Evaluación funcional de la vía visual aferente mediante potenciales evocados visuales multifocales en el Síndrome Radiológico Aislado

Resumo

Radiologically Isolated Syndrome represents an early and preclinical form of Multiple Sclerosis that is currently not sufficiently characterized. The study of the afferent visual pathway through innovative electrophysiological tests, such as the multifocal Visual Evoked Potentials, can allow us to objectively identify early functional changes in the visual pathway. This is the first study in patients with Radiologically Isolated Syndrome in whom the functional status of the visual afferent pathway has been evaluated using the multifocal Visual Evoked Potentials. The results of this work are certainly relevant given the current interest in understanding the pathophysiological mechanisms associated with demyelinating lesions in the early stages of Multiple Sclerosis. Our results suggest that neuroaxonal damage in the visual afferent pathway is present in the early asymptomatic stages of Multiple Sclerosis. This clinical, observational, longitudinal and prospective study has included 21 patients with Radiologically Isolated Syndrome. All patients underwent the usual protocol for diagnosis and follow-up of demyelinating pathologies and diagnostic tests with the multifocal Visual Evoked Potentials, Optical Coherence Tomography and Automated Static Perimetry, as well as an ophthalmological examination. At 24 months of follow-up, 23,8% of our patients with Radiologically Isolated Syndrome converted to Clinically Isolated Syndrome or Multiple Sclerosis. In our study, decreased amplitudes and delayed latencies of the multifocal Visual Evoked Potential responses in patients with Radiologically Isolated Syndrome were significantly associated with a higher risk of conversion to Clinically Isolated Syndrome or Multiple Sclerosis at two years of follow-up. The alterations in the amplitudes and latencies of the responses of the multifocal Visual Evoked Potentials observed in Radiological Isolated Syndrome indicate that the visual afferent pathway is frequently and early affected in the preclinical stages of Multiple Sclerosis, suggesting that the multifocal Visual Evoked Potentials can become an especially useful tool in the clinic for the diagnosis and objective monitoring of demyelinating processes in their early stages.