Nonmotor symptoms of Parkinson’s disease

Assessing the reproducibility of machine-learning-based biomarker discovery in Parkinson's disease

Feature selection and machine learning algorithms can be used to analyze Single Nucleotide Polymorphisms (SNPs) data and identify potential disease biomarkers. Reproducibility of identified biomarkers is critical for them to be useful for clinical research; however, genotyping platforms and selection criteria for individuals to be genotyped affect the reproducibility of identified biomarkers. To assess biomarkers reproducibility, we collected five SNPs datasets from the database of Genotypes and Phenotypes (dbGaP) and explored several data integration strategies. While combining datasets can lead to a reduction in classification accuracy, it has the potential to improve the reproducibility of potential biomarkers. We evaluated the agreement among different strategies in terms of the SNPs that were identified as potential Parkinson's disease (PD) biomarkers. Our findings indicate that, on average, 93% of the SNPs identified in a single dataset fail to be identified in other datasets. However, through dataset integration, this lack of replication is reduced to 62%. We discovered fifty SNPs that were identified at least twice, which could potentially serve as novel PD biomarkers. These SNPs are indirectly linked to PD in the literature but have not been directly associated with PD before. These findings open up new potential avenues of investigation.

Gender discrepancies and differences in motor and non-motor symptoms, cognition, and psychological outcomes in the treatment of Parkinson's disease with subthalamic deep brain stimulation

Available data suggest that there may be gender differences in the effect of STN-DBS in the treatment of Parkinson's disease (PD). The aim of this study was to review data on gender discrepancies and gender differences in clinical outcomes in PD patients treated with deep brain stimulation of the subthalamic nucleus (STN-DBS). Included were original studies that specifically examined gender discrepancies or gender differences in PD patients with STN-DBS. Men receive more DBS than women, for various indications. The decision-making process for DBS in women compared to men is more influenced by personal preferences and external factors. Motor symptoms improve in both genders, but bradykinesia improves more in men. The postoperative reduction of the levodopa equivalent daily dose seems to be more pronounced in men. Men show more cognitive deterioration and less improvement than women after STN-DBS. Women show more depressive symptoms before surgery, but they improve similarly to men. Men show more improvement in impulsivity and less decrease in impulsive behaviour symptoms than women. Anxiety and personality traits remain unchanged in both genders. Voice quality improves more in men and deteriorates less often than in women. Men gain fat-free mass and fat mass, but women only gain fat mass. Regarding sexual function the evidence is inconsistent. More urinary symptoms improve in women than in men. Pain and restless leg syndrome seems to improve more in men. Regarding quality of life, the evidence seems to be inconsistent, and activities of daily living seems to improve in both genders. Better prospective controlled studies, focusing directly on gender differences in PD patients treated with STN-DBS, are needed to better explain gender differences in STN-DBS for PD.

Designing environments that contribute to a reduction in the progression of Parkinson's disease; a literature review

Parkinson's Disease (PD), a prevalent neurological disorder, causes physical difficulties like stiffness and impaired walking and affects patients' emotional well-being. Regular exercise and exposure to enriched environments are crucial to managing these symptoms. This review aims to extract evidence from studies regarding built environments' impact on reducing the progression of PD. Keywords from 2005 to 2022 were used in five databases, including PubMed, Clarivate Web of Science, UGA Library, and Google Scholar. Many studies emphasized physiotherapy and training for physical enhancement, often utilizing virtual games and smart devices. Others highlighted the advantages of non-slip flooring and accessible outdoor spaces, with some based on universal design principles. Few studies considered the emotional impact of built environments, showing a considerable gap in the studies simultaneously evaluating psychological and physical perspectives of Parkinson-friendly environments. There needs to be more consistency when considering these aspects of planning. Our findings suggest future research modeling enriched environments and tracking their impact on patients via Virtual Reality to find a comprehensive guideline for the most effective PD management environments.

