Single Neurofeedback Session (Based on IAF) Effect on Resting State EEG Spectral Characteristics and Effectiveness of Alternative Uses Task Performance

The study is dedicated to the investigation of EEG spectral characteristics during resting states and a creative task performance (Alternative Uses Task, AUT) before and after a single session of neurofeedback (NFB) and sham-NFB training. The study involved 24 adolescents (aged 15–17 years) who were randomly divided into two independent groups both with 12 subjects. The test group (TEST) participated in one session of NFB training based on their own EEG data (power of individual alpha frequency), while the control group (SHAM) participated in one session of sham-NFB training. Spectral power in the Δ (1.5–4 Hz)-, θ (4–8 Hz)-, α1 (8–10 Hz)-, α2 (10–13 Hz)-, β1 (13–18 Hz)-, β2 (18–30 Hz)-bands of the EEG during eyes open and closed resting states, and event-related synchronisation/desynchronisation of the EEG during performance of the alternative use task before and after the NFB/SHAM session were analysed. Prior to the NFB/SHAM sessions, no differences were observed between the groups in the resting state EEG. After the NFB/SHAM session, lower EEG power values in the β2-band were observed in the test group compared to the control group in the eyes-closed condition. There was a decrease in Δ-band EEG power in frontal temporal regions in the eyes-closed condition and an increase in α2-band power in the eyes-open condition after the NFB session compared to a condition before the NFB session. In the control group, no differences in EEG spectral power were observed in the states AFTER vs. BEFORE the SHAM session. Analysis of event-related EEG synchronisation/desynchronisation during the AUT before and after the NFB session revealed no differences between the test and control groups. Intragroup comparisons of AFTER vs. BEFORE NFB/SHAM sessions revealed the following different effects: in the test group, first, EEG desynchronisation in the frequency range 17.5–30 Hz was observed in the frontal regions of the left hemisphere in the interval 220–300 ms after the presentation of the stimulus, and subsequently, there was synchronisation in the θ and low-frequency α electroencephalogram (EEG) ranges (4–9.8 Hz) (in the interval 540–1400 ms) with maximum differences in the frontal regions. The control group was characterised by synchronisation of electroencephalogram (EEG) activity in the higher frequency ranges of 9.5–26 Hz and in the narrower time interval of 520–760 ms in central and frontal electrodes. Consequently, a single NFB session in the test group resulted in changes in EEG spectral power during resting states that were not observed in the control (SHAM) group following sham training, and exhibited precise modulation of the state during creative activity.