The effect of 8 weeks of treatment with transcranial pulsed electromagnetic fields on hand tremor and inter-hand coherence in persons with Parkinson's disease

Electromagnetic radiation therapy for Parkinson's disease tremor reduction- systematic reviews and Bayesian meta-analyses for comparing the effectiveness of electric, magnetic and light stimulation methods

PURPOSE

Tremor is one of the key characteristics of Parkinson's disease (PD), leading to physical disabilities and often showing limited responses to pharmacological treatments. To suppress tremors in PD patients, several types of non-invasive and non-pharmacological methods have been proposed so far. In the current systematic review, three electromagnetic-based radiation strategies including electrical stimulation, magnetic stimulation, and light stimulation methods were reviewed and compared.

METHODS

Major databases were searched to retrieve eligible studies. For the meta-analysis, a random-effect Bayesian framework was used. Also, heterogeneity between studies was assessed using I2 statistic, prediction interval, and tau2. Publication bias was assessed using funnel plot, and the effectiveness of methods for reducing tremor was compared using network Bayesian meta-analysis.

RESULTS AND CONCLUSION

Thirty-one studies were found for qualitative analysis, and 16 studies were found for quantitative synthesis. Based on the suppression ratio, methods can be ordered as electrical stimulation, light therapy, and magnetic stimulation. Furthermore, the results showed that electrical and magnetic stimulation were more effective for tremor suppression at early stages of PD, while light therapy was found to be more effective during the later stages of PD.

Non-Invasive Transcutaneous Afferent Patterned Stimulation Therapy Offers Action Tremor Relief in Parkinson's Disease

Background

Many patients with Parkinson's disease (PD) experience action tremor (including postural and kinetic tremors) that impair activities of daily living. Transcutaneous afferent patterned stimulation (TAPS) is a non-invasive neuromodulation therapy that modulates tremorgenic activity at the ventral intermediate nucleus (VIM). Most TAPS evidence evaluated relief of action tremor associated with essential tremor (ET). This study evaluated whether TAPS results in similar relief of action tremor associated with PD.

Methods

Forty PD patients with action tremors were enrolled in a prospective, single-arm, open-label study with four weeks of unsupervised at-home TAPS sessions in the dominant hand twice daily in between supervised TAPS sessions at two telemedicine appointments. The primary endpoint was change in tremor power as measured by the on-board accelerometer before and immediately after a stimulation session. Additional study endpoints included change in Movement Disorder Society-Sponsored Unified Parkinson's Disease Rating Scale Part III (MDS-UPDRS), change in Bain and Findley Activities of Daily Living (BF-ADL) scale, and clinician and patient global impressions of improvement (CGI-I and PGI-I).

Results

TAPS reduced tremor power by 64% (54%-79%) (median (interquartile range), p < 0.001), with 79% of patients experiencing at least 50% reduction. When comparing pre-stimulation scores at visit 1 to post-stimulation scores at visit 2, TAPS improved per-task MDS-UPDRS III ratings of postural and kinetic tremors (0.6 ± 0.5, t(34) = 7.05, p < 0.001) and per-task patient-ratings of BF-ADL ADL upper limb motion ratings (0.5 ± 0.5, t(34) = 5.69, p < 0.001). Clinicians reported improvement in 78-83% of patients and 75-80% of patients reported improvement. Adverse events, most commonly skin reaction at the stimulation site, occurred in 18% of patients.

Conclusion

Objective, clinician-rated, and patient-rated assessments demonstrated that TAPS provided clinically meaningful relief of action tremor in patients with PD.

Physical therapy interventions for the management of hand tremors in patients with Parkinson's disease: a systematic review

BACKGROUND

Several physical therapy modalities have been used to improve hand tremors in patients with Parkinson's disease (PD). However, little is known about the efficacy of these techniques. Therefore, we conducted this study to synthesize evidence from published studies on the efficacy of physical therapy techniques for hand tremors in PD patients.

METHODS

We followed the PRISMA statement and Cochrane handbook guidelines when conducting this study. We conducted an electronic literature search of PubMed, Cochrane Central Register of Clinical Trials, Web of Science, Ovid, and Embase, and then we selected clinical trials assessing the efficacy of any physical therapy intervention for hand tremors in patients with PD. Study outcomes were extracted, and evidence was synthesized narratively.

