The Epidemiology of Nonmotor Symptoms in Parkinson's Disease (Cohort and Other Studies)

Evaluation of non-motor symptoms in cervical dystonia, hemifacial spasm, and blepharospasm patients and their correlation with motor symptoms

BACKGROUND

Awareness of non-motor symptoms has been increasing in recent years, but there are still few studies on this topic.

OBJECTIVE

Our aim was to evaluate various non-motor symptoms, especially psychiatric disorders, cognitive status, and sleep, in cervical dystonia (CD), hemifacial spasm (HFS), and blepharospasm (BPS) patients and to investigate whether these symptoms are related to the severity of motor symptoms.

METHODS

This was a single-center cross-sectional, observational, case-control study. Motor severity scales were used to determine disease severity. We evaluated non-motor symptoms with commonly used scales. A total of 73 patients and 73 control groups participated.

RESULTS

In CD patients, the MoCA total score, 'language', 'abstraction', and 'orientation' scores were statistically significantly lower; PSQI, ESS, and NMSQ scores were statistically significantly higher than controls. In the BPS group, the MoCA total score and the 'language' score were significantly lower, and the NMSQ score was statistically significantly higher than the controls. In the HFS group, MoCA total score, 'executive functions', 'language', and 'abstraction' scores were statistically significantly lower; PSQI scores are statistically significantly higher than controls. There was a positive correlation between the severity score and the PSQI score in the CD group and between the severity score and the NMSQ score in the BPS group. All three groups had significant cognitive impairments.

CONCLUSIONS

In CD, BPS, and HFS, non-motor symptoms are apparent with undeniable frequency in addition to common motor symptoms. Importantly, these NMS may cause significant deterioration in the quality of life of the patients.

Enteric nervous system as a target and source of SARS-CoV-2 and other viral infections

Coronavirus disease 2019 (COVID-19) has been demonstrated to affect several systems of the human body, including the gastrointestinal and nervous systems. The enteric nervous system (ENS) is a division of the autonomic nervous system that extends throughout the gut, regulates gastrointestinal function, and is therefore involved in most gut dysfunctions, including those resulting from many viral infections. Growing evidence highlights enteric neural cells and microbiota as important players in gut inflammation and dysfunction. Furthermore, the ENS and gastrointestinal immune system work together establishing relevant neuroimmune interactions during both health and disease. In recent years, gut-driven processes have also been implicated as players in systemic inflammation and in the initiation and propagation of several central nervous system pathologies, which seem to be hallmarks of COVID-19. In this review, we aim to describe evidence of the gastrointestinal and ENS infection with a focus on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We discuss here viral-induced mechanisms, neuroplasticity, and neuroinflammation to call attention to the enteric neuroglial network as a nervous system with a sensitive and crucial position to be not only a target of the new coronavirus but also a way in and trigger of COVID-19-related symptoms.

Natural Compounds as Medical Strategies in the Prevention and Treatment of Psychiatric Disorders Seen in Neurological Diseases

Psychiatric disorders are frequently encountered in many neurological disorders, such as Alzheimer’s and Parkinson diseases along with epilepsy, migraine, essential tremors, and stroke. The most common comorbid diagnoses in neurological diseases are depression and anxiety disorders along with cognitive impairment. Whether the underlying reason is due to common neurochemical mechanisms or loss of previous functioning level, comorbidities are often overlooked. Various treatment options are available, such as pharmacological treatments, cognitive-behavioral therapy, somatic interventions, or electroconvulsive therapy. However oral antidepressant therapy may have some disadvantages, such as interaction with other medications, low tolerability due to side effects, and low efficiency. Natural compounds of plant origin are extensively researched to find a better and safer alternative treatment. Experimental studies have shown that phytochemicals such as alkaloids, terpenes, flavonoids, phenolic acids as well as lipids have significant potential in in vitro and in vivo models of psychiatric disorders. In this review, various efficacy of natural products in in vitro and in vivo studies on neuroprotective and their roles in psychiatric disorders are examined and their neuro-therapeutic potentials are shed light.