Cingulum and Uncinate Fasciculus Microstructural Abnormalities in Parkinson's Disease: A Systematic Review of Diffusion Tensor Imaging Studies

Diffusion tensor imaging (DTI) is gaining traction in neuroscience research as a tool for evaluating neural fibers. The technique can be used to assess white matter (WM) microstructure in neurodegenerative disorders, including Parkinson disease (PD). There is evidence that the uncinate fasciculus and the cingulum bundle are involved in the pathogenesis of PD. These fasciculus and bundle alterations correlate with the symptoms and stages of PD. PRISMA 2022 was used to search PubMed and Scopus for relevant articles. Our search revealed 759 articles. Following screening of titles and abstracts, a full-text review, and implementing the inclusion criteria, 62 papers were selected for synthesis. According to the review of selected studies, WM integrity in the uncinate fasciculus and cingulum bundles can vary according to symptoms and stages of Parkinson disease. This article provides structural insight into the heterogeneous PD subtypes according to their cingulate bundle and uncinate fasciculus changes. It also examines if there is any correlation between these brain structures' structural changes with cognitive impairment or depression scales like Geriatric Depression Scale-Short (GDS). The results showed significantly lower fractional anisotropy values in the cingulum bundle compared to healthy controls as well as significant correlations between FA and GDS scores for both left and right uncinate fasciculus regions suggesting that structural damage from disease progression may be linked to cognitive impairments seen in advanced PD patients. This review help in developing more targeted treatments for different types of Parkinson's disease, as well as providing a better understanding of how cognitive impairments may be related to these structural changes. Additionally, using DTI scans can provide clinicians with valuable information about white matter tracts which is useful for diagnosing and monitoring disease progression over time.

An Update on Peripheral Blood Extracellular Vesicles as Biomarkers for Parkinson's Disease Diagnosis

Parkinson's disease (PD) is the world's second primary neurodegenerative disease, and the diagnosis and treatment of PD have become mainstream research. Over the past decades, several studies have identified potential biomarkers for diagnosing PD. Among them, extracellular vesicles (EVs) can carry specific biomarkers reflecting the physiological and pathological state of the body. Due to the blood-brain barrier (BBB) limitation, peripheral blood is limited in diagnosing neurodegenerative diseases. With the increasing research on EVs, their ability to pass through BBB indicated that peripheral blood could depict disease status like cerebrospinal fluid (CSF). Peripheral blood is a clinically available sample and has recently been widely used by researchers in various studies. In this review, we summarized previous studies on PD diagnosis biomarkers in peripheral blood EVs and evaluated their diagnostic value. Some EV surface markers were also described, which can extract EVs from specific cell origins. In addition, the combination of several biomarkers demonstrated good diagnostic performance in PD diagnosis compared with a single biomarker, suggesting the focus of future research.

GaitForeMer: Self-Supervised Pre-Training of Transformers via Human Motion Forecasting for Few-Shot Gait Impairment Severity Estimation

Parkinson's disease (PD) is a neurological disorder that has a variety of observable motor-related symptoms such as slow movement, tremor, muscular rigidity, and impaired posture. PD is typically diagnosed by evaluating the severity of motor impairments according to scoring systems such as the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS). Automated severity prediction using video recordings of individuals provides a promising route for non-intrusive monitoring of motor impairments. However, the limited size of PD gait data hinders model ability and clinical potential. Because of this clinical data scarcity and inspired by the recent advances in self-supervised large-scale language models like GPT-3, we use human motion forecasting as an effective self-supervised pre-training task for the estimation of motor impairment severity. We introduce GaitForeMer, Gait Forecasting and impairment estimation transforMer, which is first pre-trained on public datasets to forecast gait movements and then applied to clinical data to predict MDS-UPDRS gait impairment severity. Our method outperforms previous approaches that rely solely on clinical data by a large margin, achieving an F1 score of 0.76, precision of 0.79, and recall of 0.75. Using GaitForeMer, we show how public human movement data repositories can assist clinical use cases through learning universal motion representations. The code is available at https://github.com/markendo/GaitForeMer.

