Static and Kinetic Disequilibrium are Central Neural Signs in Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome-Therapeutic Effect of Repetitive Transcranial Magnetic Stimulation.

Background: Chronic fatigue syndrome is primarily caused by myalgic encephalomyelitis (ME)-associated dysfunction of the central nervous system. Postural instability or disequilibrium is a typical neural sign and is classified as static or kinetic.

Methods: A total of 160 ME patients (53 males and 107 females) with a mean age of 37 ± 12 years were enrolled in this study. They underwent both the Romberg test for static disequilibrium and the tandem gait test with turn and return for kinetic disequilibrium.

Results: Static disequilibrium was found in 40 (25%) patients who showed instability when standing with both feet together and eyes either open (n = 7, 4%) or closed (n = 33, 21%). Kinetic disequilibrium was found in 71 (44%) patients, with 57 (36%) being positive for the straight tandem gait test. Fourteen (9%) patients were negative for the straight tandem gait test, but showed a positive result after turning and returning. Almost all patients with static disequilibrium also had kinetic disequilibrium (39/40, 98%). Patients with static and/or kinetic disequilibrium had a significantly higher prevalence of orthostatic intolerance, diagnosed as failure to complete the 10-min standing test, compared with patients without disequilibrium. They also had a significantly higher median performance status score (0-9) for restricted activities of daily living. Both types of disequilibria were recovered in 11 (85%) of 13 patients treated with repetitive transcranial magnetic stimulation (rTMS) of the left dorsolateral prefrontal cortex and primary motor area in the brain, suggesting a central vestibular origin.

Conclusions: Static disequilibrium related to orthostatic intolerance, and kinetic disequilibrium related to gait disturbance are both prevalent in patients with ME and are important central neural signs that restrict activities of daily living. rTMS treatment effectively alleviated these disequilibria.

Clinical trial registration: The study has been registered on https://jrct.mhlw.go.jp/ (registration number: jRCT1042240065; registration date: July 30, 2024).