Motor Cortex Stimulation Reversed Hypernociception, Increased Serotonin in Raphe Neurons, and Caused Inhibition of Spinal Astrocytes in a Parkinson's Disease Rat Model

Persistent pain is a prevalent symptom of Parkinson’s disease (PD), which is related to the loss of monoamines and neuroinflammation. Motor cortex stimulation (MCS) inhibits persistent pain by activating the descending analgesic pathways; however, its effectiveness in the control of PD-induced pain remains unclear. Here, we evaluated the analgesic efficacy of MCS together with serotonergic and spinal glial modulation in an experimental PD (ePD) rat model. Wistar rats with unilateral striatal 6-OHDA and MCS were assessed for behavioral immobility and nociceptive responses. The immunoreactivity of dopamine in the substantia nigra and serotonin in the nucleus raphe magnus (NRM) and the neuronal, astrocytic, and microglial activation in the dorsal horn of the spinal cord were evaluated. MCS, without interfering with dopamine loss, reversed ePD-induced immobility and hypernociception. This response was accompanied by an exacerbated increase in serotonin in the NRM and a decrease in neuronal and astrocytic hyperactivation in the spinal cord, without inhibiting ePD-induced microglial hypertrophy and hyperplasia. Taken together, MCS induces analgesia in the ePD model, while restores the descending serotonergic pathway with consequent inhibition of spinal neurons and astrocytes, showing the role of MCS in PD-induced pain control.

Is Dysphagia in Older Patients with Parkinson's Disease Associated With Sarcopenia ?

BACKGROUND

Parkinson's Disease (PD) and sarcopenia share a number of common pathways, and they can potentially affect each other.

OBJECTIVE

We aimed to investigate the relationship between dysphagia and sarcopenia in elderly patients with PD compared to healthy controls.

METHODS

This case-control study was conducted on 54 elderly PD patients and age-, sex- and body mass index-matched 54 healthy elder persons. Demographic and disease characteristics such as disease duration, stage of disease and Unified Parkinson's disease rating scale were recorded. All subjects were assessed by 10- item Eating Assessment Tool, Gugging Swallowing Screen tests and flexible fiberoptic endoscopic evaluation of swallowing (FEES) as well as Mini nutritional test short form. Also, A simplified screening tool for assessing sarcopenia (SARC-F), five times sit-to-stand and gait speed tests as well as lumbar magnetic resonance imaging (MRI) cross-sectional area of psoas and paraspinal muscles were used for evaluation of sarcopenia. Patients were divided as «with normal swallowing» or «with dysphagia» according to the FEES results. Three groups were compared among themselves in terms of evaluation methods.

RESULTS

Sarcopenia evaluation parameters were significantly higher in patient groups compared to the control group. Moreover, muscle measurements evaluated by MRI in patients with dysphagia are lower than both patients with normal swallowing and control group (p value between 0.001 and 0.011).

CONCLUSIONS

Patients with PD have lower muscle mass compared to healthy controls, and the situation is more pronounced in dysphagic PD patients.

Prevalence of Non-Motor Symptoms and Non-Motor Fluctuations in Parkinson's Disease Using the MDS-NMS

Background

Non-motor symptoms (NMS) are frequent in Parkinson's disease (PD).

Objectives

To estimate the prevalence of NMS and of non-motor fluctuations (NMF) using the Movement Disorders Society-Non-Motor Rating Scale (MDS-NMS) and other scales assessing NMS, and their relationship with sex and PD severity.

Methods

Cross-sectional study with a sample of 402 PD patients. The Hoehn and Yahr staging system (HY), Clinical Impression of Severity Index for PD (CISI-PD), MDS-NMS (including NMF- subscale), Non-Motor Symptoms scale (NMSS), and MDS-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) were applied. A NMS was considered present when scored ≥1. Differences in scores by sex and HY, CISI-PD, and MDS-UPDRS severity levels were calculated using Fisher's exact and chi-squared tests.

Results

Using the MDS-NMS, NMS were present in 99.7% of patients and the mean number of NMS was 16.13 (SD: 9.36). The most prevalent NMS was muscle, joint or back pain (67.4% of the sample) and the least prevalent was dopamine dysregulation syndrome (2.2%). Feeling sad or depressed was significantly more prevalent in women. Using the MDS-NMS revealed more NMS than the other scales assessing NMS. NMF were present in 41% of the sample, with fatigue being the most prevalent symptom (68.5% patients with NMF), and no differences by sex. Patients with greater PD severity had higher prevalence of NMS than patients with lower severity.

Conclusions

Almost all patients with PD experience NMS, and many experience NMF. Prevalence rates for NMS using the MDS-NMS are higher than on other scales used and increase with higher disease severity.

Increased plasma orexin-A concentrations are associated with the non-motor symptoms in Parkinson's disease patients

BACKGROUND

Orexin, a neuropeptide primarily secreted by neurons in the lateral hypothalamus, has been implicated in Parkinson's disease (PD). Studies on the relationship between plasma orexin-A levels and PD are rare.

