Rapid Acquisition of the Stimulus Response Relationship using Visual Evoked Potentials

Abstract

The flash visual evoked potential (FVEP) is an electrical potential recorded with electroencephalogram (EEG) at the occipital cortex. Current FVEP assessment may be elaborated with the acquisition of stimulus response (SR) relation of the visual system. A drawback of this adjustment is the time required for data acquisition. This study aimed to develop an optimal (rapid) stimulus paradigm for assessing the SR relationship using FVEP.SR relationships were obtained using two different protocols in eight healthy participants; one considered 100 stimuli for 10 different intensity levels (standard technique), the other considered 1000 stimuli of varying intensity levels within a fixed intensity range (novel technique). Hypothetically the novel technique produces a similar SR relationship but requiring reduced number of stimuli. However, the present study did not find a significant intensity dependency on the FVEP. Consequently, no mathematical model for the SR relation was fit to the data, and exploration of the novel technique was excluded. Instead, the present study investigated the minimal number of stimuli required to acquire a representative FVEP component. Secondly, the potential change of FVEP components during the experiment was investigated. This study demonstrates that it is possible to acquire a reliable FVEP component with on average 54 stimuli (gross mean (39) + 1 SD (14)), independent of stimulus intensity. Additionally, this study demonstrated that the FVEP components change significantly (p<0.05) for most stimulus intensities when 1000 or more flashes are used; amplitudes increased with time for low intensity stimulation, while amplitudes reduced with time for high intensity stimulation. Although the present study did not find an intensity dependency of the FVEP component, it demonstrated that stimulation time is an important parameter when acquiring SR relationships using FVEP. The stimulation time certainly influenced the SR relationship calculated in the present study. Further studies can and should reduce the number of stimuli to produce a representative SR relationship using FVEP.