According to Barr’s The Human Nervous System: An Anatomical Viewpoint, the nervous system is divided into two major sectors: the central nervous system that consists of the brain and spinal cord, and the peripheral nervous system that consists of all the nerves outside the central nervous system.
The central nervous system controls nearly every bodily function outside of a few reflex actions and oversees the actions of the peripheral nervous system. The peripheral nervous system is further divided into several different sectors. The somatic nervous system basically governs voluntary actions and some reflexes, and the autonomic nervous system, which governs involuntary bodily processes, such as heartbeat, digestion, etc. The autonomic nervous system can be further divided into two major subdivisions: the sympathetic nervous system, which basically consists of involuntary processes that “speed up” bodily processes, and the parasympathetic nervous system, which basically consists of involuntary processes that “slow down” bodily processes.
The above explanation is admittedly streamlined and simplified, but basically describes the major divisions of the nervous system in the human body. People typically are not able to consciously control many of the processes in the autonomic nervous system except in indirect manners. For example, you can speed up your heart rate by exercising and slow it down by stopping movement. You can increase your skin temperature by standing outside in the hot sun and decrease it by going into an air-conditioned office. However, a technique that does help some individuals gain control over certain involuntary autonomic nervous system functions is known as biofeedback.
Biofeedback uses certain types of equipment to provide readouts on various body processes (e.g., brain wave activity, heart rate, skin temperature, blood pressure, etc.), and individuals can train themselves to gain some level of control over these autonomic nervous system functions. The technique is believed to have numerous therapeutic benefits.
Major Types of Biofeedback and How They Work
According to The Clinical Handbook of Biofeedback: A Step-By-Step Guide for Training and Practice with Mindfulness, some of the major types of biofeedback used today include:
- Electromyography, which measures muscle tension
- Thermal biofeedback, which measures skin temperature
- Electrodermal activity biofeedback, which monitors perspiration
- Heart rate variability, which monitors heart rate
- EEG biofeedback or neurobiofeedback, which measures specific types of brain wave activity
Typically, biofeedback consists of having electrodes attached to specific spots on the body, depending on what is measured. The electrodes send singles to a monitor that provides feedback, such as auditory feedback, visual feedback, etc., that represents the specific bodily process being measured, such as breathing rate, muscle tension, blood pressure, or brain wave activity. Individuals can learn to alter these autonomic and central nervous system processes by maintaining specific mental states that result in the feedback remaining within a consistent range. For instance, one can maintain a specific type of relaxed state (which is a result of a specific brain wave pattern or decrease in muscle tension) by learning to keep the monitor producing a specific light or sound. When an individual works in conjunction with a therapist, there is initially quite a bit of trial and error involved in order for the individual to learn to maintain the proper desired state, but once the individual learns how to do this, it becomes a simple matter of practicing it in order to decrease issues with muscle tension, headaches, anxiety, etc. In some cases, neurobiofeedback programs use specific types of subliminal messages played with music or white noise in the background to achieve their effects.
Issues That Can Be Treated with Biofeedback
There are numerous claims that certain types of biofeedback techniques can address specific issues. The claims that have received the strongest empirical evidence (research support) are the uses of biofeedback to help individuals learn to relax, decrease muscle tension, and reduce the effects of stress. According to Complementary Therapies in Rehabilitation: Evidence for Efficiency in Therapy, biofeedback techniques to induce different states of relaxation and deal with stress also include training with:
- Progressive muscle relaxation, which consists of a technique of tightening and then relaxing different muscle groups in order to get the feeling of relaxation and reduce tension and stress
- Diaphragmatic breathing techniques, which help to slow down bodily functions and induce relaxation
- The use of guided imagery, such as concentrating on specific situations where one feels relaxed
- Meditation techniques, particularly mindfulness meditation, which helps the individual to focus and let go of negative feelings and other emotions that produce tension
As individuals use these techniques in conjunction with the biofeedback monitor, they can decrease their heart rate, may be able to alter their blood pressure, and ease tense muscles as a result of the feedback they get. Eventually, individuals can learn how to control these functions without the use of the biofeedback monitor. These techniques may be useful in a number of interventions that attempt to control issues with stress-related depression or anxiety, chronic pain (including issues with fibromyalgia and certain types of headaches), issues with high blood pressure, etc.
Learning to manage stress and control muscle tension can assist in the treatment of anxiety disorders, such as panic disorder, phobias, etc. While biofeedback techniques can certainly help with the management of stress, issues with pain, and anxiety, using biofeedback therapy to learn relaxation and stress management appears to have no specific advantages over more traditional approaches using the above techniques (e.g., learning progressive muscle relaxation, diaphragmatic breathing, etc., without biofeedback monitors). In many cases, biofeedback therapy is significantly more expensive than traditional approaches to learning these techniques. However, some individuals may find the use of these biofeedback monitors is more appealing than traditional approaches to learning stress management techniques.
EEG monitors can be used to produce various brainwave patterns (and induce mental states) that increase relaxation. Neurofeedback has been reported to be useful for the treatment of various mental health issues.
Biofeedback Treatments for Mental Health Issues and Substance Abuse
Numerous treatment providers attest to the benefits of neurofeedback, a form of biofeedback that uses a specific type of electroencephalogram (EEG) known as a qualitative EEG (qEGG) in the treatment of several different mental health issues, including attention deficit hyperactivity disorder (ADHD), post-traumatic stress disorder (PTSD), depression, anxiety disorders, and issues with substance abuse. However, the majority of research findings for the utility of this form of treatment for these disorders is weak. For instance, large studies, such as a meta-analytic study reported in the Journal of the American Academy of Child and Adolescent Psychiatry in 2016 failed to find any significant evidence that the technique was useful in the treatment of ADHD symptoms.
The usefulness of biofeedback techniques in treating and managing stress is well documented, and this may contribute to treatment for individuals with PTSD; however, it is important to note that stress management techniques can be learned equally as well without the use of biofeedback apparatus by most people. The stress management benefits of biofeedback techniques can help with issues with depression and anxiety, but the same caveat regarding individuals becoming equally adept at using stress management techniques with or without biofeedback apparatus remains.
There remain very few reliable research studies that use randomized controlled trials or meta-analytic studies regarding the effectiveness of biofeedback in the treatment of substance use disorders compared to traditional substance use disorder therapy and substance use disorder interventions. Some research has suggested that neurobiofeedback might have some utility in identifying who might respond to a particular type of treatment, but this research is preliminary.
Numerous sources have warned against relying on neurofeedback as the sole method of intervention for these disorders. At best, the technique may help individuals to learn stress management techniques, reduce tension, reduce certain types of anxiety, and provide a complementary and adjunctive form of treatment to already well established empirically validated treatment protocols for these disorders. At the time of this writing, there is no reason to consider the use of neurofeedback or any other form of biofeedback as a standalone treatment for substance use disorders or behavioral addictions.