OBJECTIVES

This study aimed to assess levels of plasma orexin-A in the progression of PD and to evaluate the correlation between orexin-A levels and non-motor symptoms.

METHODS

Enzyme-linked immunosorbent assay was used to determine plasma orexin-A levels in 117 healthy controls and 121 PD patients, including those with early (n = 68), medium (n = 40) and advanced (n = 13) stages of the disease. Evaluation of motor symptoms and non-motor symptoms in PD patients, such as sleep disorders, cognitive dysfunction, neuropsychiatric symptoms, autonomic nervous dysfunction, hyposmia and PD-related pain, were assessed by the associated scales.

RESULTS

Plasma orexin-A levels were significantly higher in PD patients compared to healthy controls. Orexin-A levels were elevated in early-stage and medium-stage PD compared to healthy controls, but were decreased in advanced-stage PD. Orexin-A levels were negatively correlated with the Unified Parkinson's Disease Rating Scale Part III scores, disease duration, and dopamine receptor agonist doses, and were positively correlated with the Pittsburgh Sleep Quality Index, REM-sleep Behavior Disorder Questionnaire, 14-item Hamilton Anxiety Scale, Mini-Mental State Examination, and Non-motor Symptom Scale items 22-24 scores.

CONCLUSIONS

We found for the first time that plasma orexin-A levels were increased in early-stage and medium-stage PD and were decreased in advanced-stage PD. Furthermore, orexin-A levels were correlated with the non-motor symptoms of insomnia, REM-sleep behavior disorder, anxiety, cognitive dysfunction, and renal dysfunction.

Effects of Subthalamic Deep Brain Stimulation With Different Frequencies in a Parkinsonian Rat Model

OBJECTIVE

Subthalamic deep brain stimulation (STN-DBS) could be an effective alternative treatment for patients with Parkinson's disease (PD). However, the mechanisms of deep brain stimulation (DBS) at different frequencies are still unclear. In this study, diffusion tensor imaging (DTI) was used to detect parameter changes in different regions of rat brains after DBS, and rat exercise capacity and brain tissue immunohistochemistry were evaluated.

MATERIALS AND METHODS

The 6-hydroxydopamine-induced hemi-parkinsonian rat models were made and divided into four groups: a control group, sham group, low-frequency group, and high-frequency group. Low-frequency (30 Hz) and high-frequency (130 Hz) DBS were given to the STN in rats. First, an open-field experiment was used to evaluate changes in exercise performance. Then, the DTI was used to measure parameter changes in the substantia nigra (SN). Finally, immunohistochemistry was used to analyze the expression of tyrosine hydroxylase (TH), NeuN, and α-synuclein (α-syn) in the SN in the rats.

RESULTS

There were significant differences in movement distance changes between the high-frequency stimulation (HFS) group and low-frequency stimulation (LFS) group, the HFS group and Ctrl group, and the Sham group and Ctrl group (all p < 0.05) after one week of stimulation. In the HFS group, the fractional anisotropy value of the SN was significantly higher than that of the other groups (p < 0.05), and the apparent diffusion coefficient and radial diffusion coefficient values were significantly lower than those of the other groups (p < 0.01). Immunohistochemical analysis showed that the integral optical density values of SN TH staining (p < 0.01) and NeuN staining (p < 0.05) in the HFS group were both significantly higher than those in the other groups.

CONCLUSION

STN-HFS (130 Hz) and sham operation for one week can significantly improve the exercise performance of PD rats. The exercise performance of PD rats in LFS group (30 Hz) is worse compared with HFS group (130 Hz). HFS plays a role in neuroprotection and improvement of exercise performance of PD rats. Moreover, DTI can be used as an effective technique to assess the therapeutic effects and severity of PD.

Widespread Pressure Pain Hyperalgesia Is Not Related to Pain in Patients with Parkinson's Disease

OBJECTIVE

Pain is one of the most frequent nonmotor impairments in Parkinson's disease (PD) and is hypothesized to be associated with altered nociceptive pain processing. Our aims were to investigate differences in widespread pressure pain sensitivity between PD patients with and without pain and healthy controls and to assess the relationship of health-related quality of life and sleep quality with pressure pain sensitivity.

