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.

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.

BACKGROUND: Parkinson's disease (PD) tremor comprises asymmetric rest and postural tremor with unilateral onset. Tremor intensity can be amplified by stress and reduced by attention, and the medical treatment is complex. Mirror movements and unintentional synchronization of bimanual movements, possibly caused by insufficient inhibition of inter-hemispheric crosstalk, have been reported in PD, indicating a lag of lateralization. Potential neuroprotective effects of pulsed electromagnetic fields (PEMF) have been reported in-vitro and in rodents, as have influences of PEMF on human tremor. The aim was to investigate the effect of 8 weeks daily transcranial PEMF treatment (T-PEMF) of persons with PD on rest and postural hand tremor characteristics and on inter-hand coherence. METHODS: Hand accelerations of 50 PD participants with uni- or bilateral tremor participating in a clinical trial were analysed. A rest and postural tremor task performed during serial subtraction was assessed before and after 8 weeks of T-PEMF (30 min/day, 50 Hz, ±50 V, 3 ms squared pulses) or placebo treatment (sham stimulation 30 min/day). Forty matched healthy persons (no treatment) were included as reference. Intensity and inter-hand coherence related measures were extracted. RESULTS: The T-PEMF treatment decreased the inter-hand coherence in the PD group with unilateral postural tremor. The PD group with unilateral postural tremor was less clinically affected by the disease than the PD group with bilateral postural tremor. However, no differences between T-PEMF and placebo treatment on either intensity related or coherence related measures were found when all persons with PD were included in the analyses. The peak power decreased and the tremor intensity tended to decrease in both treatment groups. CONCLUSIONS: Eight weeks of T-PEMF treatment decreased inter-hand coherence in the PD group with unilateral postural tremor, while no effects of T-PEMF treatment were found for the entire PD group. The unilateral postural tremor group was less clinically affected than the bilateral postural tremor group, suggesting that early treatment initiation may be beneficial. In theory, a reduced inter-hand coherence could result from a neuronal treatment response increasing inter-hemispheric inhibition. However, this requires further studies to determine. Studies of even longer treatment periods would be of interest. TRIAL REGISTRATION: ClinicalTrials.gov , NCT02125032. Registered 29 April 2014, https://clinicaltrials.gov/ct2/show/NCT02125032?term=NCT02125032&rank=1.

The Hawthorne effect as a pre-placebo expectation in Parkinsons disease patients participating in a randomized placebo-controlled clinical study.

BACKGROUND: The Hawthorne effect on clinical studies in Parkinson's disease has not been thoroughly investigated. Evidently the Hawthorne effect may have impact on study outcomes acting as a 'pre-placebo' effect in the recruitment phase, hence before inclusion. AIM: The aim of this study was to discuss the Hawthorne effect in relation to clinical and self-reported outcome measures in a randomized clinical study in the recruitment phase and during the study. METHODS: Data from 97 participants with Parkinson's disease treated with Transcranial Pulsed Electromagnetic Fields were applied, randomized to an active (n = 49) or a placebo treated group (n = 48). The participants received one home treatment session, for eight consecutive weeks. Outcome measures were the Unified Parkinson's Disease Rating Scale, The 39-item Parkinson's Disease Questionnaire and the WHO-5. RESULTS: No difference in treatment effect between the two groups was found pertaining the Unified Parkinson's Disease Rating Scale. No difference in treatment effect between the two groups was found pertaining the 39-item Parkinson's Disease Questionnaire, apart from the dimension mobility. No difference in treatment effect between the two groups was found pertaining the WHO-5 scale. CONCLUSIONS: The Hawthorne effect may have caused a 'pre-placebo' effect on the outcome measures even before obtaining baseline outcomes measures. This study may have been particularly prone to a Hawthorne effect due to the intense contact with the participants before and during the study. Moreover, the Hawthorne effect should not be viewed upon as a single entity but rather as entities affecting outcome measures throughout the full study period.

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.

Evaluating psychiatric symptoms in Parkinson's Disease by a clinimetric analysis of the Hopkins Symptom Checklist (SCL-90-R).

