A coded summation method for measuring a visual evoked response

A method for measuring visual evoked potentials (VEP) on humans at work is reported. The work consists of keying from a keyboard a character that is flashed on a screen, and a light stimulus evokes the visual response. There are two problems in this approach. One is that the energy of the light stimulus is less than that of the flash on the screen. The other is that the performance of work produces noise in the EEG. The coded summation method (CSM) is used to overcome these problems. The effectiveness of the CSM is evaluated. It is concluded that the CSM can measure the VEP in a shorter period of time than the usual averaged summation method, and it has higher reliability in detecting peaks in the EEG.<
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