METHODS

Nineteen PD patients with pain (12 men, age = 68 ± 9 years), 19 PD patients without pain (11 men, age = 69 ± 8 years), and 19 matched controls participated. Pressure pain thresholds (PPTs) were assessed bilaterally over the cervical spine, the second metacarpal, and the tibialis anterior by an assessor blinded to the subject's condition. Patients were assessed in a dopamine-medicated (ON) state. Pain intensity (numerical pain rating scale, 0-10), health-related quality of life (39-item Parkinson's Disease Questionnaire), and sleep quality (Pittsburgh Sleep Quality Index) were also assessed.

RESULTS

No significant differences existed between PD patients, with or without pain, and healthy controls on PPTs over the cervical spine, the second metacarpal, or the tibialis anterior muscle (all P > 0.3). PPTs were lower in females than in males in all groups (P < 0.01). In PD patients with pain, worse quality of sleep was associated with higher widespread pressure pain sensitivity (-0.607 < r < -0.535, P < 0.05). No other significant association was observed.

CONCLUSIONS

This study revealed no differences in widespread pressure hyperalgesia between PD patients with or without pain (ON state) and controls. Although dopamine may modulate pain responses, other mechanisms seems to also be implicated in altered nociceptive pain processing in patients with PD.

"New methods of assessing autonomic disorders in Parkinson disease patients: skin-galvanic reaction"

The aim of this study was to assess quantitatively sweating in PD patients. In the study, the galvanic-skin reaction (GSR) was used. The GSR was tested using eSense Skin Reaction device. The results show that sweating in patients with Parkinson's disease on drugs (PD ON) and control patients is similar, while patients with PD without levodopa (PD OFF) have higher perspiration.

Comparison of Mono-dopaminergic and Multi-target Pharmacotherapies in Primary Parkinson Syndrome and Assessment Tools to Evaluate Motor and Non-motor Symptoms

Background:

Primary Parkinson syndrome is mostly treated by dopaminergic drugs, while the progression of the disease is not altered. Some non-dopaminergic are available, which are administered only after the Parkinsonian symptoms get worse.

Objective:

The objective of this review is to give basic results in order to compare a dopaminergic and non-dopaminergic pharmacotherapy in Parkinson’s disease and to control whether the add-on pharmacotherapy with non-dopaminergic drugs can inhibit the progression of the disease.

Methods:

In primary Parkinson syndrome, the altered activity of classical neurotransmitters and neuropeptides in the extrapyramidal system is summarized and up-dated. Anatomical studies on neural networks in the basal ganglia are mentioned. The direct, motor facilitatory pathway (D1 dopaminergic neurons) from the substantia nigra to the thalamus, via the internal globus pallidus, and the indirect, motor inhibitory pathway via D2 dopaminergic neurons have been considered. These established anatomical pathways have been brought in line with the neural interactions derived from neurotransmitter balances or imbalances. Besides, preclinical and clinical studies of effective non-dopaminergic anti-Parkinsonian drugs are reviewed.

Results:

It can be hypothesized that glutamatergic neurons enhance dopamine deficiency in the substantia nigra and putamen through an increased presynaptic inhibition mediated by NMDA receptors. In the putamen, 5-HT2A serotonergic neurons counteract D2 dopaminergic neurons and A2A adenosine neurons antagonize D2 dopaminergic neurons by activating glutamatergic neurons, which presynaptically inhibit via subtype 5 of metabotropic glutamatergic receptors, D2 dopaminergic neurons. In the extrapyramidal system, an up-dated neural network, which harmonizes established anatomical pathways with derived neural interactions, is presented. In Parkinson’s disease, a question should be answered, whether a combination of dopaminergic and non-dopaminergic drugs can promote an increased motor and non-motor functioning.

Conclusion:

A mono-target pharmacotherapy (using only dopaminergic drugs) and a multi-target pharmacotherapy (i.e. by combining dopaminergic and non-dopaminergic drugs) are compared. The alternate administration of dopaminergic and non-dopaminergic anti-Parkinsonian drugs, administered at different times during the day, must be tested in order to inhibit the progression of the disease. Assessment tools can be used to evaluate motor and cognitive functions. Moreover, imaging examination techniques can be also applied to control the course of the disease.

