The Rationale for Exercise in the Management of Pain in Parkinson's Disease

A Mixed Methods Approach to Explore the Experience of Pain and Its Management in People with Parkinson's Disease

Introduction

Pain in Parkinson's disease (PD) is common but poorly understood, with most research to date taking a mechanistic approach. This mixed methods study takes a broader biopsychosocial approach to assess and describe contributors of pain and explore pain management and the relationship between pain and physical activity in people with PD (PwPD) and chronic pain.

Methods

A structured survey evaluated respondents' contributors of pain using standardized, self-report assessments of the following: pain, peripheral neuropathy, central nociplastic change, emotional dysregulation or pathology, and maladaptive cognitions. Semistructured individual interviews were conducted with purposively sampled survey participants and analyzed using inductive thematic analysis.

Results

Eighty-nine PwPD (mean age 67 years, 55% female) completed the survey. The most common pain contributors were maladaptive cognitions (62%), central nociplastic change (49%), and emotional dysregulation (44%). Approaches to pain management and the response to physical activity were variable within and across individuals with different pain contributors. Four themes emerged from interviews with 24 participants: (1) causative perceptions of pain are diverse; (2) sense of control influences disease acceptance and exercise self-efficacy; (3) belief in the value of therapy; and (4) pain as the unspoken PD symptom. Physical activity was used by PwPD for pain management; however, the relationship between pain and physical activity varied based on sense of control.

Conclusions

Clinicians should screen for pain and assess its contributors to provide individualized, multidimensional pain management that considers the biological, psychological, and social factors of pain in PwPD. It is plausible that such an approach would promote a better sense of control for PwPD.

Pain and the Non-Pharmacological Management of Pain in People with Parkinson's Disease

Pain is a distressing and universal experience, yet everyone's pain experience is influenced by a complex array of biological, psychological, and social factors. For people with Parkinson's disease (PwP), these biopsychosocial factors include neurodegeneration and the psychological and social factors that accompany living with a chronic, neurodegenerative condition in addition to the factors experienced by those in the general population (e.g., living with co-morbidities such as osteoarthritis). The way these factors influence each individual is likely to determine which pain management strategies are optimal for them. This review first describes pain and the biopsychosocial model of pain. It explores how pain is classified in Parkinson's disease (PD) and describes the three main types of pain: nociceptive, neuropathic, and nociplastic pain. This background provides context for a discussion of non-pharmacological pain management strategies that may aid in the management of pain in PwP; exercise, psychological strategies, acupuncture and massage. While there is little PD-specific research to inform the non-pharmacological management of pain, findings from current PD research are combined with that from chronic pain research to present recommendations for clinical practice. Recommendations include assessment that incorporates potential biopsychosocial contributors to pain that will then guide a holistic, multi-modal approach to management. As exercise provides overall benefits for PwP, those with chronic pain should be carefully monitored with exercise prescribed and adjusted accordingly. Research is needed to develop and evaluate multi-modal approaches to pain management that are delivered in a biopsychosocial framework.

Exercise as medicine in Parkinson's disease

Parkinson's disease (PD) is an incurable and progressive neurological disorder leading to deleterious motor and non-motor consequences. Presently, no pharmacological agents can prevent PD evolution or progression, while pharmacological symptomatic treatments have limited effects in certain domains and cause side effects. Identification of interventions that prevent, slow, halt or mitigate the disease is therefore pivotal. Exercise is safe and represents a cornerstone in PD rehabilitation, but exercise may have even more fundamental benefits that could change clinical practice. In PD, the existing knowledge base supports exercise as (1) a protective lifestyle factor preventing the disease (ie, primary prevention), (2) a potential disease-modifying therapy (ie, secondary prevention) and (3) an effective symptomatic treatment (ie, tertiary prevention). Based on current evidence, a paradigm shift is proposed, stating that exercise should be individually prescribed as medicine to persons with PD at an early disease stage, alongside conventional medical treatment.

What is available to support pain management in Parkinson's: a scoping review protocol

OBJECTIVE

A scoping review will be undertaken to examine and map the available evidence that has been produced in relation to pain management in Parkinson's, with a focus on behavioural interventions, resources and/or how professionals support people with Parkinson's self-management of pain.

METHODS

This review will be based on the methodological framework given by Arksey and O'Malley's (2005), including enhancements by Levac et al., Peters et al. and the Joanna Briggs Institute. We will include studies from PubMed, SCOPUS, CINAHL, MEDLINE Web of Science, APA PsycINFO and ASSIA from January, 2010 onwards. Both quantitative and qualitative data will be analysed separately to identify the characteristics of support for pain management available, orientation of the approach and any identifiable behaviour change components and their outcomes. The COM-B behaviour change model and Theoretical Domains Framework will provide a theoretical framework for synthesising evidence in this review.

CONCLUSION

This scoping review will help to explore studies focusing on the evidence supporting a range of interventions relating to the management of pain experienced by people living with Parkinson's. The focus will be on describing what is available to support self-management, identify what behaviour change components have been used and their effectiveness, identify barriers and enablers to pain management and explore gaps in current provision of pain management. This review will identify implications and priorities for the follow-up phases to the larger 'Pain in Parkinson's' Project which is designed to support clinicians and individuals living with Parkinson's.

Research trends and hotspots of neuropathic pain in neurodegenerative diseases: a bibliometric analysis

Background

Neuropathic pain is caused by a neurological injury or disease and can have a significant impact on people's daily lives. Studies have shown that neuropathic pain is commonly associated with neurodegenerative diseases. In recent years, there has been a lot of literature on the relationship between neuropathic pain and neurodegenerative diseases. However, bibliometrics is rarely used in analyzing the general aspects of studies on neuropathic pain in neurodegenerative diseases.

Methods

The bibliometric analysis software CiteSpace and VOSviewer were used to analyze the knowledge graph of 387 studies in the Science Citation Index Expanded of the Web of Science Core Collection Database.

Results

We obtained 2,036 documents through the search, leaving 387 documents after culling. 387 documents were used for the data analysis. The data analysis showed that 330 papers related to neuropathic pain in neurodegenerative diseases were published from 2007-2022, accounting for 85.27% of all published literature. In terms of contributions to the scientific study of neuropathic pain, the United States is in the top tier, with the highest number of publications, citations, and H-indexes.

