy, especially in those with mesial temporal lobe epilepsy, show deterioration of certain cognitive aspects (mainly memory) in relation to the duration and frequency of the partial and secondarily generalized seizures. In case progression of a epilepsy syndrome might be anticipated, this would undoubtedly lead to relevant consequences. If this is so, the therapeutic approach should be more aggressive than at present and might offer early curative treatment, such as epilepsy surgery or neuroprotective drugs, which might halt the progress of the disorder.

Anticonvulsants↗