Motion sensitivity assessment based on an analysis of the spatio-temporal features of eye movements

Motion sensitivity refers to the individual’s ability to detect and perceive motion in the environment. It is a fundamental property of visual perception, crucial for orientation and navigation in the environment. Yet, its behavioral assessment is usually tedious and time-consuming, limiting assessment in clinical and rehabilitation contexts. Assessment of eye-movements may provide a more observer-friendly way to obtain the same information. For this reason, in this study, we evaluated the suitability of an eye-movement-based method to assess various aspects of motion sensitivity. To do so, we quantify the spatio-temporal features of eye-movements made during a smooth pursuit task at different velocities. We found that the temporal and spatial uncertainties robustly reflected the changes in stimulus speed. Furthermore, we measured motion sensitivity using a conventional random dot kinematogram-based direction discrimination task. We found that none of the spatio-temporal features computed from the tracking task were correlated with the psychophysical motion sensitivity measures (slope and threshold) obtained with the random dot kinematogram. We conclude that continuous visual tracking efficiently assesses specific aspects of motion processing in an observer-friendly manner. Moreover, the approach provides information that is complementary to that obtained through conventional psychophysical tests such as the random dot kinematogram.