Efficacy of Repetitive Trans-spinal Magnetic Stimulation for Patients with Parkinson's Disease: a Randomised Controlled Trial

Trans-Spinal Theta Burst Magnetic Stimulation in Parkinson's Disease and Gait Disorders

BACKGROUND

Gait disorders in patients with Parkinson's disease (PD) can become disabling with disease progression without effective treatment.

OBJECTIVES

To investigate the efficacy of intermittent θ burst trans-spinal magnetic stimulation (TsMS) in PD patients with gait and balance disorders.

METHODS

This was a randomized, parallel, double-blind, controlled trial. Active or sham TsMS was applied at third thoracic vertebra with 100% of the trans-spinal motor threshold, during 5 consecutive days. Participants were evaluated at baseline, immediately after last session, 1 and 4 weeks after last session. Primary outcome was Total Timed Up and Go (TUG) values comparing active versus sham phases 1 week after intervention. The secondary outcome measurements consisted of motor, gait and balance scales, and questionnaires for quality of life and cognition.

RESULTS

Thirty-three patients were included, average age 68.5 (6.4) years in active group and 70.3 (6.3) years in sham group. In active group, Total TUG mean baseline was 107.18 (95% CI, 52.1-116.1), and 1 week after stimulation was 93.0 (95% CI, 50.7-135.3); sham group, Total TUG mean baseline was 101.2 (95% CI, 47.1-155.3) and 1 week after stimulation 75.2 (95% CI 34.0-116.4), P = 0.54. Similarly, intervention had no significant effects on secondary outcome measurements. During stimulation period, five patients presented with mild side effects (three in active group and two in sham group).

DISCUSSION

TsMS did not significantly improve gait or balance analysis in patients with PD and gait disorders. The protocol was safe and well tolerated. © 2024 International Parkinson and Movement Disorder Society.

Different Effect Sizes of Motor Skill Training Combined with Repetitive Transcranial versus Trans-Spinal Magnetic Stimulation in Healthy Subjects

Repetitive transcranial magnetic stimulation (rTMS) is used to enhance motor training (MT) performance. The use of rTMS is limited under certain conditions, such as after a stroke with severe damage to the corticospinal tract. This raises the question as to whether repetitive trans-spinal magnetic stimulation (rSMS) can also be used to improve MT. A direct comparison of the effect size between rTMS and rSMS on the same MT is still lacking. Before conducting the study in patients, we determined the effect sizes of different stimulation approaches combined with the same motor training in healthy subjects. Two experiments (E1 and E2) with 96 subjects investigated the effect size of combining magnetic stimulation with the same MT. In E1, high-frequency rTMS, rSMS, and spinal sham stimulation (sham-spinal) were applied once in combination with MT, while one group only received the same MT (without stimulation). In E2, rTMS, rSMS, and sham-spinal were applied in combination with MT over several days. In all subjects, motor tests and motor-evoked potentials were evaluated before and after the intervention period. rTMS had the greatest effect on MT, followed by rSMS and then sham-spinal. Daily stimulation resulted in additional training gains. This study suggests that rSMS increases excitability and also enhances MT performance. This current study provides a basis for further research to discover whether patients who cannot be treated effectively with rTMS would benefit from rSMS.

Controversies and Clinical Applications of Non-Invasive Transspinal Magnetic Stimulation: A Critical Review and Exploratory Trial in Hereditary Spastic Paraplegia

Magnetic stimulation is a safe, non-invasive diagnostic tool and promising treatment strategy for neurological and psychiatric disorders. Although most studies address transcranial magnetic stimulation, transspinal magnetic stimulation (TsMS) has received recent attention since trials involving invasive spinal cord stimulation showed encouraging results for pain, spasticity, and Parkinson’s disease. While the effects of TsMS on spinal roots is well understood, its mechanism of action on the spinal cord is still controversial. Despite unclear mechanisms of action, clinical benefits of TsMS have been reported, including improvements in scales of spasticity, hyperreflexia, and bladder and bowel symptoms, and even supraspinal gait disorders such as freezing and camptocormia. In the present study, a critical review on the application of TsMS in neurology was conducted, along with an exploratory trial involving TsMS in three patients with hereditary spastic paraplegia. The goal was to understand the mechanism of action of TsMS through H-reflex measurement at the unstimulated lumbosacral level. Although limited by studies with a small sample size and a low to moderate effect size, TsMS is safe and tolerable and presents consistent clinical and neurophysiological benefits that support its use in clinical practice.