EEG neurofeedback: A brief overview and an example of peak alpha frequency training for cognitive enhancement in the elderly.
Angelakis, E., Stathopoulou, S., Frymiare, J. L., Green, D. L., Lubar, J. F., & Kounios, J. (2007). Clinical Neuropsychology, 21(1), 110129.
Neurofeedback is a technique that uses electroencephalographic (EEG) biofeedback to train individuals to alter their brain activity through operant conditioning.
Production of the target EEG activity results in a sensory reward, such as the audio and visual reward of playing a movie, while deviation from it produces the withholding of reward, such as the dimming of the movie screen and reduction of auditory volume.
Current research indicates the potential of neurofeedback to contribute to cognitive enhancement in the elderly.
The EEG is produced by synchronous activity from thousands to millions of neurons, which is typically recorded at the scalp, amplified, digitized, and plotted.
The raw EEG signal then appears as an oscillatory pattern, which can be filtered to identify narrow frequency bands that reflect specific brain sources and functions.
Increasing alpha (8-13 Hz) and theta (4-7 Hz) magnitude has been used as an effective treatment for alcoholism.
Posterior alpha activity is associated with relaxed consciousness, while alpha “blocking” is associated with alertness and active processing.
Alpha feedback can also be used to reduce or increase anxiety, with increased alpha correlated with decreased anxiety and vice versa.
The alpha rhythm, which falls in the range of 8-13 Hz with an average peak of 10-11 Hz in healthy adults, is a particular EEG phenomenon of interest.
Peak alpha frequency (PAF) corresponds to the frequency with the highest magnitude within this alpha range.
The frequency of this oscillation has been positively correlated with mental performance at all ages, both in healthy individuals and individuals with neurological conditions.
The study conducted by Angelakis et al. investigated whether training elderly individuals to increase their PAF to the levels of younger people would result in improved cognitive performance.
In the experiment, participants were assigned to either the PAF neurofeedback protocol, which withheld reward if alpha magnitude increased, or the alpha magnitude neurofeedback protocol, which withheld reward if PAF increased.
Those assigned to the PAF protocol demonstrated general improvement in the speed of processing and executive function.
The alpha magnitude protocol elicited improvement in memory, but decreased the performance in the cognitive areas amplified by the PAF neurofeedback protocol.
This suggests that PAF neurofeedback and alpha amplitude neurofeedback improve specific, mutually exclusive areas of cognitive function.
Though certainly an incomplete solution to cognitive decline with age, further studies exploring the relationship between EEG and mental function show promise for the treatment of mental conditions previously unaddressed.
Valdez, M. (1985). Biofeedback & Self-Regulation, 10(4), 315–324.
Biofeedback-assisted training can be partnered with open focus (an achieved state of attention which is all inclusive and integrates all modes of the sensory experience: sight, smell, taste, thoughts, feelings, emotions, body, space, volume and void) attention training in order to reduce stress levels.
In biofeedback-assisted training, sensitive instruments are used to measure body processes and conditions typically beyond our awareness.
These measurements are subsequently converted into visual, auditory, or tactile signals which the individual can sense – thus bringing these body processes and conditions into his or her awareness so that they can be controlled.
In a 1982 study conducted at Baruch College, the effects of open focus attention training and biofeedback training on academic performance, stress-related symptoms, and physiological measures was investigated in undergraduate students.
A series of open-focus attention-training workshops were offered with the intention of improving concentration, increasing attention span, lessening anxiety, and equipping students with techniques to cope with the stressors in their academic and personal lives.
Students who attended these workshops, completed training on their own time, and received biofeedback training (experimental group) were compared with students who received no stress reduction training at all (control group). GPA was used as a measure of academic performance and responses on the Stress Level Assessment (SLA) were used as a measure of stress.
The form covers several categories of stress including anger, anxiety, cardiovascular or respiratory problems, eating problems, emotional problems, muscle tension, and sleeping problems.
These variables were recorded at the beginning of the study and after the 9-week training period.
The GPAs of the experimental group differed significantly from those of the control group, giving some indication that reduced stress levels are associated with improved academic performance.
The students who did not receive training actually exhibited a drop in GPA, which might indicate that students under stress who are not treated are potential failures at school.
This association, however, requires further research in order to be confirmed.
The experimental group also showed significantly greater improvement in stress levels according to the SLA form results.
Experimental subjects who received biofeedback training also differed significantly from the control group in each modality in which the subjects were trained – Thermal, EMG, EEG, and GSR. These findings have increased expectations regarding the success of the attention-training program in reducing student stress levels.
Overall, the study demonstrates the high potential of open focus attention training and biofeedback training to reduce student stress levels and improve academic performance.
Learned self-regulation of EEG frequency components affects attention and event-related brain potentials in humans.
Egner, T., & Gruzelier, J. H. (2001). NeuroReport, 12, 4155–4159.