Conclusion

The findings in our study may provide researchers with useful information about research trends, frontiers, and cooperative institutions. Multiple sclerosis, Parkinson's disease, and Alzheimer's disease are the three most studied neurodegenerative diseases. Among the pathological basis of neurodegenerative diseases, microglia-regulated neuroinflammation is a hot research topic. Deep brain stimulation and gamma knife radiosurgery are two popular treatments.

The mechanism of exercise for pain management in Parkinson's disease

The research and clinical applications of exercise therapy to the treatment of Parkinson's disease (PD) are increasing. Pain is among the important symptoms affecting the daily motor function and quality of life of PD patients. This paper reviewed the progress of research on different exercise therapies for the management of pain caused by PD and described the role and mechanism of exercise therapy for pain relief. Aerobic exercise, strength exercise, and mind-body exercise play an effective role in pain management in PD patients. The pain suffered by PD patients is divided into central neuropathic, peripheral neuropathic, and nociceptive pain. Different types of pain may coexist with different mechanistic backgrounds and treatments. The analgesic mechanisms of exercise intervention in PD-induced pain include altered cortical excitability and synaptic plasticity, the attenuation of neuronal apoptosis, and dopaminergic and non-dopaminergic analgesic pathways, as well as the inhibition of oxidative stress. Current studies related to exercise interventions for PD-induced pain suffer from small sample sizes and inadequate research of analgesic mechanisms. The neurophysiological effects of exercise, such as neuroplasticity, attenuation of neuronal apoptosis, and dopaminergic analgesic pathway provide a sound biological mechanism for using exercise in pain management. However, large, well-designed randomized controlled trials with improved methods and reporting are needed to evaluate the long-term efficacy and cost-effectiveness of exercise therapy for PD pain.

Sensorimotor Integration and Pain Perception: Mechanisms Integrating Nociceptive Processing. A Systematic Review and ALE-Meta Analysis

Pain treatment services and clinical indicators of pain chronicity focus on afferent nociceptive projections and psychological markers of pain perception with little focus on motor processes. Research supports a strong role for the motor system both in terms of pain related disability and in descending pain modulation. However, there is little understanding of the neurological regions implicated in pain-motor interactions and how the motor and sensory systems interact under conditions of pain. We performed an ALE meta-analysis on two clinical cohorts with atypical sensory and motor processes under conditions of pain and no pain. Persons with sensory altered processing (SAP) and no pain presented with greater activity in the precentral and supplementary motor area relative to persons with self-reported pain. In persons with motor altered processing (MAP), there appeared to be a suppression of activity in key pain regions such as the insula, thalamus, and postcentral gyrus. As such, activation within the motor system may play a critical role in dampening pain symptoms in persons with SAP, and in suppressing activity in key pain regions of the brain in persons with MAP. Future research endeavors should focus on understanding how sensory and motor processes interact both to understand disability and discover new treatment avenues.

A Survey of People With Parkinson's and Their Carers: The Management of Pain in Parkinson's

BACKGROUND

Pain in Parkinson's is problematic but under treated in clinical practice. Healthcare professionals must understand the impact of pain in Parkinson's and patient preferences for management.

OBJECTIVE

To understand the impact of pain in Parkinson's and to understand current management and preferences for pain management.

METHODS

We conducted a national survey with 115 people with Parkinson's (PwP) and 10 carers. Both closed and open questions were used. The questions focused on how pain affected the individual, healthcare professional involvement in supporting pain management, current pain management strategies and views on future pain management interventions. We used descriptive statistics to summarize closed responses and thematic analysis to summarize open question responses.

RESULTS

70% of participants reported pain impacted their daily life. Pain had a multifactorial impact on participants, affecting movement, mood and quality of life. Improved pain management was viewed to have the potential to address each of these challenges. Pain affected a number of different sites, with low back pain and multiple sites being most frequently reported. Exercise was the most frequently noted strategy (38%) recommended by healthcare professionals for pain management. PwP would value involvement from healthcare professionals for future pain management, but also would like to self-manage the condition. Medication was not suggested as a first line strategy.

CONCLUSIONS

Despite reporting engagement in some strategies to manage pain, pain still has a wide-ranging impact on the daily life of PwP. Results from this survey highlight the need to better support PwP to manage the impact of pain.

Minimal clinically important difference of the King's Parkinson's disease Pain Scale

OBJECTIVE

Pain is a common and debilitating symptom of Parkinson's disease (PD) and has no specific treatment. King's Parkinson's disease Pain Scale (KPPS) is the only specific scale for pain measurement in PD with established psychometric properties. The minimal clinically important difference (MCID) of KPPS, an important parameter for the design and interpretation of therapeutic interventions, has not yet been measured. The aim of our study was to assess the MCID of KPPS.

METHODS

Two hundred and seven PD patients were evaluated by KPPS before and after receiving the intervention. The Clinical Global Impression of Improvement Scale was used as an anchor, and a Receiver Operating Characteristic (ROC) curve was used to determine the optimal MCID cut-off point for KPPS. The distribution-based approach applied one-third standard deviation (SD), 0.5 SD, and one standard error of measurement (SEM) of the total score of KPPS to determine the MCID.

RESULTS

The MCID achieved from the ROC curve was 3 points (sensitivity: 74.4%; specificity: 81.9%). For the distribution-based method, the MCIDs corresponding to 0.3 SD, 0.5 SD, and one SEM were 5.65, 9.41, and 2.54 points, respectively.

CONCLUSION

KPPS is a valid scale for measuring pain in PD with demonstrable MCID. IMPLICATIONS FOR REHABILITATIONThe King's Parkinson's disease Pain Scale (KPPS) is a valid scale for measuring pain in patients with Parkinson's disease (PD) with demonstrable minimal clinically important difference (MCID).The MCID obtained in the current study will assist clinicians and researchers when interpreting KPPS change score to determine clinically meaningful changes of pain in both PD progression and response to interventions.

