Relation of Structural and Functional Changes in Auditory and Visual Pathways after Temporal Lobe Epilepsy Surgery.

Auditory and visual pathways may be affected as a consequence of temporal lobe epilepsy surgery because of their anatomical relationships with this structure. The purpose of this paper is to correlate the results of the auditory and visual evoked responses with the parameters of tractography of the visual pathway, and with the state of connectivity between respective thalamic nuclei and primary cortices in both systems after the surgical resection of the epileptogenic zone in drug-resistant epileptic patients. Tractography of visual pathway and anatomical connectivity of auditory and visual thalamus-cortical radiations were evaluated in a sample of eight patients. In general, there was a positive relationship of middle latency response (MLR) latency and length of resection, while a negative correlation was found between MLR latency and the anatomical connection strength and anatomical connection probability of the auditory radiations. In the visual pathway, significant differences between sides were found with respect to the number and length of tracts, which was lower in the operated one. Anatomical connectivity variables and perimetry (visual field defect index) were particularly correlated with the latency of P100 wave which was obtained by quadrant stimulation. These results demonstrate an indirect functional modification of the auditory pathway and a direct traumatic lesion of the visual pathway after anterior temporal lobectomy in patients with drug resistant epilepsy.

Consentimiento informado en pacientes con epilepsias intratables / Informed consent in patients with intractable epilepsy

La ética médica aborda, entre otros aspectos, la relación médico-paciente, de la cual se deriva el término consentimiento informado como su máxima expresión. La epilepsia afecta al 1-2 por ciento de la población mundial, y en la búsqueda de soluciones a esta enfermedad los sujetos son involucrados en diferentes tipos de estudios. En el presente trabajo se realiza una breve revisión de algunos aspectos éticos relacionados con la aprobación dada por los pacientes que padecen epilepsia o su representante legal para participar en estudios que presuponen la realización de exámenes diagnósticos y el empleo de formas novedosas de tratamiento, lo que se materializa a través del consentimiento informado. Especialmente, se hace referencia a la participación de los pacientes en ensayos clínicos y el manejo de las pacientes que quedan embarazadas en el transcurso del ensayo clínico, los efectos adversos de la medicación y de la cirugía de epilepsia(AU)

Medical Ethics addresses, among other aspects, the doctor-patient relationship from which the term informed consent is derived as its maximum expression. Epilepsy affects 1-2 percent of the world population, and in the search for solutions to this disease the subjects are involved in different types of studies. In the present paper, a brief review of some ethical aspects related to the approval given by patients suffering from epilepsy or their legal representative to participate in studies that presuppose the performance of diagnostic tests and the use of novel forms of treatment. This is materialized through informed consent. Especially, there is a reference to the participation of patients in clinical trials, and the management of patients who become pregnant during the clinical trial, the adverse effects of medication, and epilepsy surgery(AU)

Temporal lobe epilepsy surgery modulates the activity of auditory pathway.

The purpose of this paper is to evaluate the effects of the anterior temporal lobectomy on the functional state of the auditory pathway in a group of drug-resistant epileptic patients, linking the electrophysiological results to the resection magnitude. Twenty-seven patients with temporal lobe epilepsy and a matched control group were studied. Auditory brainstem and middle latency responses (ABR and MLR respectively) were carried out before and after 6, 12 and 24 months surgical treatment. The volume and longitude of temporo-mesial resected structures were estimated on magnetic resonance images taken 6 months after surgery. Before the intervention the patients showed a significant delay of latency in waves III, V, Pa and Nb, with an increase in duration of I-V interval in comparison with healthy subjects (Mann-Whitney U-test, p<0.05). After resection, additional significant differences in waves I and Na latency were observed. Na and Pa waveforms showed a tendency to increase in amplitude, which became statistically significant 12 months after surgery for right hemisphere lobectomized patients in the midline electrode, and in Pa waveform for all patients in the temporal electrodes ipsilateral to resection (Wilcoxon test, p<0.05). In general, latency variations of MLR correlated with resection longitude, while changes in amplitude correlated with the volume of the resection in the middle temporal pole and amygdala (Pearson' correlation test, p<0.05). As a result, we assume that anterior temporal lobectomy provokes functional modifications into the auditory pathway, probably related to an indirect modulation of its activity by the temporo-mesial removed structures.