Relationship between vigilance levels and characteristics of saccadic eye movement

The purpose of this study was to investigate the possibility for evaluating vigilance levels using a parameter of saccadic eye movement. EEG was measured and analyzed by means of fast Fourier transform, and the spectral power of /spl alpha/ and /spl beta/ wave bands were obtained so as to extract [/spl beta/]/[/spl alpha/+/spl beta/] which was assumed to reflect vigilance levels. Eye movement was measured so as to calculate saccadic peak velocity (SPV) and relative SPV (RSPV) which was normalized by the mean SPV at the corresponding amplitude of saccade. The relationship between [/spl beta/]/[/spl alpha/+/spl beta/] and RSPV was investigated and it revealed that RSPV decreased according to the decline in the vigilance level. This indicates the possibility for evaluating vigilance levels using RSPV.