Physical Activity and Its Diurnal Fluctuations Vary by Non-Motor Symptoms in Patients with Parkinson's Disease: An Exploratory Study

Background: This exploratory study investigated the association between non-motor symptoms (NMS) and both physical activity and diurnal activity patterns in patients with Parkinson’s disease (PwPD). Methods: Participants included PwPD with modified Hoehn and Yahr stages 1−3. The presence of NMS was assessed with Movement Disorder Society-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) Part I. Physical activity was measured using a waist-mounted triaxial accelerometer. Logistic regression analyses evaluated associations between NMS and physical activity; furthermore, diurnal fluctuation in physical activity due to NMS was examined by ANCOVA. Results: Forty-five PwPD were included in the study. Among the domains of NMS, pain and other sensations (OR, 8.36; 95% CI, 1.59−43.94) and fatigue (OR, 14.26; 95% CI, 1.85−109.90) were associated with low daily step count (<4200 steps/day). Analysis by time of day showed no characteristic variability in physical activity but had constant effect sizes for pain and other sensations (p = 0.20, ES = 0.36) and fatigue (p = 0.08, ES = 0.38). Conclusion: Our exploratory study suggested that PwPD with pain and other sensations and fatigue recorded lower step counts than their asymptomatic counterparts. Therefore, PwPD with pain and fatigue may need more support in promoting physical activity.

The accuracy of self-report logbooks of adherence to prescribed home-based exercise in Parkinson's disease

PURPOSE

This study compared self-report logbooks of exercise performance to objective measures of performance to determine the accuracy of and patterns of misreporting in self-report logbooks in people with Parkinson's disease.

MATERIALS AND METHODS

Fifteen participants from the intervention arm of a randomized control trial were prescribed a minimally supervised, 12-week, home-based upper limb exergame program (ACTRN 12614001048673). The exergame system provided an objective electronic measure of adherence for comparison with self-report logbooks.

RESULTS

Logbooks showed excellent to good accuracy of overall reported adherence to prescribed sessions (Intraclass correlation (ICC) = 0.83) and games (ICC 0.71). Logbooks were also a good to fair representation of weekly adherence across participants for both sessions (ICC 0.66) and games (ICC 0.56). Individual participant ICCs ranged from minimal to perfect agreement between logbooks and electronic records (ICC sessions range: -0.02 to 1; games range: -0.24 to 0.99). The pattern of logbook reporting suggested some participants were biasing entries to match prescribed exercise.

CONCLUSIONS

Self-report logbooks may provide an accurate measure of overall adherence. However, the accuracy of individual logbooks was highly variable indicating caution is needed in using self-report measures to assess individual adherence in intervention studies and for clinical decision making. Clinical Trial Registration: Registered in Australia and New Zealand Clinical Trials Registry (https://www.anzctr.org.au/): Registration number: ACTRN12614001048673.Implications for rehabilitationAdherence to prescribed unsupervised exercise is usually self-reported.Self-reported logbooks gave a good to excellent indication of exercise adherence overall when compared to electronically captured records for a group of participants with mild to moderate Parkinson's disease.There were high levels of variability in the accuracy of individual logbooks with a tendency to record prescribed rather than actual exercise.Logbooks may be accurate to monitor group adherence, but caution is required when using them to assess an individual's adherence to an exercise prescription.

Non-pharmacological therapies for pain management in Parkinson's disease: A systematic review

Among the various non-motor symptoms of Parkinson's disease (PD), pain is often cited as the most common and debilitating feature. Currently, the literature contains gaps in knowledge with respect to the various forms of treatment available, particularly non-pharmacological therapies. Thus, the purpose of this systematic review is to provide an examination of the literature on non-pharmacological therapies for pain in PD. We compared the findings of research articles indexed within various literature databases related to non-pharmacological treatments of pain in PD patients. Our review identified five major non-pharmacological methods of pain therapy in PD: acupuncture, hydrotherapy, massage therapy, neuromodulation, and exercise. Treatments such as exercise therapy found a reduction in pain perception due to various factors, including the analgesic effects of neurotransmitter release during exercise and increased activity leading to a decrease in musculoskeletal rigidity and stiffness. By the same token, hydrotherapy has been shown to reduce pain perception within PD patients, with authors often citing a combined treatment of exercise and hydrotherapy as an effective treatment for pain management. Multiple methods of neurostimulation were also observed, including deep brain stimulation and spinal cord stimulation. Deep brain stimulation showed efficacy in alleviating certain pain types (dystonic and central), while not others (musculoskeletal). Hence, patients may consider deep brain stimulation as an additive procedure for their current treatment protocol. On the other hand, spinal cord stimulation showed significant improvement in reducing VAS scores for pain. Finally, although the literature on massage therapy and acupuncture effectiveness on pain management is limited, both have demonstrated a reduction in pain perception, with common reasons such as tactile stimulation and release of anti-nociceptive molecules in the body. Although literature pertaining to non-pharmacological treatments of pain in PD is sparse, there is copious support for these treatments as beneficial to pain management. Further exploration in the form of clinical trials is warranted to assess the efficacy of such therapies.

Exercise protects synaptic density in a rat model of Parkinson's disease

BACKGROUND

Parkinson's disease (PD) is characterized by Lewy body and neurite pathology associated with dopamine terminal dysfunction. Clinically, it is associated with motor slowing, rigidity, and tremor. Postural instability and pain are also features. Physical exercise benefits PD patients - possibly by promoting neuroplasticity including synaptic regeneration.

OBJECTIVES

In a parkinsonian rat model, we test the hypotheses that exercise: (a) increases synaptic density and reduces neuroinflammation and (b) lowers the nociceptive threshold by increasing μ-opioid receptor expression.

METHODS

Brain autoradiography was performed on rats unilaterally injected with either 6-hydroxydopamine (6-OHDA) or saline and subjected to treadmill exercise over 5 weeks. [³H]UCB-J was used to measure synaptic vesicle glycoprotein 2A (SV2A) density. Dopamine D2/3 receptor and μ-opioid receptor availability were assessed with [³H]Raclopride and [³H]DAMGO, respectively, while neuroinflammation was detected with the 18kDA translocator protein (TSPO) marker [³H]PK11195. The nociceptive threshold was determined prior to and throughout the exercise protocol.