Non-motor Parkinson disease: new concepts and personalised management

Most patients with Parkinson disease (PD) have non-motor symptoms (NMS), and on average these can range from four to 19 different symptoms. NMS dominate the prodromal phase of PD and some may serve as clinical biomarkers of PD. NMS can be dopaminergic, non-dopaminergic, of genetic origin or drug induced. Clinical assessment of NMS should include the NMS Questionnaire (completed by patients) for screening, as recommended by the International Parkinson and Movement Disorders Society and other international societies. The total number of NMS in a patient with PD constitutes the NMS burden, which can be graded using validated cut-off scores on the NMS Questionnaire and Scale and can be used as an outcome measure in clinical trials. Despite NMS burden having a major effect on the quality of life of patients and carers, a large European study showed that NMS are often ignored in the clinic. The syndromic nature of PD is underpinned by non-motor subtypes which are likely to be related to specific dysfunction of cholinergic, noradrenergic, serotonergic pathways in the brain, not just the dopaminergic pathways. NMS can be treated by dopaminergic and non-dopaminergic strategies, but further robust studies supported by evidence from animal models are required. The future of modern treatment of PD needs to be supported by the delivery of personalised medicine.

Descriptive analysis of the French NS-Park registry: Towards a nation-wide Parkinson's disease cohort?

INTRODUCTION

Parkinson's disease (PD) is the second most common neurodegenerative disorder after Alzheimer's. The French clinical research network for PD (NS-Park) has created a national patient registry to i)report medical activity of Parkinson Expert Centers (PECs) to the Ministry of Health, ii)facilitate PD patients pre-screening for clinical trials, iii) provide a source for pharmaco-epidemiology studies.

OBJECTIVE

Assess the French Parkinsonian population at a nation-wide level and discover new clinical characteristics.

METHODS

In this feasibility study, PECs prospectively collected clinical data in a standardized manner. The population main clinical characteristics are described, focusing on motor and non-motor symptoms and treatments, assessing its representativeness. By using an unbiased clustering with multiple correspondence analysis (MCA), we also investigate potential relationships between multiple variables like symptoms and treatments, as clues for future studies.

RESULTS

Between 2012 and 2016, among 11,157 included parkinsonian syndromes, 9454 (85%) had PD. MCA identified various profiles depending on disease duration. Occurrences of motor complications, axial signs, cognitive disorders and Levodopa use increase over time. Neurovegetative symptoms, psychiatric disorders, sleep disturbances and impulse control disorders (ICDs) seem stable over time. As expected, ICDs were associated to dopaminergic agonist use but other associations, such as ICDs and sleep disturbances for instance, or anxiety and depression, were found.

CONCLUSIONS

Our results report one of the biggest PD registries ever reported and demonstrate the feasibility of implementing a nation-wide registry of PD patients in France, a potent tool for future longitudinal studies and clinical trials' population selection, and for pharmaco-epidemiology and cost-effectiveness studies.

Exploring hyperhidrosis and related thermoregulatory symptoms as a possible clinical identifier for the dysautonomic subtype of Parkinson's disease

Objective

To identify associated (non-)motor profiles of Parkinson’s disease (PD) patients with hyperhidrosis as a dominant problem.

Methods

This is a cross-sectional, exploratory, analysis of participants enrolled in the Non-motor Longitudinal International Study (NILS; UKCRN No: 10084) at the Parkinson’s Centre at King’s College Hospital (London, UK). Hyperhidrosis scores (yes/no) on question 28 of the Non-Motor Symptom Questionnaire were used to classify patients with normal sweat function (n = 172) and excessive sweating (n = 56) (Analysis 1; n = 228). NMS scale (NMSS) question 30 scores were used to stratify participants based on hyperhidrosis severity (Analysis 2; n = 352) using an arbitrary severity grading: absent score 0 (n = 267), mild 1–4 (n = 49), moderate 5–8 (n = 17), and severe 9–12 (n = 19). NMS burden, as well as PD sleep scale (PDSS) scores were then analysed along with other correlates.

Results

No differences were observed in baseline demographics between groups in either analysis. Patients with hyperhidrosis exhibited significantly higher total NMSS burden compared to those without (p < 0.001). Secondary analyses revealed higher dyskinesia scores, worse quality of life and PDSS scores, and higher anxiety and depression levels in hyperhidrosis patients (p < 0.001). Tertiary analyses revealed higher NMSS item scores for fatigue, sleep initiation, restless legs, urinary urgency, and unexplained pain (p < 0.001).

Conclusions

Chronic hyperhidrosis appears to be associated with a dysautonomia dominant subtype in PD patients, which is also associated with sleep disorders and a higher rate of dyskinesia (fluctuation-related hyperhidrosis). These data should prompt the concept of hyperhidrosis being used as a simple clinical screening tool to identify PD patients with autonomic symptoms.

