Effects of long-term treatment with transcranial pulsed electromagnetic fields in Parkinson's disease on kinematic and electrophysiological tremor.

Abstract

Previous studies of the use of transcranial pulsed electromagnetic fields (T-PEMF) as a treatment for Parkinson's disease (PD) for a short period have shown positive results. The aim was to investigate the effect of long-term treatment with T-PEMF on tremor quantified by forearm muscle activation and hand acceleration in PD. Patients (n = 14) received three 8-week periods of daily T-PEMF treatment (±50 V, 3 ms, 55 Hz, 30 min/day). Furthermore, a control group with PD (n = 8, no treatment) and a healthy reference group (n = 5) participated. The participants performed a postural task (3x1min) sitting with arms extended, horizontal, and parallel. Electrophysiological (surface electromyography (EMG) theta-band power in the tremor frequency area, 4-8 Hz) and kinematic tremor (accelerometer tremor intensity, 3-9 Hz) analyses were performed at baseline, week 17 and week 27. At baseline, the PD patients (n = 22, all patients) had consistently significantly higher levels of EMG theta-band power and tremor intensity in the most affected side compared to the healthy reference group. The T-PEMF treatment decreased the median EMG theta-band power (most affected side) consistently, with a statistically significant decrease in flexor muscles and a tendency in extensor muscles. Furthermore, the T-PEMF-treatment decreased median tremor intensity statistically (both sides). In contrast, the PD control group did not change statistically (most affected side) from baseline to week 27. Long-term treatment with T-PEMF changed forearm EMG power and hand acceleration in the tremor frequency spectrum towards healthy values. Thus, the present results add further knowledge to the effects of T-PEMF treatment in PD.