Biofeedback? Neurofeedback?
by Kayle Sandberg-Lewis, LMT, MA, BCIA-Senior Fellow
What is the difference between biofeedback and neurofeedback?
The short answer: Biofeedback is a general term regarding feedback from anywhere in the body while neurofeedback refers to feedback specifically involving the brain.
That, of course, does not answer the question, “What is ‘feedback’?”
When you visit your health care provider, someone probably takes your “vitals”– signals coming from your body - and types it in your medical record. You may or may not be told what those signals are or what they mean.
The living human body is constantly creating signals, but we are, for the most part, unaware of their presence or significance. Your pulse reflects your heart rate. Your core temperature is the result of the heat generated by the working body – it may indicate a problem with your metabolism or the presence of something your immune system is addressing. The point is, the biological systems in our bodies are talking, but most of us don’t know how to listen. We need help understanding what our bodies are able to communicate through the signals they create.
Physiologists learned to ascertain and access biological signals.
Psychophysiologists identified the links between specific biological signals and the autonomic nervous system (ANS), the part of the brain that modulates an individual’s arousal level – whether we’re calm or anxious. In short, our stress response.
Applied psychophysiologists have created ways to monitor those signals and feed them back to the person who is creating them so they can modify their own responses to stressors.
This process is biofeedback, a way for a person to learn to self-regulate and defuse the stress response.
According to Patricia A. Norris, a psychoneuroimmunologist,
…the acquisition of volitional self-regulation modifies how stress is perceived and modifies the physiologic responses to stress. Learning to control physiologic responses to stress generally leads to a sense of energy and exhilaration, as opposed to worry, despair, and this has a powerful healing effect.
Because the various systems of the body are creating many different signals, there are several forms of biofeedback. Some are likely to be used together while others are more apt to be used in isolation. Some examples follow.
· Heart rate variability (HRV): The pumping heart creates a signal that can be monitored and trained, to a certain extent, as it pulses throughout the body. HRV is focused on the difference between the high points and the low points from one beat to the next – a direct indication of the balance between sympathetic (uptick) and parasympathetic (downbeat) function within the ANS. Training can help modulate arousal levels and lead to better focus in cases of attention issues such as ADD/ADHD. Most people find HRV training calming and easily transferable to day-to-day situations.
· Electromyography (EMG): When muscles tense and relax it is because the nerves in the muscles are changing the messages they emit, creating signals that can be monitored and trained. The equipment used is modified depending on which muscles are being trained. EMG feedback is used in addressing tension headaches, neck and shoulder pain, cerebral palsy issues, and muscle reeducation after surgery or injury. Specifically trained physical therapists use EMG to address pelvic floor issues. EMG is often used in conjunction with other forms of feedback.
· Electrodermography (EDG): Eccrine sweat glands are distributed over most of the body’s surface but are particularly numerous – an average of three thousand per square inch - on the palms of the hands and the soles of the feet. These sweat glands are innervated by nerve fibers from the sympathetic branch of the ANS and are intimately linked to the gastrointestinal system. (The same nerve fibers control the arrector pili muscles in the skin – the tiny muscles that give us goose bumps.) Because sweat is high in electrolytes - salty - it conducts electricity easily. In EDG feedback, sensors are placed on two fingers and a tiny, imperceptible current is run between the sensors. The sensors are attached to equipment that transforms the electrical signal into sound and can be used to help train a person to be less anxious. Many people report feeling calmer in stressful situations and have less stress-related gastric pain. EDG has also been used successfully in addressing essential hypertension.
· Peripheral temperature training: The peripheral blood supply to the fingers and toes is provided by delicate vessels with a strong link to the ANS, meaning many people when under stress have cold hands and feet. The ANS will reduce blood supply to the extremities when danger is perceived. Some people generalize this stress response and have chilly extremities most of the time. Training peripheral temperature can increase blood flow, which is warming, and help address essential hypertension, Raynaud’s disease, migraines, and peripheral neuropathy, as well as promote a general sense of wellbeing.
· Pneumography (PNG): Sensors around the chest and diaphragm record velocity and force of the movement of the chest during respiration and can extrapolate the tidal volume of the lungs – how deeply and consistently one breathes. As feedback, it is used to address maladaptive breath patterns in COPD, asthma, and cystic fibrosis. PNG encourages the use of the diaphragm as the primary muscle in breathing, discouraging chronic hyperventilation – breathing shallowly and too rapidly. The sensors can serve double duty and report on the relationship between the breath and the heart, giving a readout of something called respiratory sinus arrhythmia (RSA). While “arrhythmia” sounds bad, in this case it describes the natural, healthy changes in heart rate that occur between inhalation and exhalation.