RESULTS

A total of six modalities described in six studies were included in this systematic review. Out of the six interventions, the tremor's glove and electrical stimulation showed significant improvements in root mean square angular velocity (59% and 43.8%, respectively) and UPDRS tremor score (P < 0.05 for both). Also, eccentric exercises were associated with significant reductions in the mean resting tremor amplitude (P < 0.05). These data were dependent on single studies; therefore, a meta-analysis was not feasible.

CONCLUSION

Several physical therapy interventions, such as electrical stimulation, exercises, transcranial low voltage pulsed electromagnetic fields, weights, and virtual reality showed promising results in reducing hand tremors. However, this evidence was based on a limited number of included studies, and more RCTs with larger sample sizes are required to confirm the efficacy of these interventions.

Pulsed electric fields stimulate microglial transmitter release of VEGF, IL-8 and GLP-1 and activate endothelial cells through paracrine signaling

As action potentials propagate along an axon, pulsed extracellular electric fields (E-fields) are induced. We investigated the role of E-fields in activating microglia cells and affecting capillary function and found that E-fields control human microglia secretions in concert with purinergic factors. We generated E-fields by applying transcranial pulsed electromagnetic fields (T-PEMF) identical to those appearing outside neurons as action potentials propagate. T-PEMF alone enhanced mRNA synthesis for VEGF, IL-8, IL-6 and the proglucagon gene as well as the PC1/3 enzyme that cleaves the proglucagon protein to glucagon and GLP-1 proteins. We found that T-PEMF enhanced secretion from microglia of VEGF, IL-8 and GLP-1 proteins having angiogenic and proliferative profiles. Interestingly, T-PEMF and purinergic transmitters together enhanced secretions confirming synergy between their actions. ATP also induced nitric oxide (NO) syntheses in distinct locations in the nucleus and the mRNA synthesis for the responsible iNOS was reduced by T-PEMF. When the microglia-secretory fluid was added to brain endothelial cells we saw vivid Ca²⁺ signaling and enhanced transcription of mRNA for IL-8 and VEGF. Our previous work shows that applying T-PEMF to the human brain provides up to 60% remission for patients with refractory depressions within 8 weeks and improvements for Parkinson patients. Thus, physiological E-fields activate microglia, work synergistically with neurotransmitters, and cause paracrine secretions which cause activation of capillaries. Application of these E-Fields is effective for treating refractory depressions and appear promising for treating neurodegenerative brain diseases.

Long-term treatment with transcranial pulsed electromagnetic fields improves movement speed and elevates cerebrospinal erythropoietin in Parkinson's disease

Background

Parkinson’s disease is characterized by motor dysfunctions including bradykinesia. In a recent study, eight weeks of daily transcranial stimulation with bipolar pulsed electromagnetic fields improved functional rate of force development and decreased inter-hand tremor coherence in patients with mild Parkinson’s disease.

Objective

To investigate the effect of long-term treatment with transcranial bipolar pulsed electromagnetic fields on motor performance in terms of movement speed and on neurotrophic and angiogenic factors.

Methods

Patients diagnosed with idiopathic Parkinson’s disease had either daily 30-min treatment with bipolar (±50 V) transcranial pulsed electromagnetic stimulation (squared pulses, 3ms duration) for three eight-week periods separated by one-week pauses (T-PEMF group) (n = 16) or were included in a PD-control group (n = 8). Movement speed was assessed in a six-cycle sit-to-stand task performed on a force plate. Cerebrospinal fluid and venous blood were collected and analyzed for erythropoietin and vascular endothelial growth factor.

Results

Major significant improvement of movement speed compared to the natural development of the disease was found (p = 0.001). Thus, task completion time decreased gradually during the treatment period from 10.10s to 8.23s (p<0.001). The untreated PD-control group did not change (p = 0.458). The treated group did not differ statistically from that of a healthy age matched reference group at completion of treatment. Erythropoietin concentration in the cerebrospinal fluid also increased significantly in the treated group (p = 0.012).

Conclusion

Long-term treatment with transcranial bipolar pulsed electromagnetic fields increased movement speed markedly and elevated erythropoietin levels. We hypothesize that treatment with transcranial bipolar pulsed electromagnetic fields improved functional performance by increasing dopamine levels in the brain, possibly through erythropoietin induced neural repair and/or protection of dopaminergic neurons.

