Fractal Analysis of Eye Movements during Reading

We present a new method for the analysis of reading eye movements based on the methods of nonlinear dynamics. In this preliminary study, the eye movements of normal and abnormal readers were analyzed for evidence of chaotic, nonlinear dynamical behavior. Both power spectral density analysis and fractal dimension determination showed evidence of nonlinearity as manifest in chaotic behavior. The computed fractal dimension of the system's presumed attractor seemed directly related to qualitative assessment of reading ability. Representative subjects did not differ in a similar analysis of pursuit movements. Although fractal analysis did not distinguish unconditionally between normal and abnormal reading in this preliminary study, it nevertheless offers a promising hitherto unused approach to the analysis of eye movements and the modeling of oculomotor behavior.