Differences Between Exergaming Rehabilitation and Conventional Physiotherapy on Quality of Life in Parkinson's Disease: A Systematic Review and Meta-Analysis

Parkinson's disease (PD) is a neurodegenerative condition with both motor and non-motor symptoms affecting the quality of life (QoL) of older adults. Exergaming rehabilitation allows the interaction of the subject with digital games through the implementation of repetitive functional activities. Conventional physiotherapy uses patient-centered programs that include a variety of active exercises. The aim of this review was to look into the effectiveness of exergaming rehabilitation on the QoL of people with PD and compare it with conventional physiotherapy. Five electronic databases were searched for eligible studies until February 2021. For the statistical analysis, the mean, standard deviation, and 95% confidence interval were used to calculate effect sizes between groups. To determine heterogeneity, statistical index I ² was used. A total of 548 participants were included in 14 studies. Exergaming rehabilitation related with improved QoL (p = 0.687, 95% CI: -1.682 to -0.734), balance (p = 0.039, 95% CI: 0.364-13.689), (p = 0.018, 95% CI: 0.446-4.830), and gait (p = 0.005, 95% CI: 0.351-1.924). No significant difference was found between groups regarding the Unified Parkinson's Disease Rating Scale (p = 0.196, 95% CI: -5.970 to 1.225) and for the Timed Up and Go Test (p = 0.12, 95% CI: 0.446-4.830). Exergames as a rehabilitation method can be used to provide alternative interactive intervention with positive results for QoL in people with PD. Further investigation is needed to assess the effect on mental health in this population group.

Reasons for hospitalization and factors of mortality in patients with Parkinson's disease in the Philippines

Aim: We aimed to determine the reasons for hospitalizations and factors of mortality of Filipino Parkinson's disease (PD) patients in a tertiary hospital. Methods: We conducted a retrospective review of medical records of PD patients admitted to our institution between 2016 and 2018. Demographic and clinical data were analyzed. Results: We included 166 PD patients. The most common cause of admission was infectious (pneumonia, urinary tract, and skin-soft tissue infections) (n = 65, 39.2%). The most common cause of mortality was sepsis (n = 9, 5.4%). Renal comorbidity was a significant factor of mortality (OR: 3.67, 95% CI: 1.11-12.12; p = 0.033). Conclusion: Interventions designed to reduce the risk of complications in PD patients should be prioritized to potentially decrease the probability of eventual hospitalization.

Machine Learning for the Diagnosis of Parkinson's Disease: A Review of Literature

Diagnosis of Parkinson's disease (PD) is commonly based on medical observations and assessment of clinical signs, including the characterization of a variety of motor symptoms. However, traditional diagnostic approaches may suffer from subjectivity as they rely on the evaluation of movements that are sometimes subtle to human eyes and therefore difficult to classify, leading to possible misclassification. In the meantime, early non-motor symptoms of PD may be mild and can be caused by many other conditions. Therefore, these symptoms are often overlooked, making diagnosis of PD at an early stage challenging. To address these difficulties and to refine the diagnosis and assessment procedures of PD, machine learning methods have been implemented for the classification of PD and healthy controls or patients with similar clinical presentations (e.g., movement disorders or other Parkinsonian syndromes). To provide a comprehensive overview of data modalities and machine learning methods that have been used in the diagnosis and differential diagnosis of PD, in this study, we conducted a literature review of studies published until February 14, 2020, using the PubMed and IEEE Xplore databases. A total of 209 studies were included, extracted for relevant information and presented in this review, with an investigation of their aims, sources of data, types of data, machine learning methods and associated outcomes. These studies demonstrate a high potential for adaptation of machine learning methods and novel biomarkers in clinical decision making, leading to increasingly systematic, informed diagnosis of PD.

Sex-specific effects of subthalamic nucleus stimulation on pain in Parkinson's disease

OBJECTIVE

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is known to reduce motor symptoms of Parkinson's disease (PD). The effects of DBS on various nonmotor symptoms often differ from patient to patient. The factors that determine whether or not a patient will respond to treatment have not been elucidated. Here, the authors evaluated sex differences in pain relief after DBS for PD.

METHODS

The authors prospectively evaluated 20 patients preoperatively and postoperatively after bilateral STN DBS with the validated numeric rating scale (NRS), Revised Oswestry Disability Index for low-back pain (RODI), and King's Parkinson's Disease Pain Scale (KPDPS) and assessed the impact of sex as a biological variable.

RESULTS

The cohort consisted of 6 female and 14 male patients with a mean duration of 11.8 ± 2.0 months since DBS surgery. Females were significantly older (p = 0.02). Covariate analysis, however, showed no effect of age, stimulation settings, or other confounding variables. KPDPS total scores statistically significantly improved only among males (p < 0.001). Males improved more than females in musculoskeletal and chronic subsets of the KPDPS (p = 0.03 and p = 0.01, respectively). RODI scores significantly improved in males but not in females (p = 0.03 and p = 0.30, respectively). Regarding the NRS score, the improvements seen in both sexes in NRS were not significant.