RESULTS

We confirmed a dopaminegic deficit with increased striatal [³H]Raclopride D2/3 receptor availability and reduced nigral tyrosine hydroxylase immunoreactivity in the ipsilateral hemisphere of all 6-OHDA-injected rats. Sedentary rats lesioned with 6-OHDA showed significant reduction of ipsilateral striatal and substantia nigra [³H]UCB-J binding while [³H]PK11195 showed increased ipsilateral striatal neuroinflammation. Lesioned rats who exercised had higher levels of ipsilateral striatal [³H]UCB-J binding and lower levels of neuroinflammation compared to sedentary lesioned rats. Striatal 6-OHDA injections reduced thalamic μ-opioid receptor availability but subsequent exercise restored binding. Exercise also raised thalamic and hippocampal SV2A synaptic density in 6-OHDA lesioned rats, accompanied by a rise in nociceptive threshold.

CONCLUSION

These data suggest that treadmill exercise protects nigral and striatal synaptic integrity in a rat lesion model of PD - possibly by promoting compensatory mechanisms. Exercise was also associated with reduced neuroinflammation post lesioning and altered opioid transmission resulting in an increased nociceptive threshold.

Perceived walking difficulties in Parkinson's disease - predictors and changes over time

BACKGROUND

People with Parkinson's disease (PD) have described their walking difficulties as linked to activity avoidance, social isolation, reduced independence and quality of life. There is a knowledge gap regarding predictive factors of perceived walking difficulties in people with PD. Such knowledge could be useful when designing intervention studies. This study aimed to investigate how perceived walking difficulties evolve over a 3-year period in people with PD. A specific aim was to identify predictive factors of perceived walking difficulties.

METHODS

One hundred forty-eight people with PD (mean age 67.9 years) completed the Generic Walk-12 (Walk-12G) questionnaire (which assesses perceived walking difficulties) at both baseline and the 3-year follow-up. Paired samples t-test was used for comparing baseline and follow-up mean scores. Multivariable linear regression analyses were used to identify predictive factors of perceived walking difficulties.

RESULTS

Perceived walking difficulties increased after 3 years: mean Walk-12G score 14.8 versus 18.7, p < 0.001. Concerns about falling was the strongest predictor (β = 0.445) of perceived walking difficulties, followed by perceived balance problems while dual tasking (β = 0.268) and pain (β = 0.153). Perceived balance problems while dual tasking was the strongest predictor (β = 0.180) of a change in perceived walking difficulties, followed by global cognitive functioning (β = - 0.107).

CONCLUSIONS

Perceived walking difficulties increase over time in people with PD. Both personal factors (i.e. concerns about falling) and motor aspects (i.e. balance problems while dual tasking) seem to have a predictive role. Importantly, our study indicates that also non-motor symptoms (e.g. pain and cognitive functioning) seem to be of importance for future perceived walking difficulties. Future intervention studies that address these factors need to confirm their preventative effect on perceived walking difficulties.

Evidence for Early and Regular Physical Therapy and Exercise in Parkinson's Disease

Advances in medical management of Parkinson's disease (PD) have resulted in living longer with disability. Although disability worsens over the course of the disease, there are signs of disability even in the early stages. Several studies reveal an early decline in gait and balance and a high prevalence of nonmotor signs in the prodromal period that contribute to early disability. There is a growing body of evidence revealing the benefits of physical therapy and exercise to mitigate motor and nonmotor signs while improving physical function and reducing disability. The presence of early disability coupled with the benefits of exercise suggests that physical therapy should be initiated earlier in the disease. In this review, we present the evidence revealing early disability in PD and the effectiveness of physical therapy and exercise, followed by a discussion of a secondary prevention model of rehabilitation to reduce early disability and optimize long-term outcomes.

Understanding the influence of pain and fatigue on physical performance, fear of falling and falls in people with Parkinson's disease: a pilot study

Objective: Pain and fatigue are highly prevalent debilitating symptoms in Parkinson's disease (PD), however, their relationship with physical performance, fear of falling (FOF) and falls is not clear. We aim in this pilot study to investigate the relationship of pain and fatigue with physical performance, FOF and falls in people with Parkinson's disease (PwPD). Materials & methods: 53 PD patients were assessed for fall history, physical performance, FOF, pain and fatigue. Results: Pain and fatigue are significantly associated with physical performance and FOF (p ≤ 0.002). Pain and fatigue were different between fallers and non-fallers (p < 0.5), but only fatigue could distinguish fallers from non-fallers (area under the receiver operating characteristics curve = 0.81; p < 0.0001). Conclusion: This pilot study indicated that FOF in PwPD is significantly associated with pain and fatigue. Furthermore, fatigue level is related to fall history. By addressing pain and fatigue, we may ameliorate the deterioration of FOF and falls in PwPD.

Chasing Protection in Parkinson's Disease: Does Exercise Reduce Risk and Progression?

Exercise may be the most commonly offered yet least consistently followed therapeutic advice for people with Parkinson’s disease (PD). Epidemiological studies of prospectively followed cohorts have shown a lower risk for later developing PD in healthy people who report moderate to high levels of physical activity, and slower rates of motor and non-motor symptom progression in people with PD who report higher baseline physical activity. In animal models of PD, exercise can reduce inflammation, decrease α-synuclein expression, reduce mitochondrial dysfunction, and increase neurotrophic growth factor expression. Randomized controlled trials of exercise in PD have provided clear evidence for short-term benefits on many PD measurements scales, ranging from disease severity to quality of life. In this review, we present these convergent epidemiological and laboratory data with particular attention to translationally relevant features of exercise (e.g., intensity requirements, gender differences, and associated biomarkers). In the context of these findings we will discuss clinical trial experience, design challenges, and emerging opportunities for determining whether exercise can prevent PD or slow its long-term progression.

