The applications and efficacy of Neurofeedback and Biofeedback treatment modalities are consistently being researched. There are over 1400 peer-reviewed studies published and this number is growing daily. Below is an extremely small sample of some of the research involving Neurofeedback. These articles are milestones for research in Neurofeedback and establish Neurofeedback as an evidence-based treatment modality. The following are a few summaries of Neurofeedback research abstracts with potential implications for Neurofeedback training.
fMRI stands for Functional Magnetic Resonance Imaging, and is an imaging technique that measures brain activity by detecting changes in blood flow in the brain. The studies in this section demonstrate that Neurofeedback may help to facilitate structural changes in the brain, which may lead to improvements in symptoms.
Ghaziri, J., Tucholka, A., Larue, V., Blanchette-Sylvestre, M., Reyburn, G., Gilbert, G., . . . Beauregard, M. (2013). Neurofeedback Training Induces Changes in White and Gray Matter. Clinical EEG and Neuroscience, 44(4), 265-272. doi:10.1177/1550059413476031
In this study, Health university students were randomly assigned to the experimental group, sham group or control group. Participants in the experimental group trained to enhance beta waves at F4 and P4. Attentional performance and MRI data were recorded one week before training and one week after training. Higher scores on auditory and visual sustained attention were present in experiment group. Gray matter volume increases were detected in cerebral structures involved in this type of attention. This study constitutes the first empirical demonstration that neurofeedback training leads to microstructural changes in white and gray matter.
Beauregard, M., & Lévesque, J. (2006). Functional Magnetic Resonance Imaging Investigation of the Effects of Neurofeedback Training on the Neural Basis of Selective Attention and Response Inhibition in Children with Attention-Deficit/Hyperactivity Disorder. Applied Psychophysiology and Biofeedback, 31(1), 3-20. doi:10.1007/s10484-006-9001-y
Two fMRI experiments were conducted to measure the effects of neurofeedback training (NFT) in ADHD children on neural areas of selective attention and response inhibition. 15 children were randomly assigned to the experimental (Neurofeedback) group while five were randomly assigned to the control (CON) group. The experiment group trained to increase Beta (15-18 Hz) and decrease Theta (4-7Hz). The fMRI was conducted one week before beginning NFT and at the end of NFT. Significant activation was seen for the experimental group in areas associated with attention. No changes in activation were seen in the control group. This suggests that NFT can help continually normalize brain systems as well as functional areas associated with selective attention and response inhibition.
Randomized-Controlled Trial Studies
These studies require the participants to be randomly selected for either the treatment group (the group that received Neurofeedback training), the placebo group (the group that thought they received Neurofeedback treatment), and/or the control group (active control: the group that received the standard treatment or inactive control: no treatment at all). Randomized-controlled studies are the highest research standards for clinical studies. The following articles demonstrate how Neurofeedback stands up to these rigorous research standards.
Steiner, N. J., Frenette, E. C., Rene, K. M., Brennan, R. T., & Perrin, E. C. (2014). In-School Neurofeedback Training for ADHD: Sustained Improvements From a Randomized Control Trial. Pediatrics, 133(3), 483-492. doi:10.1542/peds.2013-2059
This study attempted to conduct a randomized control trial in which they evaluated sustained improvements after six months of 40 neurofeedback sessions which occurred in school. Individuals received either neurofeedback or Cognitive Training (CT). Participants were between 7-11 years old with diagnosed ADHD. 104 children were randomly assigned to receive either neurofeedback, CT, or a control condition. Neurofeedback participants maintained significant gains on inattention, executive functioning, and hyperactivity.
Bakhshayesh, A. R., Hänsch, S., Wyschkon, A., Rezai, M. J., & Esser, G. (2011). Neurofeedback in ADHD: A single-blind randomized controlled trial. European Child & Adolescent Psychiatry, 20(9), 481-491. doi:10.1007/s00787-011-0208-y
This study looks at using biofeedback with EEG neurofeedback in a single-blind randomized control trial design to evaluate the efficacy of neurofeedback. EMG biofeedback (BF) and theta/beta ratio reduction training were used in this study. 35 children with ADHD are randomly assigned to either therapy group (18) or control group (17) treatment for both groups utilize 30 sessions. Teachers and parents completed behavior rating scales as well as psychometric measures. Training reduced theta/beta ratios. Parents reported a reduction in ADHD symptoms and inattention. Improvements in NF groups were higher than BF groups. NF groups also improved on psychometric measures; the NF group showed a reduction inattention symptoms and reaction time on neuropsychological tests.