CONCLUSIONS

Although it is well recognized that pain complaints in PD are different between men and women, this study is unique in that it examines the sex-specific DBS effects on this symptom. Considering sex as a biological variable may have important implications for DBS pain outcome studies moving forward.

The class II histone deacetylases as therapeutic targets for Parkinson's disease

Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterised by specific motor impairments. The neuropathological hallmarks of PD include progressive degeneration of midbrain dopaminergic neurons, and loss of their axonal projections to the striatum. Additionally, there is progressive accumulation and spread of intracellular aggregates of α-synuclein. Although dopamine-replacement pharmacotherapy can treat PD symptoms in the short-term, there is a critical need for the development of disease-modifying therapies based on an understanding of the underlying disease mechanisms. One such mechanism is histone acetylation, which is a common epigenetic modification that alters gene transcription. A number of studies have described alterations in histone acetylation in the brains of PD patients. Moreover, α-synuclein accumulation has been linked to alterations in histone acetylation and pharmacological strategies aimed at modulating histone acetylation are under investigation as novel approaches to disease modification in PD. Currently, such strategies are focused predominantly on pan-inhibition of histone deacetylase (HDAC) enzymes. Inhibition of specific individual HDAC enzymes is a more targeted strategy that may allow for future clinical translation. However, the most appropriate class of HDACs that should be targeted for neuroprotection in PD is still unclear. Recent work has shed new light on the role of class-II HDACs in dopaminergic degeneration. For this reason, here we describe the regulation of histone acetylation, outline the evidence for alterations in histone acetylation in the PD brain, and focus on the roles of class II HDACs and the potential of class-II HDAC inhibition as a therapeutic approach for neuroprotection in PD.

Influence of intranasal exposure of MPTP in multiple doses on liver functions and transition from non-motor to motor symptoms in a rat PD model

Besides the effects on the striatum, the impairment of visceral organs including liver functions has been reported in Parkinson's disease (PD) patients. However, it is yet unclear if liver functions are affected in the early stage of the disease before the motor phase has appeared. The aim of our present study was thus to assess the effect of intranasal administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in different doses on striatum and liver functions. Deterioration of non-motor activities appeared on single exposure to MPTP along with rise in striatum oxidative stress and decline in antioxidant levels. Decreases in dopamine, noradrenaline, and GABA and increase in serotonin were detected in striatum. Motor coordination was impaired with a single dose of MPTP, and with repeated MPTP exposure, there was further significant impairment. Locomotor activity was affected from second exposure of MPTP, and the impairment increased with third MPTP exposure. Impairment of liver function through increase in serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels was observed after first MPTP insult, and it worsened with second and third administrations. First administration of MPTP triggered systemic inflammation showing significant increase in inflammatory markers in the liver. Our data shows for the first time that an intranasal route of entry of MPTP affects liver from the non-motor phase of PD itself, occurring concomitantly with the reduction of striatal dopamine. It also suggests that a single dose is not enough to bring about progression of the disease from non-motor to locomotor deficiency, and a repeated dose is needed to establish the motor severity phase in the rat intranasal MPTP model.

Treatment of psychiatric disturbances in hypokinetic movement disorders

Introduction: We reviewed studies that assessed the treatment of psychiatric disturbances in Parkinson's disease and atypical parkinsonisms. Neuropsychiatric disturbances in these conditions are frequent and have a profound impact on quality of life of patients and of their caregivers. It is therefore important to be familiar with the appropriate pharmacological and non-pharmacological interventions for treating these disorders. Areas covered: The authors searched for papers in English in Pubmed using the following keywords: Parkinson's disease, multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration, Lewy body dementia, depression, apathy, anxiety, fatigue, sleep disorders, obsessive compulsive disorders, psychosis, hallucinations, delusions, impulse control disorders. Expert opinion: In Parkinson's disease, depression may benefit from the optimization of dopaminergic therapy, from the use of antidepressants acting on both the serotoninergic and noradrenergic pathways and from cognitive behavioral therapy. Psychosis in Parkinson's disease may improve with the use of clozapine; the serotonin inverse agonist pimavanserin has been shown to be effective. Treatment of impulse control disorders is primarily based on the removal of dopamine agonists. No controlled studies have investigated the treatment of neuropsychiatric disorders in multiple system atrophy, progressive supranuclear palsy or corticobasal degeneration. Acethylcholinesterase inhibitors may be used to treat hallucinations in Lewy body dementia.

