- A pilot study (n = 10) of motor cortex TMS as a treatment for functional (psychogenic) weakness is described.
- Although there was a small improvement in self-reported symptom severity immediately after treatment this was not clinically significant or sustained.
- Half of the participants reported late-onset adverse effects.
- A single session of non-neuromodulatory TMS without additional therapy input was not an effective treatment for this cohort of stable chronic outpatients.
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.
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 2.3 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.
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.
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.