Steady-State Visual Evoked Potential Response - Impact of the Time Segment Length

I. Volosyak, H. Cecotti, and A. Gräser (Germany)

Keywords

Brain-Computer Interface (BCI), Electroencephalogram(EEG), Steady State Visual Evoked Potential (SSVEP),Signal Detection

Abstract

When a visual stimulus with a constant frequency is presented to a person, it is possible to observe a continuous brain response in the visual cortical area. This response is called a steady-state visual evoked potential (SSVEP). The detection of this brain response can be analyzed as a command for tailoring a Brain-Computer interface (BCI). Its goal is to provide a new output channel for the brain that requires voluntary control. The efficiency of a BCI depends on the commands accuracy and their latency: the time between the order from the subject and the moment when the command is detected. Given one particular SSVEP response classification method, the BCI control is variable among the users. This variance is translated into different performance between subjects. We propose a robust classification method of SSVEP responses, which does not require any training. A performance comparison on 8 different time segment lengths over 10 subjects is proposed. The average time segment length for obtaining a SSVEP response recognition of 95% is determined to be 2.8s.

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