Pain in persons with mild-moderate Parkinson's disease: a cross-sectional study of pain severity and associated factors

The aims of this study were to determine pain severity in persons with mild-moderate Parkinson's disease compared with healthy age- and sex-matched controls, and identify related factors, that is, demographic, disease severity, and functioning, of pain severity in the Parkinson's disease group. A cross-sectional study design was adopted to assess pain severity in 100 persons with Parkinson's disease and 47 healthy controls. Bodily pain was assessed using item 21 of the Short Form 36, whereas pain severity was determined using the entire Short Form 36 Bodily Pain subscale (score ranging from 0 to 100). Self-report questionnaires and clinical tests were completed to determine factors, that is, demographic and disease severity characteristics as well as physical functioning indicators, related to pain severity. Based on fulfillment of assumptions of data normality, both univariate and multivariate regression analysis were carried out. Pain severity (P < 0.001) was significantly higher in persons with Parkinson's disease than healthy controls. Among persons with Parkinson's disease, the multivariate predictor model, explaining 34% of the variance in pain severity scores, identified three independently associated factors. Poorer balance performance, a shorter disease duration, and poorer health-related quality of life were independently associated with pain severity. Pain severity is higher in those living with Parkinson's disease than controls, and severity appears to be associated with disease characteristics and overall health. Further research is required to assess pain origin in Parkinson's disease with the aim of developing targeted interventions.

Nonpharmacological Modulation of Chronic Inflammation in Parkinson's Disease: Role of Diet Interventions

Neuroinflammation is increasingly recognized as an important pathophysiological feature of neurodegenerative diseases such as Parkinson's disease (PD). Recent evidence suggests that neuroinflammation in PD might originate in the intestine and the bidirectional communication between the central and enteric nervous system, the so-called "gut-brain axis," has received growing attention due to its contribution to the pathogenesis of neurological disorders. Diet targets mediators of inflammation with various mechanisms and combined with dopaminergic treatment can exert various beneficial effects in PD. Food-based therapies may favorably modulate gut microbiota composition and enhance the intestinal epithelial integrity or decrease the proinflammatory response by direct effects on immune cells. Diets rich in pre- and probiotics, polyunsaturated fatty acids, phenols including flavonoids, and vitamins, such as the Mediterranean diet or a plant-based diet, may attenuate chronic inflammation and positively influence PD symptoms and even progression of the disease. Dietary strategies should be encouraged in the context of a healthy lifestyle with physical activity, which also has neuroimmune-modifying properties. Thus, diet adaptation appears to be an effective additive, nonpharmacological therapeutic strategy that can attenuate the chronic inflammation implicated in PD, potentially slow down degeneration, and thereby modify the course of the disease. PD patients should be highly encouraged to adopt corresponding lifestyle modifications, in order to improve not only PD symptoms, but also general quality of life. Future research should focus on planning larger clinical trials with dietary interventions in PD in order to obtain hard evidence for the hypothesized beneficial effects.

Exercise and Parkinson's disease

Parkinson's disease (PD) is one of the most common neurodegenerative diseases in the world. Unfortunately, most of the currently used clinical therapies against PD are symptomatic and there is still no remedy can stop disease progression. Collective evidence shows that various kinds of exercise may reduce the risk of PD and do have positive impacts on both motor and nonmotor symptoms of PD. Additionally, exercise can also ameliorate the side effects such as wearing-off and dyskinesia induced by anti-PD therapeutics. In parallel with its benefits in ameliorating clinical symptoms, exercise modulates a range of supporting systems for brain maintenance and plasticity including neurogenesis, synaptogenesis, enhanced metabolism and angiogenesis. Exercise provides all these broad benefits on PD through inhibiting oxidative stress, repairing mitochondrial damage, and promoting the production of growth factors. Moreover, exercise reduces risk of other geriatric diseases such as diabetes, hypertension and cardiovascular disease, which may also contribute to PD pathogenesis. In summary, exercise is increasingly considered to be a complementary strategy to PD medications. In this chapter, we summarize the recent research progress on the beneficial effects of exercise on PD, discuss the underlying mechanisms, and highlight the promising prospects of exercise for antiparkinsonian therapy.

Exercise-induced hypoalgesia is present in people with Parkinson's disease: Two observational cross-sectional studies

BACKGROUND

Exercise is prescribed for people with Parkinson's disease to address motor and non-motor impairments, including pain. Exercise-induced hypoalgesia (i.e., an immediate reduction in pain sensitivity following exercise) is reported in the general population; however, the immediate response of pain sensitivity to exercise in people with Parkinson's disease is unknown. The purpose of this study was to investigate if exercise-induced hypoalgesia is present following isometric and aerobic exercise in people with Parkinson's disease, and if so, if it varies with the dose of aerobic exercise.

METHODS

Thirty people with idiopathic Parkinson's disease and pain-free age-matched controls completed two observational studies evaluating the response to: (a) right arm isometric exercise; and (b) treadmill walking at low and moderate intensities. Pressure pain thresholds were measured over biceps brachii and quadriceps muscles immediately before and after exercise, with increased thresholds after exercise indicating exercise-induced hypoalgesia.

RESULTS

Pressure pain thresholds increased in the Parkinson's disease group at all tested sites following all exercise bouts (e.g., isometric exercise, right bicep 29%; aerobic exercise, quadriceps, moderate intensity 8.9%, low intensity 7.1% (p ≤ 0.008)), with no effect of aerobic exercise dose (p = 0.159). Similar results were found in the control group.

CONCLUSIONS

Overall, people with Parkinson's disease experienced an exercise-induced hypoalgesia response similar to that of the control group, the extent of which did not vary between mild and moderate doses of aerobic exercise. Further research is warranted to investigate potential longer term benefits from exercise in the management of pain in this population.

SIGNIFICANCE

Isometric and aerobic exercise reduces pain sensitivity in people with Parkinson's disease. As exercise is important for people with Parkinson's disease, these results provide assurance that people with Parkinson's disease and pain can exercise without an immediate increase in pain sensitivity. The reduction in pain sensitivity with both modes and with low and moderate intensities of aerobic exercise suggests that people with Parkinson's disease can safely choose the mode and intensity of exercise that best suits their needs.