The role of magnetic fields in neurodegenerative diseases

The term neurodegenerative diseases include a long list of diseases affecting the nervous system that are characterized by the degeneration of different neurological structures. Among them, Alzheimer disease (AD), Parkinson disease (PD), and amyotrophic lateral sclerosis (ALS) are the most representative ones. The vast majority of cases are sporadic and results from the interaction of genes and environmental factors in genetically predisposed individuals. Among environmental conditions, electromagnetic field exposure has begun to be assessed as a potential risk factor for neurodegeneration. In this review, we discuss the existing literature regarding electromagnetic fields and neurodegenerative diseases. Epidemiological studies in AD, PD, and ALS have shown discordant results; thus, a clear correlation between electromagnetic exposure and neurodegeneration has not been demonstrated. In addition, we discuss the role of electromagnetic radiation as a potential non-invasive therapeutic strategy for some neurodegenerative diseases, particularly for PD and AD.

The influence of pulsed electromagnetic field therapy (PEMFT) on cutaneous blood flow in healthy volunteers1

BACKGROUND

The biophysical interaction induced by low energy pulsed electromagnetic field therapy (PEMFT) on the capillary microcirculation is not well understood. Several studies indicate a significant effect of PEMFT in patients with chronic medical conditions.

OBJECTIVE

The aim of this study was to evaluate the influence of PEMFT on skin microcirculation in healthy volunteers.

METHODS

15 healthy participants were included. Nine PEMF treatments were applied over three weeks in an 48-hour interval. The PEMFT system (BEMER) was placed beneath one of the participants' leg with the contralateral side serving as a control. A forty-minute application period was preceded by a 10-minute resting phase. Measuring was done using two Laser Doppler probes (LEA) placed on each anterior lateral thigh.

RESULTS

All outcome parameters including flow, mixed venous oxygen saturation and relative venous hemoglobin showed a significant increase during the experiment when compared to the baseline values of the resting phase in both groups (p < 0.01). Comparing both groups, the measurement values during the experiment did not differ (p > 0.05) except for higher flow values in the control group (P = 0.03). Over time, baseline values of both groups showed no significant difference (p > 0.05).

CONCLUSION

We found a significant increase of all measurement parameters during the study compared to the baseline values with no difference between the PEMF and control group.

The influence of posture duration on hand tremor during tasks with attention-distraction in persons with Parkinson's disease

BACKGROUND

Tremor is one of the hallmarks and most bothersome symptoms in Parkinson's disease (PD). The classical PD tremor is present at rest, but postural tremor also occurs. PD tremor can be continuous or intermittently present and can have a re-emergent nature. The tremor intensity is affected by attention and stress level. Observations of PD tremor have indicated increased tremor intensity with time during 30-s tremor assessments. This phenomenon has not previously been studied systematically. Thus, in order to contribute to our understanding of the mechanisms associated with PD tremor, our aim was to investigate the influence of time during a posture holding and a resting task on hand tremor characteristics in persons with PD compared to healthy peers.

METHOD

Fifty persons with PD and at least one tremoring hand (tremor intensity exceeding mean + 2SD of a healthy reference group (REF), N = 40) were included from a clinical trial population. Hand accelerations in a rest and postural condition were measured in 30-s assessments while the participants performed a self-paced simple subtraction task with eyes closed to standardize attention without inducing stress. Tremor intensity, maximal power, frequency of maximal power and tremor onset time was calculated for three consecutive 10-s time intervals.

RESULTS

Tremor intensity and maximal power increased significantly during the 30-s recording in the PD-group in both conditions (1st-3rd time-interval, tremor intensity: rest + 65% p < 0.0001, postural + 55% p < 0.0001; maximal power: rest + 93% p < 0.0001, postural + 82% p < 0.001). No effect of time was found on frequency of maximal power in the PD-group or on any effect measure in the REF-group.

CONCLUSION

Tremor intensity and maximal power increased with time in the PD-group during 30-s tasks, while no change with time was found in the REF-group. In contrast, frequency of maximal power remained unchanged, which may suggest that the same neural circuits were responsible for the tremor generation throughout the tasks. The increase in tremor intensity and maximal power could not solely be explained by re-emergence of tremor. This suggests an increasing or gradually more synchronized cortico-spinal drive throughout the tasks. However, this requires further studies to determine.