A Study of the Effect of Rhythmic Sensory Stimulation on Fibromyalgia

Fibromyalgia is a chronic pain disorder associated with widespread pain that dramatically impacts patients' quality of life. Its exact cause has not yet been identified, however, recent studies indicate that fibromyalgia is associated with a significant imbalance of the connectivity within brain networks associated with pain, decreased functional connectivity in the descending pain-modulating system, and increased activity in the pain matrix related to central sensitization. It has been suggested that treatments that stimulate or induce coherent neuronal activity, and synchronize dysregulated brain circuitry, have significant benefits in improving pain management and enhancing patients' quality of life.

An example of a non-invasive treatment that is thought to indirectly stimulate neuronal coherence is Rhythmic Sensory Stimulation (RSS) in gamma frequencies. RSS stimulates the mechanoreceptors in the body using gamma-frequency sounds (e.g., 40 Hz) by means of speakers in a chair. Previous research demonstrates significantly improved pain management in several pain conditions (e.g., rheumatoid arthritis, low-back pain, sports injuries); however, little is known about the effect of RSS with gamma-frequency sound stimulation on fibromyalgia. The use of RSS to treat fibromyalgia was first explored very recently and findings indicate that this treatment could be effective for individuals with fibromyalgia given that gamma-frequency sound stimulation indirectly stimulates neuronal coherence.

Aim: The present study aims to examine the effects of gamma frequency rhythmic sensory stimulation on fibromyalgia symptoms. Treatment effectiveness will be assessed by examining whether sensory stimulation will produce clinically meaningful changes in fibromyalgia symptom severity and whether treatment response will differ between the two treatment parameters.

Intervention: Fifty patients with a formal diagnosis of fibromyalgia were randomly assigned to two test groups. One group received vibrotactile stimulation from a continuous sine wave single-frequency stimulation (40 Hz) for 30 minutes, five days per week, over five weeks, concomitant with usual care. The second group completed the same treatment protocol but received different stimulation consisting of random and intermittent complex wave gamma-range vibrotactile stimulation. Measures of pain severity, fibromyalgia symptoms, sleep quality, and depression will be compared before and after treatment between the two groups.

The results of the present study will help to better understand the effectiveness of RSS for treatment of chronic pain disorders, such as fibromyalgia, and contribute to the development of future studies to investigate the mechanisms underlying clinical responses to rhythmic sensory stimulation.

Inclusion criteria

• Clinical diagnosis of fibromyalgia conducted by the medical staff at Wasser Pain Management Centre;
• Ability to read and write English adequately;
• Have satisfactory hearing bilaterally (self-reported);
• Have the ability to operate the supplied device.

Exclusion criteria

• Acute and active inflammatory conditions (e.g., rheumatoid arthritis, osteoarthritis, autoimmune disease);
• Unstable medical or psychiatric illness;
• History of psychosis, epilepsy, seizures;
• Pregnancy or breast feeding;
• Hemorrhaging or active bleeding;
• Thrombosis, angina pectoris;
• Heart diseases, such as hypotension, arrhythmia, pacemaker;
• Substance abuse in the last year;
• Recently prolapsed vertebral disc;
• Recovering from a recent accident with back or neck injury.