Resistance Training Improves Sleep Quality in Subjects With Moderate Parkinson's Disease

Silva-Batista, C, de Brito, LC, Corcos, DM, Roschel, H, de Mello, MT, Piemonte, MEP, Tricoli, V, and Ugrinowitsch, C. Resistance training improves sleep quality in subjects with moderate Parkinson's disease. J Strength Cond Res 31(8): 2270-2277, 2017-The objectives of this study were to test if 12 weeks of progressive resistance training (RT) improves sleep quality and muscle strength in subjects with moderate Parkinson's disease (PD) and if sleep quality values of subjects with moderate PD are closer to those of age-matched healthy controls (HC) at posttraining. This was a randomized controlled trial conducted between March 2013 and September 2014. Twenty-two subjects with moderate PD were randomly assigned to a nonexercising control group (n = 11) or an RT group (n = 11). Thirty-one HC were not randomized to any group. The RT group performed a RT program twice a week for 12 weeks, whereas the control group made no change to their weekly routine. For subjects with PD, sleep quality (i.e., Pittsburgh Sleep Quality Index [PSQI]) and knee-extensor peak torque were assessed before and after 12 weeks of intervention; for HC, these outcomes were assessed at pretest only. There were differences between RT and control groups in PSQI scores, PSQI subscores(i.e., subjective sleep quality and daytime dysfunction), and knee-extensor peak torque at posttraining (p ≤ 0.05). After RT, the average subjects with PD showed lower (i.e., improved) PSQI scores than the average HC (p ≤ 0.05). A negative association was observed between changes in PSQI scores and changes in knee-extensor peak torque at posttraining (r = -0.58, p = 0.028). No adverse events were reported. The RT is recommended as an adjunct therapeutic method for improving sleep quality of subjects with moderate PD and moving these levels to those observed in HC.

Contribution of auditory P300 test to the diagnosis of mild cognitive impairment in Parkinson's disease

Abnormalities in auditory P300 test have been observed in patients with Parkinson's disease (PD). We aimed to investigate whether or not additional electrophysiological tests assist in making the clinical diagnosis of mild cognitive impairment in Parkinson's disease (PD-MCI), and we evaluated P300 changes in patients with non-demented PD and analyzed the correlation between the cognitive features and P300 changes. Twenty patients with PD who had been diagnosed with mild cognitive impairment (PD-MCI group) according to the Movement Disorder Society (MDS) 2012 PD-MCI level II criteria, 21 patients with PD without cognitive impairment (PD-Normal group), and 20 control subjects (control group) who were neurologically normal were examined by the standard auditory oddball paradigm. The N100, P200, N200, and P300 latencies and N100-P200, P200-N200, and N200-P300 amplitudes were measured and analyzed. P300 latencies recorded from Fz, Cz, and Pz and N200 latency recorded from Fz were significantly longer in the PD-MCI group than in the PD-Normal and the control group (respectively p < 0.001, p = 0.041). P300 amplitude recorded from Fz was significantly lower in PD-MCI group than those in the other groups (p = 0.038). While P300 was obtained in all patients in the PD-Normal and the control group, it was lost in 35% of PD-MCI patients. The results show that P300 provides a diagnostic tool for detecting PDMCI. We suggest that P300 prolongation and loss of P300 potential could be used as supportive parameter in the diagnosis of PD-MCI.

Developmental neuroplasticity and the origin of neurodegenerative diseases

OBJECTIVES

Neurodegenerative diseases like Alzheimer's and Parkinson's Disease, marked by characteristic protein aggregations, are more and more accepted to be synaptic disorders and to arise from a combination of genetic and environmental factors. In this review we propose our concept that neuroplasticity might constitute a link between early life challenges and neurodegeneration.

