Review Clinical efficacy and potential mechanisms of neurofeedback Sharon Niv ⇑ Department of Psychology (SGM 501), University of Southern California, 3620 S. McClintock Ave., Los Angeles, CA 90089-1061, USA article info Article history: Received 10 August 2012 Received in revised form 20 November 2012 Accepted 30 November 2012 Available online xxxx Keywords: Neurofeedback Psychopathology Alternative treatment Neurotherapy abstract Although many psychological disorders have significant basis in neurobiological dysfunction, most treat- ment approaches either neglect biological aspects of the problem, or approach dysfunction through phar- macological treatment alone, which may expose individuals to negative side effects. In recent decades, neurofeedback has been promoted as an alternative approach to treating neurobiological dysfunction. Neurofeedback helps individuals gain control over subtle brain activity fluctuations through real-time rewards for pre-established target brainwave frequencies at specific cortical locations. This paper reviews the effectiveness of neurofeedback in a range of conditions, including ADHD, autism spectrum disorders, substance use, PTSD, and learning difficulties. Neurofeedback has emerged as superior or equivalent to either alternative or no treatment in many of the examined studies, suggesting it produces some effects worthy of further examination. In light of its potential to address neurobiological dysfunction directly, future research is suggested in order to refine protocols, as well as to establish effectiveness and efficacy. Potential mechanisms of neurofeedback are discussed, including global connectivity, neuroplasticity, and reinforcement of the default mode network, central executive network, and salience network. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Clinicians and researchers have long searched for ways to influ- ence minds toward optimal functioning. However, many methods for influencing brain activity, such as surgery, psychopharmacol- ogy or electroconvulsive therapy, are invasive or produce profound side effects. Talk therapy is often effective, but some conditions re- quire an integrated biological and cognitive approach. Neurofeed- back is an alternative approach that aims to help individuals alter brain activation without introducing electrical or magnetic activity, or pharmacological compounds into the brain, hence pre- venting the brain from becoming dependent on outside influences for better functioning. However, while this approach may be con- ceptually appealing, there have been few rigorous studies to estab- lish its efficacy and effectiveness. This review summarizes different neurofeedback protocols and details efficacy findings in a wide range of conditions. Potential mechanisms of change and direc- tions for future research and clinical practice are also discussed. 1.1. Biofeedback Biofeedback allows individuals to gain control over their phys- iology by providing real-time reflection of biological activity. Bio- feedback has been demonstrated as an effective treatment for conditions such as hypertension, incontinence, headaches, and others (see Association for Applied Psychophysiology, 2008 for an extensive review). Neurofeedback involves measures of brain activity, such as Electroencephalography (EEG) or real time func- tional magnetic resonance imaging (RTfMRI). Less expensive, safer, and simpler to administer, EEG neurofeedback has been studied more extensively than RTfMRI and is the focus of this review. 1.2. EEG neurofeedback protocols EEG measures scalp wave frequencies classified as delta (1– 4 Hz), theta (4–8 Hz), alpha (8–12 Hz), beta (13–30 Hz), gamma (30–100+ Hz,) and 12–15 Hz representing sensorimotor rhythm (SMR). These protocols utilize the International 10–20 System of placement (Jasper, 1958). Below, different neurofeedback protocols are summarized: 1.3. Beta/SMR Beta waves represent alertness and active concentration (Haenschel, Baldeweg, Croft, Whittington, & Gruzelier, 2000), while SMR is associated with semantic processing and sustained attention (Egner & Gruzelier, 2001). SMR neurofeedback training appears to strengthen thalamic inhibitory function (Sterman, 1996), and has been applied to learning disabilities or attention deficit and hyperactivity disorder (ADHD), as well as to seizure disorders. Some protocols that aim to increase attention combine upregulation of Beta/SMR with downregulation of theta, which is referred to as theta/beta. 0191-8869/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.paid.2012.11.037 ⇑ Tel.: +1 213 821 2859; fax: +1 213 746 9082. E-mail address: sniv@usc.edu Personality and Individual Differences xxx (2013) xxx–xxx Contents lists available at SciVerse ScienceDirect Personality and Individual Differences journal homepage: www.elsevier.com/locate/paid Please cite this article in press as: Niv, S. Clinical efficacy and potential mechanisms of neurofeedback. Personality and Individual Differences (2013), http:// dx.doi.org/10.1016/j.paid.2012.11.037