Chronic pain and pain processing in Parkinson's disease

Pain is experienced by the vast majority of patients living with Parkinson's disease. It is most often of nociceptive origin, but may also be ascribed to neuropathic (radicular or central) or miscellaneous sources. The recently validated King's Parkinson's Disease Pain Scale is based on 7 domains including musculoskeletal pain, chronic body pain (central or visceral), fluctuation-related pain, nocturnal pain, oro-facial pain, pain with discolouration/oedema/swelling, and radicular pain. The basal ganglia integrate incoming nociceptive information and contribute to coordinated motor responses in pain avoidance and nocifensive behaviors. In Parkinson's disease, nigral and extra-nigral pathology, involving cortical areas, brainstem nuclei, and spinal cord, may contribute to abnormal central nociceptive processing in patients experiencing pain or not. The dopamine deficit lowers multimodal pain thresholds that are amenable to correction following levodopa dosing. Functional brain imaging with positron emission tomography following administration of H₂¹⁵O revealed abnormalities in the sensory discriminative processing of pain (insula/SII), as well as in the affective motivational processing of pain (anterior cingulate cortex, prefrontal cortex). Pain management is dependent on efforts invested in diagnostic accuracy to distinguish nociceptive from neuropathic pain. Treatment requires an integrated approach including strategies to lessen levodopa-related response fluctuations, in addition to other pharmacological and non-pharmacological options such as deep brain stimulation and rehabilitation.

Relationships between gait and emotion in Parkinson's disease: A narrative review

BACKGROUND

Disturbance of gait is a key feature of Parkinson's disease (PD) and has a negative impact on quality of life. Deficits in cognition and sensorimotor processing impair the ability of people with PD to walk quickly, efficiently and safely. Recent evidence suggests that emotional disturbances may also affect gait in PD.

RESEARCH QUESTION

We explored if there were relationships between walking ability, emotion and cognitive impairment in people with PD.

METHODS

The literature was firstly reviewed for unimpaired individuals. The recent experimental evidence for the influence of emotion on gait in people with PD was then explored. The contribution of affective disorders to continuous gait disorders was investigated, particularly for bradykinetic and hypokinetic gait. In addition, we investigated the influence of emotional processing on episodic gait disturbances, such as freezing of gait. Potential effects of pharmacological, surgical and physical therapy interventions were also considered.

RESULTS

Emerging evidence showed that emotional disturbances arising from affective disorders such as anxiety and depression, in addition to cognitive impairment, could contribute to gait disorders in some people with PD. An analysis of the literature indicated mixed evidence that improvements in affective disorders induced by physical therapy, pharmacological management or surgery improve locomotion in PD.

SIGNIFICANCE

When assessing and treating gait disorders in people with PD, it is important to take into the account non-motor symptoms such as anxiety, depression and cognitive impairment, in addition to the motor sequalae of this progressive neurological condition.

The Effect of Physical Activity in Parkinson's Disease: A Mini-Review

This article will discuss the effects of physical activity in patients with Parkinson's disease. Presently, the motor and non-motor symptoms are difficult to treat with the current treatment of Parkinson's; therefore, as an adjuvant to the current treatment physical activity, has been recommended. Physical activity has been known to improve many symptoms in patients with Parkinson's disease. Some of these symptoms include the physical capacities, physical and cognitive functional capacities. Physical activity also slows the disease process, decreases the pain associated with Parkinson`s disease, prolongs the independent mobility (gait, balance, strength) and improves sleep, mood, memory hence improving the overall quality of life. Furthermore, physical activity has the potential to improve the non-motor symptoms (depression, apathy, fatigue, constipation) and the secondary complications of immobility (cardiovascular, osteoporosis) in Parkinson's disease.

Parkinson disease and musculoskeletal pain: an 8-year population-based cohort study

The aim of this study was to evaluate the incidence and clinical features of musculoskeletal pain (MSP) in patients with Parkinson disease (PD) compared with a control group without the disease. The retrospective cohort study used a subset of the Taiwan National Health Insurance Research Database (NHIRD) comprising information on 1 million beneficiaries randomly sampled from the entire population of Taiwan. A total of 490 patients aged 50 and above with newly diagnosed Parkinson disease were identified during a period from 2000 to 2005. Among them, 199 developed MSP after PD. The control group consisted of 1960 participants without PD over the study period randomly selected by matching PD cases according to the date of PD incidence, age, and sex. The study groups were then followed to the end of 2007. Musculoskeletal pain was the end point. The incidence rate ratios of MSP were higher in the PD group than in the control group, representing an adjusted hazard ratio of 1.31 (95% confidence interval 1.09 to 1.58). PD was associated with a significantly elevated risk of MSP in all sex and age stratifications, with the highest hazard ratio noted for middle-aged male patients with PD, followed by older male patients with PD. This study showed that the PD may significantly increase the risk of developing MSP. The risk of developing MSP seems to be greatest for middle-aged male patients with PD. Clinicians should be more alert for MSP in patients with PD, and early intervention should be considered.

Neuropathic Corneal Pain: Approaches for Management

Neuropathic pain is caused by a primary lesion or dysfunction of the nervous system and can occur in the cornea. However, neuropathic corneal pain (NCP) is currently an ill-defined disease. Patients with NCP are extremely challenging to manage, and evidence-based clinical recommendations for the management of patients with NCP are scarce. The objectives of this review are to provide guidelines for diagnosis and treatment of patients with NCP and to summarize current evidence-based literature in this area. We performed a systematic literature search of all relevant publications between 1966 and 2017. Treatment recommendations are, in part, based on methodologically sound randomized controlled trials (RCTs), demonstrating superiority to placebo or relevant control treatments, and on the consistency of evidence, degree of efficacy, and safety. In addition, the recommendations include our own extensive experience in the management of these patients over the past decade. A comprehensive algorithm, based on clinical evaluation and complementary tests, is presented for diagnosis and subcategorization of patients with NCP. Recommended first-line topical treatments include neuroregenerative and anti-inflammatory agents, and first-line systemic pharmacotherapy includes tricyclic antidepressants and an anticonvulsant. Second-line oral treatments recommended include an opioid-antagonist and opiate analgesics. Complementary and alternative treatments, such as cardiovascular exercise, acupuncture, omega-3 fatty acid supplementation, and gluten-free diet, may have additional benefits, as do potential noninvasive and invasive procedures in recalcitrant cases. Medication selection should be tailored on an individual basis, considering side effects, comorbidities, and levels of peripheral and centralized pain. Nevertheless, there is an urgent need for long-term studies and RCTs assessing the efficacy of treatments for NCP.