In this study, a group of healthy individuals were trained on protocols of SMR and beta 1 enhancement. A go/no-go sustained attention test was applied as a behavioral measure of attention.
Post-neurofeedback outcome measures in ADD/ADHD samples have typically shown improvement in performance of sustained attention go/no-go continuous performance tasks (CPT), reflecting an increased overall efficacy of stimulus detection, evaluation, and subsequent selection and execution of the appropriate behavioral response.
Following the protocols, the healthy participants exhibited overall improved attentional performance.
Their performance on a sustained attention CPT was significantly improved on measures of impulsiveness and perceptual sensitivity.
The study also identified a positive correlation between SMR enhancement and attention improvement and an inverse relationship for learned beta1 enhancement.
S. Kober, D. Schweiger, M. Witte, J. Louise Reichert, P. Grieshofer, C. Neuper and G. Wood (2015). Journal of Neuroengineering and Rehabilitation
This experiment was designed to see what effects neurofeedback would have on the memory of stroke patients. Strokes can significantly impact memory, and while memory has been shown to spontaneously come back, that is not a guarantee for everyone.
Therefore, there is a push to see what techniques are best for restoring as much memory as possible.
The subject pool was made up of 24 stroke patients that didn’t have any other major neurological or psychiatric disorder (dementia, depression, aphasia, etc) and 40 healthy controls.
They all underwent a pre-assessment, then underwent neurfofeedback training specific to the location of their lesions for 3-4 weeks, and finally did a post-assessment once the neurofeedback training was complete.
Both the stroke and control groups were found to be able to modulate their brain activity during the neurofeedback sessions.
All of the different types of neurofeedback trainings showed a significant increase in memory assessment test scores of unique areas (for example, SMR had increases in long term memory and verbal short term while upper alpha had increases in verbal long-term, verbal short term and memory span).
The healthy controls also showed statistically significant increases in their assessment test scores. Overall, this supports the idea that neurofeedback is useful for memory improvements in stroke patients, as well as normal people.
Valentia Lavermicocca (2015)
This study examined the effects of neurofeedback on the cognitive performance of Parkinson’s Disease (PD) patients. Twenty patients were recruited and split into two groups of ten: experimental group (neurofeedback training) and control group (conventional cognitive training).
Both groups underwent 2 sessions per week for three months (24 total session for 40 minutes each). They had cognitive assessments (troop test, trail making test, RAVLT, phonemic verbal fluency test, frontal assessment battery, and ARCES) done before treatment to establish baseline, the right after treatment and finally four months after treatment.
They found statistically significant improvement in all categories with both the neurofeedback group and the conventional cognitive training groups, when comparing immediately post-treatment scores to baseline scores.
However, this improvement wasn’t maintained at the four month mark. This was expected though due to the degenerative nature of the disease.
These results suggest that neurofeedback is a viable option for improving the cognitive skills of PD. However, it is not a cure for the disease; it does not change the long-term outcome, just delays it.
Benedikt Zoefel, René J. Huster and Christoph S. Herrmann
This study examined at the effect of EEG neurofeedback on cognitive performance by specifically looking at the upper alpha band.
The amplitude of the upper alpha band has been positively correlated with performance on mental rotation tests. The study consisted of 22 participants with 12 in the experimental group that underwent neurofeedback training and 10 in the control group that did not have any training.
The participants in the experimental group underwent five training sessions within one week, and cognitive ability was measured using mental rotation tasks on the first and last training day for both groups; however, those in the control group did not undergo training for the second, third, and fourth sessions.
The performance of the neurofeedback group on the mental rotation task significantly improved after the five training sessions compared to their baseline, which was taken on the first day.
The control group, however, did not have any significant improvements in performance on this task from the baseline measurement.
Similarly, the neurofeedback group had an increase in the amplitude of the upper alpha band after the neurofeedback training, while the control group did not.
For the experimental group, the increase in the amplitude of the upper alpha band was linear throughout the week of training sessions, suggesting that neurofeedback training builds on previous training.
R. Rozengurt, L. Shtoots, A. Sheriff, O. Sadka and D. Levy (2017). Neurobiology of Learning and Memory
This study examined the effect of neurofeedback training focused on theta enhancement on improving new memory consolidation.
Theta oscillations in the hippocampus are important for the formation and retrieval of memories.
75 subjects were assigned to either the neurofeedback theta group, the active control (neurofeedback low beta) group, or the passive control (watching a neutral nature movie) group.
The participants took three recall tests and then had one session in their assigned group.
After the session, the participants took additional recall tests after the assigned training session, 24 hours after the session, and one week after training to assess the effect of neurofeedback on episodic memory consolidation and stability.
The up-regulation of theta through the neurofeedback training had significantly greater improvements in episodic memory than the passive and active control groups. This result was seen in all three post-intervention recall tests.