METHODS

After introducing the general principles of neuroplasticity, we show how adverse environmental stimuli during development impact adult neuroplasticity and might lead to neurodegenerative processes.

RESULTS

There are significant overlaps between neurodevelopmental and neurodegenerative processes. Proteins that represent hallmarks of neurodegeneration are involved in plastic processes under physiological conditions. Brain regions - particularly the hippocampus - that retain life-long plastic capacities are the key targets of neurodegeneration. Neuroplasticity is highest in young age making the brain more susceptible to external influences than later in life. Impacts during critical periods have life-long consequences on neuroplasticity and structural self-organization and are known to be common risk factors for neurodegenerative diseases.

CONCLUSIONS

Several lines of evidence support a link between developmental neuroplasticity and neurodegenerative processes later in life. A deeper insight into these processes is necessary to design strategies to mitigate or even prevent neurodegenerative pathologies.

Combined therapy of Di-Huang-Yi-Zhi with Donepezil in patients with Parkinson's disease dementia

Here we conducted a randomized and double-blind study attempting to explore the safety and efficacy of combined therapy of Di-Huang-Yi-Zhi (DHYZ) with donepezil in treating Parkinson's disease dementia (PDD). Sixty PDD patients were included and randomly divided into control group and DHYZ group. All patients were given donepezil (5 mg last for a month, then 10 mg for the rest months, once daily), while patients in DHYZ group were additionally administrated with DHYZ (150 ml, twice daily). The measurement subjects included mini-mental state examination (MMSE), Montreal cognitive assessment (MoCA), Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog), the Barthel Index for activities of daily living (ADL) and Traditional Chinese medical (TCM) symptoms before and after treatment in this study. The whole study lasted for six months. Significant differences were observed on MMSE, MoCA, ADAS-Cog, ADL and TCM in both control and DHYZ group (P<0.05 or P<0.01) before and after drug treatment. Furthermore, there were more obvious changes of MMSE, MoCA, ADAS-Cog, ADL and TCM scores compared the DHYZ group with the control group (P<0.01) which suggested the DHYZ group showed a more effective improvement on cognition, behavior as well global function. In conclusion, the combined therapy of DHYZ with donepezil showed a more effective improvement in PDD and the underlying mechanism may be related to the synergic amelioration of cholinergic system between them.

Critical appraisal of rotigotine transdermal system in management of Parkinson's disease and restless legs syndrome - patient considerations

Rotigotine (RTG) is a dopamine agonist that is used as mono and adjunct therapy to treat Parkinson’s disease, and as therapy for moderate-to-severe restless legs syndrome. RTG is the only dopamine agonist currently available as a 24-hour/day transdermal system, providing once-a-day dosing. As a transdermal patch, RTG bypasses the gastrointestinal tract, making it a treatment option for patients with dysphagia. The use of RTG also avoids the need to schedule administration of medication around meals. This review provides a critical appraisal of RTG as treatment of Parkinson’s disease and RLS.

Pain perception in patients with Parkinson's disease

Abnormalities in pain perception are a part of the clinical picture in Parkinson's disease (PD) and belong to the category of non-motor symptoms. Two groups of patients were included in this study: (i) an experimental group of 36 patients with PD who were eligible for subthalamic deep brain stimulation (the experimental group [EG]) and (ii) a control group (CG) of 34 patients with a space-occupying lesion who were admitted for a framed stereotactic biopsy. Stereotactic frame fixation was used in both groups as a nociceptive stimulus. All participants were assessed for pain perception with two kinds of visual analogue scales (VAS) (a non-color VAS [ncVAS] and a color VAS [cVAS]) immediately after the stimulus (EG - ncVAS 1 and cVAS 1; CG - ncVAS 3 and cVAS 3) and 24 hours later (EG - ncVAS 2 and cVAS 2; CG - ncVAS 4 and cVAS 4). The means for the two pain scores assessed directly after frame fixation were 3.59 (ncVAS 1) and 3.06 (cVAS 1) for patients in the EG, while the mean ncVAS was 3, and the mean cVAS 3 was 6.1 for those in the CG. The pain intensity was significantly lower for patients with PD (EG) compared to those in the CG for both ncVAS and cVAS (p<0.05 for each measure). The mean pain scores for ncVAS and cVAS measured 24 hours after the procedure were 3.18 and 2.79 for patients with PD (EG) and 6.10 and 5.77 for those in the CG, respectively. Pain intensity measured 24 hours after the procedure was significantly lower in those with PD (EG) compared to the CG. This study has demonstrated that pain perception in patients with PD is significantly lower than pain perception in non-parkinsonian patients.