· Electroencephalogram (EEG): The neurons of the brain are firing whether we’re awake or asleep, but because the brain is tucked in the skull and protected by three layers of tough fibrous tissue called the meninges, the signals created by those neurons are hard to detect. The conversation within the brain is private. It took Hans Berger over 20 years of diligent effort to finally pick up the rudiments of what became known as the EEG. Now, through refinement of equipment and development of an electrolyte rich paste, sensors can be attached to the scalp and relay neuronal activity from the brain. Because the brain is involved in every function of the body, EEG biofeedback or neurofeedback has been used in addressing many issues. Sleep, chronic pain, seizures, attention issues, and processing of emotional trauma are some of the issues that have been researched with positive results. Feedback may be vibrational, audio, and/or visual – such as movies or specially designed video games. In the case of the Low Energy Neurofeedback System (LENS) the feedback is an electromagnetic pulse reflecting the dominant frequency of the area being monitored, imperceptible feedback that converses directly with the body.
· passive infrared Hemoencephalography (pirHEG): pirHEG is unique in the field of neurofeedback by reflecting the level of participation of the prefrontal cortex (pfc). The pfc oversees coordinating the efforts of the rest of the brain, much as a conductor directs the smooth performance of an orchestra. When conductors do their jobs well, orchestras perform at their best. When conductors lose their place in the score or drop their batons and take a break, the orchestra is left to flounder – each musician left adrift. The same goes for the brain. That means when the pfc is functioning well, focus is good, emotions are manageable, and life seems to flow smoothly. When the pfc goes offline, distraction and/or emotional overwhelm can reign supreme. During pirHEG, an infrared sensor is strapped on the forehead where it monitors the activity in the pfc which is situated right behind the forehead. DVD movies provide the feedback.
· Interactive Metronome (IM): Brain function relies on timing. When our timing is “off”, so is our capacity to process information, both audio and visual. Our focus, ability to make plans, and coordinate our movements suffer. Our balance, memory, attention, sleep – even our sense of humor – are reliant on the capacity of the brain to get things in proper sequence in a timely manner. (This may be most obvious when learning to play a musical instrument.) During IM, a person listens to a metronome and claps their hands or taps their toes on the beat. Visual feedback is given in milliseconds, helping the brain learn to tighten its response to stimuli. Students, athletes, musicians, elders, and those with cognitive impairments have benefited from IM.
So, when your medical professionals record your vitals, they get clues about the state and functioning of your body. The benefits you derive from that information is indirect because they’re using it to help formulate your health care plan. When, instead, the same or similar information is given back to you in real time through sensors on your body, you have the opportunity to directly interact with your body’s signals and learn how to regulate them. This is not superior to medical care; it is adjunctive. It is an educational process that is empowering and can lead to self-control at the most fundamental level.
References
Andreassi, John L. Psychophysiology. Psychology Press, 23 July 2013.
Asahina, Masato, et al. “Sweating on the Palm and Sole: Physiological and Clinical Relevance.” Clinical Autonomic Research, vol. 25, no. 3, 17 Apr. 2015, pp. 153–159, https://doi.org/10.1007/s10286-015-0282-1.
Basmajian, John V. Biofeedback. Lippincott Williams & Wilkins, 1989.
How It Works - Interactive Metronome. 13 June 2013, www.interactivemetronome.com/how-it-works-2.
Larsen, Stephen. The Neurofeedback Solution. Rochester, Inner Traditions International, Limited, 2012.
Schwartz, Mark S, and Frank Andrasik. Biofeedback: A Practitioner’s Guide. New York, London, The Guilford Press, 2017.
Yasuma, Fumihiko, and Jun-Ichiro Hayano. “Respiratory Sinus Arrhythmia: Why Does the Heartbeat Synchronize with Respiratory Rhythm?” Chest, vol. 125, no. 2, 2004, pp. 683–90, www.ncbi.nlm.nih.gov/pubmed/14769752, https://doi.org/10.1378/chest.125.2.683.
Kayle Sandberg-Lewis holds a M.A. in Behavioral Medicine, the study of how what we do in our daily lives affects our well-being. She has over three decades experience in stress management and is board certified in neurofeedback, which she introduced to her practice in 1996. She is certified in neurofeedback by the Biofeedback Certification International Alliance (BCIA).
Hive Mind Medicine blog posts are for educational purposes only and are not intended as medical advice. Please consult with your health care practitioner for personalized guidance.