Optimized method of estimation of critical flicker frequency (CFF).

Overview

The threshold frequency for perception of a flickering light (CFF) is an indicator of arousal of the cerebral cortex, and widely used both for clinical and research purposes [1]. The measurement is often based on the method of limits (MOL), presenting a flickering stimulus of steadily increasing or decreasing frequency. This method is not free from biases [2]. The method of constant stimuli (MCS) is more precise but may take more time, so the state of the subject cannot be considered as invariable [2]. We describe a time-saving, computer-controlled method based on MCS modified with feedback from previous responses.