Physiotherapy for Parkinson's Disease in Sweden: Provision, Expertise, and Multi-professional Collaborations

Background

Evidence for the positive effects of physiotherapy for persons with Parkinson's disease (PwPD) is rapidly increasing. However, little is known about the provision of physiotherapy for PwPD in everyday practice. The objective of this study was to gain insight into the nature of physiotherapeutic care for PwPD in hospitals, primary care units, and community services in Sweden.

Methods

A web-based survey was sent out to 2956 members of the Swedish Association of Physiotherapists, including questions about treatment, measurement tools, multi-professional collaborations, adherence to physiotherapy guidelines, professional expertise, and needs for gaining expertise regarding PwPD.

Results

Of the 1189 physiotherapists who completed the survey, 705 were treating 1 or more PwPD per month in hospitals (21%), in primary care units (37%), and in the community (42%). Physiotherapy frequently targeted a wide range of musculoskeletal and mobility impairments; however, freezing of gait and pain were less frequently treated. Measurement tools recommended for PwPD were infrequently used, and there was a preference for single-item questions/tools compared with multi-item instruments. Collaboration with other health care professionals for the rehabilitation of PwPD was rare and was more evident in hospitals than in primary care units and the community. Adherence to physiotherapy guidelines was poor, and most respondents reported that they treated too few PwPD to retain their expertise and they perceived a need to increase their knowledge and skills about physiotherapy for PwPD.

Conclusion

The current findings emphasize the need to strengthen expertise regarding the assessment and treatment of PwPD among physiotherapists in Sweden and to apply strategies endorsing multi-professional collaboration for PD rehabilitation.

Understanding and Treating Pain Syndromes in Parkinson's Disease

Pain affects many people with Parkinson's disease (PD) and diminishes their quality of life. Different types of pain have been described, but their related pathophysiological mechanisms remain unclear. The aim of this chapter is to provide movement disorders specialists an update about the pathophysiology of pain and a practical guide for the management of pain syndromes in clinical practice. This chapter reviews current knowledge on the pathophysiological mechanisms of sensory changes and pain in PD, as well as assessment and treatment procedures to manage these symptoms. In summary, changes in peripheral and central pain processing have been demonstrated in PD patients. A decrease in pain threshold and tolerance to several stimuli, a reduced nociceptive withdrawal reflex, a reduced pain threshold, and abnormal pain-induced activation in cortical pain-related areas have been reported. There is no direct association between improvement of motor symptoms and sensory/pain changes, suggesting that motor and nonmotor symptoms do not inevitably share the same mechanisms. Special care in pain assessment in PD is warranted by the specific pathophysiological aspects and the complexity of motor and nonmotor symptoms associated with pain symptoms. Rehabilitation may represent a valid option to manage pain syndromes in PD. However, further research in this field is needed. An integrated approach to pain involving a multidisciplinary team of medical specialists and rehabilitation experts should allow a comprehensive approach to pain in PD.

Evaluation of the safety and immunomodulatory effects of sargramostim in a randomized, double-blind phase 1 clinical Parkinson's disease trial

A potential therapeutic role for immune transformation in Parkinson’s disease evolves from more than a decade of animal investigations demonstrating regulatory T cell (Treg) nigrostriatal neuroprotection. To bridge these results to human disease, we conducted a randomized, placebo-controlled double-blind phase 1 trial with a well-studied immune modulator, sargramostim (granulocyte-macrophage colony-stimulating factor). We enrolled 17 age-matched non-Parkinsonian subjects as non-treated controls and 20 Parkinson’s disease patients. Both Parkinson’s disease patients and controls were monitored for 2 months for baseline profiling. Parkinson’s disease patients were then randomized into two equal groups to self-administer placebo (saline) or sargramostim subcutaneously at 6 μg/kg/day for 56 days. Adverse events for the sargramostim and placebo groups were 100% (10/10) and 80% (8/10), respectively. These included injection site reactions, increased total white cell counts, and upper extremity bone pain. One urticarial and one vasculitis reaction were found to be drug and benzyl alcohol related, respectively. An additional patient with a history of cerebrovascular disease suffered a stroke on study. Unified Parkinson’s disease rating scale, Part III scores in the sargramostim group showed modest improvement after 6 and 8 weeks of treatment when compared with placebo. This paralleled improved magnetoencephalography-recorded cortical motor activities and Treg numbers and function compared with pretreated Parkinson’s disease patients and non-Parkinsonian controls. Peripheral Treg transformation was linked to serum tryptophan metabolites, including L-kynurenine, quinolinic acid, and serotonin. These data offer a potential paradigm shift in modulating immune responses for potential therapeutic gain for Parkinson’s disease. Confirmation of these early study results requires larger numbers of enrolled patients and further clinical investigation.

The immune system modulating drug sargramostim shows promising results in a small clinical trial with Parkinson’s disease (PD) patients. Previous studies have shown that sargramostim increases the number of regulatory T cells, attenuates immune responses, and confers neuroprotection in animal models of neurodegenerative disease. To determine whether these findings translate to humans, Howard E. Gendelman at the University of Nebraska Medical Center, USA, and colleagues examined the effects of sargramostim in 20 patients with PD. Despite the high number of mild to moderate reported adverse events, the drug was generally well tolerated and led to an increase in regulatory T cell number and activity. Moreover, preliminary assessments after 6 and 8 weeks of treatment suggested an overall improvement in the motor skills of patients that received the drug compared with those that received a placebo.