Although psychiatric comorbidity in Parkinson's Disease (PD) has often been studied, the individual psychiatric symptoms have rarely been evaluated from a clinimetric point of view in an attempt to measure how much the symptoms have been bothering or distressing the PD patients. The current study is therefore aimed at evaluating from a clinimetric viewpoint the severity of psychiatric symptoms affecting PD patients by using the Hopkins Symptom Checklist (SCL-90-R) to show its measurement-driven construct validity (scalability). The conventional nine SCL-90-R subscales (somatization, obsessive-compulsive, interpersonal sensitivity, depression, anxiety, hostility, phobic anxiety, paranoid ideas, and psychoticism), as well as the clinical most valid subscales from the SCL-28 version (depression, anxiety, interpersonal sensitivity, and neurasthenia) were analysed according to a clinimetric approach by comparing PD patients with a control group from a general population study. Scalability was tested by the non-parametric item response theory model by use of a Mokken analysis. Among the various SCL-90-R or SCL-28 subscales we identified from the clinimetric analysis that the somatization, anxiety, phobic anxiety, psychoticism, and neurasthenia (apathy), as well as the SCL-90-R GSI, were the most impaired psychiatric syndromes reaching a clinically significant effect size above 0.80, whereas the total SCL-28 GSI obtained an effect size of just 0.80. Our clinimetric analysis has shown that patients with PD not only are bothered with diverse somatic symptoms, but also with specific secondary psychiatric comorbidities which are clinically severe markers of impairment in the day-to-day function implying a negative cooping approach.

Effect of transcranial pulsed electromagnetic fields (T-PEMF) on functional rate of force development and movement speed in persons with Parkinson's disease: A randomized clinical trial.

BACKGROUND: 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. OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Effects of Long-Term Treatment with T-PEMF on Forearm Muscle Activation and Motor Function in Parkinson's Disease.

Bipolar pulsed electromagnetic stimulation applied to the brain (T-PEMF) is a non-pharmacological treatment which has been shown to stimulate nerve growth, attenuate nerve abnormalities, and improve microcirculation. We report on a 62-year-old, medically well-treated man with idiopathic Parkinson's disease. He was treated with T-PEMF, 30 min per day for three 8-week periods separated by two 1-week breaks. The disease made his handwriting impossible to read mainly due to small letters and lack of fluency. Forearm EMG measured during standardized conditions showed an involuntary spiky EMG pattern with regular burst activity (on his left side) at baseline. The intervention normalized the handwriting and forearm EMG. The UPDRS-motor score decreased from 25 to 17, and UPDRS-II-handwriting decreased from a pre-intervention value of 3 to 0 after the intervention. Finally, the patient reported improved fine motor function, less muscle stiffness, less muscle cramps and tingling, and less fatigue during the day in response to the T-PEMF treatment. The improved handwriting lasted for approximately 3 months after the treatment. Our results should be considered as preliminary, and large-scale, controlled studies are recommended to elucidate the therapeutic potential of long-term treatment with T-PEMF.

Somatization in Parkinson's Disease: A systematic review.

The current systematic review study is aimed at critically analyzing from a clinimetric viewpoint the clinical consequence of somatization in Parkinson's Disease (PD). By focusing on the International Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a comprehensive electronic literature research strategy on ISI Web-of-Science, PsychINFO, PubMed, EBSCO, ScienceDirect, MEDLINE, Scopus, and Google Scholar databases. Out of 2.926 initial records, only a total of 9 studies were identified as clearly relevant and analyzed in this systematic review. The prevalence of somatization in PD has been found to range between 7.0% and 66.7%, with somatoform disorders acting as clinical factor significantly contributing to predict a progressive cognitive impairment. We highlighted that somatization is a highly prevalent comorbidity affecting PD. However, the clinical consequence of such psychiatric symptom should be further evaluated by replacing the clinically inadequate diagnostic label of psychogenic parkinsonism with the psychosomatic concept of persistent somatization as conceived by the Diagnostic Criteria for Psychosomatic Research (DCPR).