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Title:Stimulus intensity effects on the steady-state visual evoked potential
Author(s):Yen, Sean Wayne
Department / Program:Electrical & Computer Eng
Discipline:Electrical & Computer Engr
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:M.S.
Genre:Thesis
Subject(s):steady-state visual evoked potential (SSVEP)
stimulus intensity
brain-computer interfaces
brain-computer interfaces (BCIs)
electroencephalography (EEG)
Abstract:This research tests the hypothesis that the amplitude of the steady-state visual evoked potential (SSVEP), a neural response to repetitive visual stimuli, is positively correlated with stimulus intensity. SSVEPs are often used as input mechanisms for brain-computer interfaces (BCIs), systems that establish a direct communication channel between human brains and computers. User performance with SSVEP-based BCIs is dependent on the amplitude of the SSVEP response, which has been shown to be affected by stimulus parameters. In particular, previous results have shown that the SSVEP amplitude is positively correlated with parameters such as stimulus contrast, size, and viewing distance. These stimulus parameters are related to stimulus intensity, the total amount of light emitted by the stimuli, which suggests that SSVEP amplitude is also positively correlated with stimulus intensity. Such a relationship is often accepted in SSVEP-based BCI literature, but has yet to be experimentally verified. In this study, ten subjects were presented with flickering stimuli at eleven stimulus intensities. The stimuli flickered at a frequency of 7 Hz and were presented at a fixed distance using an LED panel. The SSVEP response was recorded using electroencephalography and analyzed using Fourier and canonical correlation analyses, which are both commonly used in SSVEP-based BCI systems. The results of this study show a significant positive correlation (R=0.173,p=9.122*10^(-7)) between stimulus intensity and the amplitude of the SSVEP response for the measured stimulus intensities.
Issue Date:2015-04-22
Type:Thesis
URI:http://hdl.handle.net/2142/78410
Rights Information:Copyright 2015 Sean Yen
Date Available in IDEALS:2015-07-22
Date Deposited:May 2015


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