Quantitative EEG findings in fibromyalgia syndrome, TENS and acupuncture efficacy in the treatment

ABSTRACT Fibromyalgia syndrome (FMS) is a syndrome characterized by pain on tendino-musculosceletal regions, also referred to as "tender spots". Non-musculoskeletal symptoms like fatigue, sleep disorder, and irritable colon syndrome may also be present. Women are affected 9-10 times more than men. Theories regarding the physiopathology of fibromyalgia used to focus on mainly muscle tissue derived processes; however, recent studies reveal some concerns about central integration of pain. The results of neurophysiological studies demonstrate that, instead of peripheral pain sensitization, patients suffer from central nervous system hypersensitivity. This kind of hypersensitivity may derive from a decrease in central inhibitory functions. In this work, we aim to investigate the changes in quantitative electroencephalography (qEEG) in FMS patients. We also aimed to determine the role of TENS and acupuncture interventions on pain control, and their effect on qEEG. 42 fibromyalgia patients, and 21 healthy volunteers were included in the study. The severity and character of the pain in patients was evaluated using Short McGill Pain Questionnaire, and pain thresholds of tender spots were measured by algometer. Depression level of patients was established with Beck depression scale. Fibromyalgia Impact Questionnaire was used to evaluate the disease severity and quality of life. The pain and tiredness status of patients in TENS and acupuncture group was measured using visual analog scale (VAS), prior to EEG. After TENS and acupuncture interventions, a new VAS evaluation was run to determine the change in pain levels. Patients were randomly grouped into either TENS, or acupuncture groups (n=21 in each group). Briefly, a 10 minutes EEG record was taken from each patient, followed by a 20 minutes session of either TENS, or acupuncture. Following the intervention, another EEG record of 10 minutes was granted FMS patients in TENS and acupuncture groups had similar qEEG findings. When qEEG findings of FMS patients were compared to control subjects', there was a decrease in the power of low and mid frequency waves. For FMS patients, better pain scores were achieved after TENS or acupuncture. In TENS group, an increase in alpha power on the left anterior and the right posterior regions, as well as in theta power on the right posterior region were observed following the treatment. No differences in delta, or beta power were revealed. In acupuncture group, an increase in alpha power on the right and left posterior regions, an increase in theta power on the right posterior region, and an increase in beta power on the right and left posterior regions were observed. Theoretically, alpha waves reflect the activity of inhibitory neurons. The observed increase in alpha power may be the consequence of inhibitory neuron activation of TENS, or acupuncture. In conclusion, in FMS patients resting EEGs, there is a decrease in low and mid frequency waves. TENS, and acupuncture treatment interventions led to a decrease in pain and an increase in inhibitory activity on qEEG. Keywords: Fibromyalgia, quantitative EEG, TENS, acupuncture