Date Published: September 25, 2018
Publisher: Public Library of Science
Author(s): Anne Sofie Bøgh Malling, Bo Mohr Morberg, Lene Wermuth, Ole Gredal, Per Bech, Bente Rona Jensen, Alfonso Fasano.
Parkinson’s disease is caused by dopaminergic neurodegeneration resulting in motor impairments as slow movement speed and impaired balance and coordination. Pulsed electromagnetic fields are suggested to have neuroprotective effects, and could alleviate symptoms.
To study 1) effects of 8-week daily transcranial pulsed electromagnetic field treatment on functional rate of force development and movement speed during two motor tasks with different levels of complexity, 2) if treatment effects depend on motor performance at baseline.
Ninety-seven persons with Parkinson’s disease were randomized to active transcranial pulsed electromagnetic field (squared bipolar 3 ms pulses, 50 Hz) or placebo treatment with homebased treatment 30 min/day for 8 weeks. Functional rate of force development and completion time of a sit-to-stand and a dynamic postural balance task were assessed pre and post intervention. Participants were sub-grouped in high- and low-performers according to their baseline motor performance level. Repeated measure ANOVAs were used.
Active treatment tended to improve rate of force development during chair rise more than placebo (P = 0.064). High-performers receiving active treatment improved rate of force development during chair rise more than high-performers receiving placebo treatment (P = 0.049, active/placebo: 11.9±1.1 to 12.5±1.9 BW/s ≈ 5% / 12.4±1.3 to 12.2±1.3 BW/s, no change). No other between-treatment-group or between-treatment-subgroup differences were found. Data on rate of force development of the dynamic balance task and completion times of both motor tasks improved but did not allow for between-treatment differentiation.
Treatment with transcranial pulsed electromagnetic fields was superior to placebo regarding functional rate of force development during chair rise among high-performers. Active treatment tended to increase functional rate of force development while placebo did not. Our results suggest that mildly affected persons with Parkinson’s disease have a larger potential for neural rehabilitation than more severely affected persons and indicate that early treatment initiation may be beneficial.
Parkinson’s disease (PD) is a neurodegenerative disease primarily affecting the dopaminergic neurons in the basal ganglia resulting in functional motor impairments such as slow movement speed (bradykinesia), rigidity, tremor and impaired balance and coordination of movements. The disease influences the ability to activate the muscles fast and without co-activation of inappropriate muscles [1, 2]. This is reflected in a lower voluntary rate of force development (RFD) in both isometric and functional setups compared to age-matched healthy peers [2–5] in spite of an intact capacity of force generation at the muscular level . RFD is important in performing daily activities where the time available for force generation is short, e.g. managing balance challenging tasks, response to sudden mechanical perturbations, and safe locomotion.
The main finding of this study indicates a probable positive effect of treatment with T-PEMF on RFD during chair rise, and that this positive effect was present among the participants with high performance levels at baseline. In addition, we found improved motor performance in PDP from baseline to endpoint independently of the treatment received.
In this study, which is the first on the effect of long-term T-PEMF treatment on functional rate of force development and movement speed in PD, we found that T-PEMF treatment was superior to placebo treatment to increase functional RFD during chair rise in the PDPHigh group. Specifically, the functional RFD tended to increase in the PDPHigh group receiving T-PEMF treatment, whereas no effect was found in the PDPHigh group receiving placebo treatment. Thus, our results support the idea that mildly affected persons with PD have a larger potential for neural rehabilitation than more severely affected PDP. Our data on functional RFD during the more complex DPB task and completion times of both the STS and DPB task improved but did not allow for differentiation between T-PEMF and placebo treatments. In perspective, long-term treatment with T-PEMF could have a potential as an add-on treatment for PD, and the results of the present study suggest that an early treatment initiation may be beneficial. However, studies with even longer treatment periods and in vivo mechanisms of action are recommended.