USO DE POTENCIALES DE ESTADO ESTABLE EVOCADOS VISUALMENTE PARA LA IMPLEMENTACIÓN DE UN SISTEMA DE INTERFAZ CEREBRO COMPUTADOR

Brain Computer Interface (BCI) systems allow direct communication between the computer and the brain; they are an option for interaction from people who has several neuromuscular injury.One of the mayor methodologies for BCI implementation bases its operation in steady state visual evoked potentials (SSVEP), this paradigm consist in show some visual stimulates that have an oscillating light in stables frequencies.The user has to pay attention to the light that correspond to the command that he wants to select, which produces a signal with a high component in the frequency of the stimulate and its multiples in the occipital part of the brain. This signal can be measured by electroencephalography (EEG) equipment and it allows the user’s intention from select one of the commands.In this article we present a first SSVEP based BCI prototype that is proposed like a help system for disabled people, for this purpose, we use a low cost system with dry electrodes, this condition could permit more access for people and low installation time. In this prototype the signal of 8 electrodes from the occipital zone of the brain are processed with the Minimum Energy Combination (MEC) methodology; it was probed in an volunteer adult of 37 years old who reached an accuracy of 87% in identifying five visual stimulates with an average time of 4.5seg for detecting a command and he reached an Information Transfer Rate (ITR) of 20bits per minute.