Meisel, V., Servera, M., Garcia-Banda, G., Cardo, E., & Moreno, I. (2013). Neurofeedback and standard pharmacological intervention in ADHD: A randomized controlled trial with six-month follow-up. Biological Psychology,94(1), 12-21. doi:10.1016/j.biopsych.2013.04.015
One of the first studies which utilized a randomized control trial compares Neurofeedback to stimulant medication for the amelioration of ADHD symptoms. In this study, 23 children (11 boys and 12 girls) between the ages of (7-14 years old) were randomly assigned either 40 sessions of theta/beta training or received methylphenidate. They utilized behavioral rating scales completed by parents and educators pre and post treatments. This was tested at both two and six-month follow-ups. Though similar significant reductions were reported in both treatment conditions for both functional and primary ADHD symptoms, only the Neurofeedback group had demonstrated significant academic improvements.
Neurofeedback Efficacy Studies
In terms of research, efficacy looks to define the performance of an intervention in a controlled, research environment. Comparisons are made to other treatment modalities such as certain pharmaceutical interventions. The following studies provide strong evidence for the efficacy of Neurofeedback in a research context.
Monastra, V. J., Monastra, D. M., & George, S. (2002). The effects of stimulant therapy, EEG biofeedback, and parenting style on the primary symptoms of attention-deficit/hyperactivity disorder. Applied Psychophysiology and Biofeedback, 27(4), 231-249. doi:10.1023/a:1021018700609
100 children ages 6-19 who had ADHD, inattentive, or combined participated in this study which aimed to examine the effects of Ritalin, EEG biofeedback, and parenting styles on ADHD symptoms. All patients participated in the 1-year multimodal program that included Ritalin, parent counseling, and academic support at school. 51 of the participants received EEG biofeedback as well. In the post-treatment assessments, individuals were assessed with both stimulant and stimulants. Individual completed T.O.V.A and ADDES scales. Those who had received EEG biofeedback sustained the gains when tested without Ritalin.
Monastra, V. J., Lubar, J. F., Linden, M., Vandeusen, P., Green, G., Wing, W., . . . Fenger, T. N. (1999). Assessing attention-deficit hyperactivity disorder via quantitative electroencephalography: An initial validation study. Neuropsychology, 13(3), 424-433. doi:10.1037//0894-4220.127.116.114
Analysis of EEG output at the prefrontal location (Cz) was conducted on 482 individuals between the ages of 6-30 years old. The study attempted to test that cortical slowing in a prefrontal region can help differentiate patients with attention deficit hyperactivity disorder (ADHD) from nonclinical control groups. Participants were divided into 3 groups (ADHD, Inattentive; ADHD, Combined; and control group) on the basis of results of the standardized clinical interview, behavioral rating scales, and a CPT continuous performance task. Overall, a relation between theta/beta ratios being evaluated in ADHD patients were found.
Arns, M., Heinrich, H., & Strehl, U. (2014). Evaluation of neurofeedback in ADHD: The long and winding road. Biological Psychology, 95, 108-115. doi:10.1016/j.biopsych.2013.11.013
Prevalence is reported to be 3-7 % for ADHD in school age children. Three subtypes: predominantly inattentive, predominantly hyperactive-impulsive and combined type. Core symptoms of ADHD consist of inattention, impulsivity, and hyperactivity. Limitations exist for medication and behavior therapy. Neurofeedback helps teach or improve self-regulation of brain activity. Principles of classical conditioning and operant conditioning can be applied to help individuals gain self-regulatory skills. SMR treatments conducted by Sterman found improvements in sleep quality. Lubar employed A-B-A designs to find that symptoms of ADHD increased when training protocols were reversed. Protocol training, specifically training Theta/Beta (4-8 Hz/13-21 Hz) led to improvements in cognitive measures (attention and IQ). Studies since then have found that Theta/Beta ratio (TBR) training has comparable results to stimulant medication. Semi-active control conditions find that neurofeedback useful for inattention and impulsivity. Randomized control trials find that these effects are consistency at follow-up and a reduction in hyperactivity and impulsivity is also seen. 40 sessions lead to stronger results. Methylphenidate has not been shown to be more effective than neurofeedback in several studies. Low sample sizes may lead to further issues. It is difficult to eliminate all the other effects involved with Neurofeedback, but they can be controlled by using randomization in studies. Studies which randomized trials often fail to utilize proper Neurofeedback and make serious errors in the administration of Neurofeedback. For example utilizing thresholds that are too high. Many randomized studies do not consider the effects of generalization or apply any learning strategies to aid this process. There should be a focus on specific protocol investigation. A multidimensional approach should be taken to work with neurofeedback. Newer modalities of Neurofeedback, LORETA, and sLORETA show increased promise when dealing with complex disorders.