Neuroprotective effects of endurance exercise against neuroinflammation in MPTP-induced Parkinson's disease mice

Parkinson's disease (PD) is one of the main degenerative neurological disorders accompanying death of dopaminergic neurons prevalent in aged population. Endurance exercise (EE) has been suggested to confer neurogenesis and mitigate the degree of seriousness of PD. However, underlying molecular mechanisms responsible for exercise-mediated neuroprotection against PD remain largely unknown. Given the relevant interplay between elevated α-synuclein and neuroinflammation in a poor prognosis and vicious progression of PD and anti-inflammatory effects of EE, we hypothesized that EE would reverse motor dysfunction and cell death caused by PD. To this end, we chose a pharmacological model of PD (e.g., chronic injection of neurotoxin MPTP). Young adult male mice (7 weeks old) were randomly divided into three groups: sedentary control (C, n=10), MPTP (M, n=10), and MPTP + endurance exercise (ME, n=10). Our data showed that EE restored motor function impaired by MPTP in parallel with reduced cell death. Strikingly, EE exhibited a significant reduction in α-synuclein protein along with diminished pro-inflammatory cytokines (i.e., TNF-α and IL-1β). Supporting this, EE prevented activation of Toll like receptor 2 (TLR2) downstream signaling cascades such as MyD88, TRAF6 and TAK-1 incurred by in MPTP administration in the striatum. Moreover, EE reestablished tyrosine hydroxylase at levels similar to C group. Taken together, our data suggest that an EE-mediated neuroprotective mechanism against PD underlies anti-neuroinflammation conferred by reduced levels of α-synuclein. Our data provides an important insight into developing a non-pharmacological countermeasure against neuronal degeneration caused by PD.

Understanding Neuropathic Corneal Pain--Gaps and Current Therapeutic Approaches

The richly innervated corneal tissue is one of the most powerful pain generators in the body. Corneal neuropathic pain results from dysfunctional nerves causing perceptions such as burning, stinging, eye-ache, and pain. Various inflammatory diseases, neurological diseases, and surgical interventions can be the underlying cause of corneal neuropathic pain. Recent efforts have been made by the scientific community to elucidate the pathophysiology and neurobiology of pain resulting from initially protective physiological reflexes, to a more persistent chronic state. The goal of this clinical review is to briefly summarize the pathophysiology of neuropathic corneal pain, describe how to systematically approach the diagnosis of these patients, and finally summarizing our experience with current therapeutic approaches for the treatment of corneal neuropathic pain.

The Association Between Parkinson's Disease Motor Impairments and Pain

OBJECTIVE

This study aimed to: 1) examine the severity and frequency of pain and the extent to which pain interferes with work and 2) explore the contributions of motor impairments to pain in people with Parkinson's disease (PD).

METHOD

Pain severity, frequency and the impact of pain on work were determined using subscores from the SF-36^TM, Parkinson's Disease Questionnaire and SF-12v2^TM, respectively, in 231 people with Parkinson's disease. Motor impairments were measured using the Unified Parkinson's Disease Rating Scale. Freezing of gait was determined as its presence or absence in the last month. Associations between impairments and pain were examined using logistic regression.

RESULTS

Pain was reported by 187 (81%) participants, with 91 (39%) reporting pain of moderate severity or worse. Pain interfered with work to some extent in 158 (68%) participants. After adjusting for age and gender, increased rigidity was associated with higher pain frequency and more pain that interfered with work (for both models, Odds Ratio = 1.14, 95% confidence interval 1.0-1.3). Tremor was not associated with any measures of pain and motor impairments were not associated with pain severity.

CONCLUSIONS

Most people with PD experience pain at least monthly and pain interferes with daily activities. PD impairments are associated with more frequent pain and pain that interferes with work, with rigidity having the strongest association. Development of Parkinson's disease-specific pain assessments and further investigation into the association between PD impairments and pain is warranted.

Predictors of Adherence to a Falls Prevention Exercise Program for People with Parkinson's Disease

BACKGROUND

Long-term benefits of exercise for people with Parkinson's disease (PD) require regular and sustained participation. This study aimed to investigate predictors of adherence to a minimally supervised exercise program designed to reduce falls in people with PD.

METHOD

People with idiopathic PD who participated in the exercise arm of a randomized, controlled trial were included. Exercises were prescribed three times per week for 6 months. Adherence was defined as the percentage of prescribed sessions participants reported as having undertaken. Potential predictors of adherence included baseline measures of demographic variables, disease severity and duration, falls and fear of falling, pain, self-reported health and quality of life, cognition, physical activity levels, freezing of gait, functional mobility and balance, and knee extensor strength.

RESULTS

The 108 participants included undertook a mean of 72% (standard deviation: 38%) of prescribed sessions. Participants had higher levels of adherence if they had shorter disease duration, less bodily pain, and better self-reported health and quality of life. A multivariate model (including disease duration, severity of bodily pain, self-reported physical well-being, the Frontal Assessment Battery, the Short Physical Performance Battery, and maximum walking time) explained 9% of the variance in exercise adherence, with shorter disease duration and less pain the strongest predictors (both predictors standardized β = -0.2; P = 0.04).

CONCLUSION

Disease duration and pain are likely to negatively influence exercise participation in people with PD. Given that most of the variance in adherence is unexplained, further work is required to determine other predictors of adherence to long-term exercise programs.

Treatment of Neuropathic Pain

OPINION STATEMENT

Neuropathic pain is notoriously variable in its severity and impact on patients, as well as in its response to treatment. Certain therapies for neuropathic pain have better evidence for their use; however, it is apparent that although some therapies provide relief for only a minority of patients, the relief may be significant. Without a trial of therapy, there is no way to know if that relief is achievable. Our treatment experiences have shown that occasionally unexpected benefit is obtained through a thorough investigation of all options, even in the setting of failure of those with the most compelling evidence or indication. Chronic neuropathic pain is generally best treated with regularly dosed medications, balancing efficacy and tolerability. Evidence supports first-line trials of anticonvulsants, tricyclic antidepressants, and serotonin-norepinephrine reuptake inhibitors, alone or in certain combinations. While opioid medications, particularly methadone, can be effective in treating neuropathic pain, they are best used only in refractory cases and by experienced clinicians, due to concerns for both short- and long-term safety. Some therapies have a long history of successful use for certain syndromes (e.g., carbamazepine for trigeminal neuralgia pain), but these should not be considered to the exclusion of other more recent, less-supported therapies (e.g., botulinum toxin A for the same), particularly in refractory cases. We find the principles of palliative care highly applicable in the treatment of chronic neuropathic pain, including managing expectations, mutually agreed-upon meaningful outcomes, and a carefully cultivated therapeutic relationship.