Quality of life in functional movement disorders is as altered as in organic movement disorders

OBJECTIVE

Patients with functional movement disorders (FMD) often report a disability and psychiatric comorbidities. However, few studies have compared these aspects in FMD and in organic movement disorders (OMD). The objectives were to compare QoL and psychiatric comorbidities of FMD and OMD patients.

METHODS

Twenty-one and 30 FMD patients were compared to 21 and 30 sex- and age-matched dystonia and Parkinson patients respectively. QoL was assessed using the Parkinson's Disease Summary Index (PDSI). Psychiatric comorbidities were screened with the Mini International Neuropsychiatric Interview, the Hospital Anxiety and Depression Scale and the Composite International Diagnostic Interview questionnaire.

RESULTS

QoL was more altered in FMD than in dystonia on PDSI (42.1 vs 25.1; p = .003). No significant difference was observed in QoL in FMD and Parkinson's disease on PDSI (38.3 vs 32.2; p = .61). Moreover, FMD patients were more often unemployed because of their condition than dystonia (61.9% vs 14.3%; p = .01) and Parkinson patients (53.3% vs 13.3%; p = .005). The occurrence of anxiety (p = .58 and > 0.99), depression (p = .77 and 0.77), and traumatic events (p = .58 and 0.75) was not different between groups. FMD patients reported more often sexual abuse than dystonia (28,6% vs 4.8%; p = .13) and Parkinson patients (23.3% vs 0.0%; p = .02).

CONCLUSION

FMD patients presented a significant alteration of QoL and no increased psychiatric comorbidities compared to OMD patients. These results highlight the impact of FMD and suggest that neurologists should be as involved in the management of FMD as they are in OMD.

Apomorphine for Parkinson's Disease: Efficacy and Safety of Current and New Formulations

Satisfactory management of Parkinson's disease is a challenge that requires a tailored approach for each individual. In the advanced phase of the disease, patients may experience motor complications despite optimized pharmacological therapy. Apomorphine, a short-acting D₁- and D₂-like receptor agonist, is the only drug proven to have an efficacy equal to that of levodopa, albeit with a shorter time to onset and effect duration. Clinical trials have shown that intermittent apomorphine injections provide rapid and effective relief from unpredictable "off" periods. Continuous apomorphine infusion reduced around 50% of the daily "off" time in several studies. Dopaminergic side effects such as nausea, somnolence and hypotonia, as well as administration site reactions, are often mild or treatable, but somnolence and skin reactions in particular can sometimes be reasons for premature discontinuation. We provide an overview of the pharmacological mechanism of action of the drug in light of its effects on Parkinson's disease symptoms. We then summarize the evidence regarding the efficacy and tolerability of apomorphine, both in its established formulations (subcutaneous intermittent injection and continuous infusion) and in the new preparations currently under investigation.

Association of Parkinson's disease-related pain with plasma interleukin-1, interleukin-6, interleukin-10, and tumour necrosis factor-α

OBJECTIVE

To study the association between Parkinson's disease (PD)-related pain and plasma interleukin (IL)‑1, IL‑6, IL‑10, and tumour necrosis factor (TNF)‑α levels.

METHODS

Sixty-seven participants were enrolled. Plasma inflammatory cytokine levels of IL-1, IL-6, IL-10, and TNF-α were measured with enzyme-linked immunosorbent assay. We additionally administered the third part of the Unified Parkinson's Disease Rating Scale (UPDRS III) and Hoehn and Yahr (H-Y) scale stage and recorded the course of the disease, the type and location of the pain, and the use of drugs.

RESULTS

The level of IL-1 was significantly higher in the PD-with-pain than in the healthy-control group (P < 0.05). There was no significant difference among groups in the other examined cytokine levels. There was a statistically significant difference between the PD-with-pain and the PD-without-pain groups in UPDRS III and H-Y stage. Additionally, the IL-1 level was significantly higher in patients who received a levodopa dosage of >250 mg than in their counterparts who received ≤250 mg, and the IL-1 level was higher in patients with an H-Y stage of >2 and UPDRS III of >27 than in their counterparts with an H-Y stage of ≤2 and UPDRS III of ≤27. The expression of TNF-α was higher in patients aged ≥70 years than in their counterparts aged <70 years. The level of IL-10 was significantly lower in the patients with an H-Y stage of >2 than in their counterparts with an H-Y stage of ≤2.

CONCLUSION

The elevated level of IL-1 and the depressed level of IL-10 in the peripheral blood of patients with PD-related pain suggests that certain inflammatory cytokines may be implicated in the occurrence and clinical symptoms of PD-related pain.