Neurobiofeedback and its Influence on the Autonomic Nervous System and On Symptoms in Fibromyalgia Patients

Abstract

Fibromyalgia is a common and difficult to treat widespread pain disorder. It is a condition of heightened generalized sensitization to sensory input presenting as a complex of symptoms including pain, sleep dysfunction and fatigue. The pathophysiology could include dysfunction of the central nervous system, pain modulatory system and dysautonomia Although FM essential features are widespread pain and allodynia, there are many other distinctive features, including fatigue, morning stiffness, non-refreshing sleep, paresthesias, anxiety, headache, orthostatic hypotension, dizziness, dry eyes, dry mouth and GI irritability. Many of these symptoms can be explained by autonomic nerve dysfunction.

Different groups of investigators have described abnormal autonomic nerve dysfunction of FM in different ways. Some have used tilt table testing showing POTS (postural orthostatic tachycardia syndrome) in a significant population. Others have used the Composite Autonomic Symptom Scale (COMPASS). This is a multidimensional questionnaire containing 9 different domains of autonomic function. A recent method is based on the well known fact that heart rate is not fixed, but varies from beat to beat. The antagonistic effects of the sympathetic and parasympathetic branches of the autonomic nervous system on the sinus node dictate this constant periodic variability. Heart rate variability can be studied in time or frequency domains or both. The higher time domain variability indexes signify more parasympathetic influx on the sinus node. The ratio of low frequency/high frequency band is regarded as reflecting sympathetic activity.

The Intellewave heart rate variability system is a device that uses a frequency domain approach to characterize fluctuation of RR intervals in an EKG that can automatically analyze this data for power spectral analysis using sophisticated algorithms. The device can give information on the sympathetic and parasympathetic nervous system. The patient is subjected to two test modalities; the first is the lying to standing test (orthostatic test) and second is the Valsalva maneuver combined with deep breathing. A Cardio-belt applied on the patient’s chest collects this EKG information and transmits them to the computer through a bluetooth adapter. We have found the majority of our patients with fibromyalgia have autonomic dysfimction, either increased sympathetic tone and/or decreased parasympathetic tone. Some researchers have shown that this dysautonomia can be characterized as a sympathetic nervous system that is persistently hyperactive, but hypo reactive to stress. This apparent paradox agrees with a basic physiologic principle demonstrating that chronic stimulation of the beta adrenergic receptors leads to desensitization and down regulation. Relentless sympathetic hyperactivity may explain sleep disorders, anxiety, pseudo Raynaud’s phenomenon, sicca symptoms and intestinal irritability. These patients are unable to respond to different stressors, thus explaining the fatigue etc In some patients the parasympathetic system is also depressed Recent research has proven acetylcholine receptors on dendrites and macrophages of the immune system These receptors produce intracellular signals that inhibit cytokine synthesis and release., and are downregulated when parasympathetic influence is markedly decreased. This can also explain some of the fatigue and mild mucosal inflammation that is sometimes found in FM.

Researchers are trying various techniques to change autonomic tone and hopefully improve symptoms in FM. using such modalities as cognitive behavioral therapy, acupuncture and pharmacological therapy, exercise etc. Some approved drugs have yet to be tested on the autonomic nervous system, to prove a possible other mechanism of action. In our office, we have shown cranial electric stimulation with the alpha stim to help correct autonomic dysfunction via intelliwave testing. Recently my colleagues at Rutgers University and RWJ Medical School have described the technique of heart rate variability (HRV) biofeedback in fibromyalgia. They speculated that decreased responsiveness of the baroreflex to blood pressure might be involved in the abnormal sympathovagal response to postural change. HRV biofeedback is designed specifically to target autonomic reactivity. The majority of their FM patients derived significant improvement in functioning, depression and pain. This was a pilot study and needs to be repeated blinded, with larger numbers and verified with the intelliwave system as to the precise role of HRV in improving autonomic nerve dysfunction.

We have recently been using a technique called, EEG neuro-frequency monitoring and neuro-biofeedback in our FM patients. This technique has recently been used successfully in many psychiatric and neurologic conditions. It has recently been noted that the ANS includes not only the afferent interoceptive arm and the efferent visceral motor arms, but also includes higher level integrative and regulatory neural networks found at various levels in the brain. Our hypothesis is that if we are able to change the abnormal brain frequency in specific areas of the brain we may alter the autonomic dysfunction and improve symptoms. We also would like to prove that once the autonomic dysfunction is improved, the patients’ pain, sleep disorder, stress level, and cognitive dysfunction will also improve. Besides autonomic nerve testing, we plan on testing trigger points and using the fibromyalgia impact questionnaire (FIQ) to show this improvement. The FIQ is the instrument most often used to measure FM severity. Functional neuroimaging studies have recently been used to prove central pain abnormalities in FM. Specifically, FM patients have increased activity in the regions of the brain that code for the sensory intensity of stimuli (e.g. the primary and secondary somatosensory cortices, posterior insula and the thalamus) In the future we would like to use neuroimaging to also show the affects of neurobiofeedback and to more closely follow the brain -autonomic system connection.

As discussed above, the autonomic nervous system may be the conduit to which the brain can control not only pain perception but even the immune system. The vagus nerve influences so much of the body that it probably is the most important conduit in the mind body connection. Abundant evidence therefore points to the concept that complex behavior originating in higher brain centers can directly influence outflow through the vegus nerve and the autonomic nervous system. This concept has been used to explain the increased mortality in depression, especially depression associated with myocardial infarction, the increased morbidity and mortality in the autoimmune diseases when patients are under stress and depressed and now another etiology to explain the myriad symptoms of fibromyalgia. Neurobiofeedback may give us another possible treatment of this common disorder.