Fractal dimension based neurofeedback training to improve cognitive abilities

Currently, neurofeedback training can be used not only to treat the patients with attention deficit hyperactivity disorder, learning difficulties, etc. but also to improve cognitive abilities of healthy people. Training protocols based on alpha, theta, or theta/beta power calculated from Electroencephalogram (EEG) are commonly used in the neurofeedback training. However, when the standard neurofeedback protocols are used, the EEG recording is required before the training to obtain the training threshold for each subject. In this paper, we propose a fractal dimension (FD)-based neurofeedback training protocol with adaptive algorithm, which does not need any before-training recording. The algorithm is integrated in the Shooting game. The efficiency of the FD-based neurofeedback training in comparison with traditional individual theta/beta based neurofeedback training is assessed using Psychology Experiment Building Language (PEBL) tests such as matrix rotation (for spatial ability), change detection (for focused attention), math processing (for cognitive abilities) and test of attentional vigilance (for attention of vigilance). 40 subjects participated in the study. They were divided randomly into FD-based neurofeedback training group and theta/beta ratio-based training group. The results show that after neurofeedback training participants from FD-based training group has similar or better test performance than the one from ratio-based group.