Transcranial magnetic stimulation as a treatment for functional (psychogenic) upper limb weakness

Objective: There has been a recent resurgence of interest in physical treatments for functional motor disorders (FMD) including Transcranial Magnetic Stimulation (TMS). This pilot study aimed to test the effectiveness of a single session of motor cortex TMS as a treatment for functional upper limb weakness. Methods: Ten subjects with a diagnosis of functional upper limb weakness were randomised to immediate (n = 7) or delayed (3 months) (n = 3) TMS treatment. Median age was 35 (range 23-52) and median symptom duration was 23 years (range 5 months - 20 years). 46-70 single pulses were applied to the motor cortex at 120-150% motor threshold. We used a verbal protocol designed to standardized the effects of suggestion. Primary outcome measures were self-reported symptom severity, grip strength and tapping frequency immediately after treatment, and symptom severity and disability (SF-12 and Modified Rankin Scale (MRS)) after 3 months. Results: There was a small significant reduction in symptom severity immediately after treatment, but no improvement in grip strength or tapping frequency and no change in symptom severity, SF-12 or MRS 3 months after treatment. Small numbers precluded comparison of immediate treatment with delayed treatment. Four of eight subjects responding to three-month follow-up reported late-onset adverse effects. Conclusion: This pilot study suggests limited benefits for TMS as a one-off non-neuromodulatory treatment for stable chronic outpatients. TMS may still have a role alongside more intensive multidisciplinary therapy input, or in patients with severe deficits where the possibility of normal movement can be hard to demonstrate. (C) 2016 Elsevier Inc. All rights reserved.