Neural and immune mechanisms in the pathogenesis of Parkinson's disease

Although almost 50 years have passed since impaired dopaminergic transmission was identified as the main neurochemical defect in Parkinson's disease (PD), the cause of the disease remains unknown. A restricted number of biological mechanisms are likely to contribute to the process of cell death in the nigrostriatal pathway. These mechanisms include mitochondrial defects and enhanced formation of reactive oxygen species--leading to oxidative damage--and abnormal protein aggregation. In addition to or, possibly, intermingled with these mechanisms of neuronal damage there is another crucial factor: neuroinflammation. The inflammatory response associated with cell loss in the dopaminergic nigrostriatal tract and, more in general, the role of immune mechanisms are increasingly recognized in PD pathogenesis. Neuroinflammatory changes have been repeatedly demonstrated, in both neurotoxic and transgenic animal models of PD, as well as in PD patients. Transgenic models based on α-synuclein overexpression, in particular, have provided crucial insights into the correlation between this protein and the dichotomous response that microglia can activate, with the polarization toward a cytotoxic (M1) or cytoprotective (M2) phenotype. Full understanding of such mechanisms may set the ground for a fine tuning of the neuroinflammatory process that accompanies and sustains neurodegeneration, thereby opening new therapeutic perspectives for PD.

Parkinson's disease: a complex interplay of mitochondrial DNA alterations and oxidative stress

Parkinson’s disease (PD) is one of the most common age-related neurodegenerative diseases. This pathology causes a significant loss of dopaminergic neurons in the Substantia Nigra. Several reports have claimed a role of defective nuclear and mitochondrial DNA repair pathways in PD etiology, in particular, of the Base Excision Repair (BER) system. In addition, recent findings, related to PD progression, indicate that oxidative stress pathways involving c-Abl and GST could also be implicated in this pathology. This review focuses on recently described networks most likely involved in an integrated manner in the course of PD.

Strategies for Parkinson’s disease care: prevention and management of motor fluctuations

SUMMARY Parkinson’s disease (PD) is characterized clinically by the hallmark motor signs of bradykinesia, rest tremor and rigidity. Current pharmacological management goals include control of motor symptoms as well as prevention and management of motor complications including motor fluctuations and dyskinesias. While the use of levodopa revolutionized the pharmacological management of PD, multiple other agents and strategies have emerged with many demonstrable, albeit sometimes controversial, advantages to a ‘levodopa’ only approach. Despite these developments, the progressive nature of PD requires vigilance and creativity from clinicians as both motor and nonmotor complications grow in number and severity over time.

Lees' syndrome: a case series

We report a case series of dopamine dysregulation syndrome, previously known as hedonistic homeostatic dysregulation in patients with Parkinson's disease on dopamine replacement therapies, now designated as Lees' syndrome.

Psychometric validation of the revised SCOPA-Diary Card: expanding the measurement of non-motor symptoms in Parkinson's disease

Background

To identify key non-motor symptoms of Parkinson's disease (PD) to include in a daily diary assessment for off-time, revise the Scales for Outcomes of Parkinson's disease Diary Card (SCOPA-DC) to include these non-motor symptoms, and investigate the validity, reliability and predictive utility of the Revised SCOPA-DC in a U.S. population.

Methods

A convenience sample was used to recruit four focus groups of PD patients. Based on findings from focus groups, the SCOPA-DC was revised and administered to a sample of 101 PD patients. Confirmatory factor analysis was conducted to test the domain structure of the Revised SCOPA-DC. The reliability, convergent and discriminant validity, and ability to predict off-time of the Revised SCOPA-DC were then assessed.

Results

Based on input from PD patients, the Revised SCOPA-DC included several format changes and the addition of non-motor symptoms. The Revised SCOPA-DC was best represented by a three-factor structure: Mobility, Physical Functioning and Psychological Functioning. Correlations between the Revised SCOPA-DC and other Health-Related Quality of Life scores were supportive of convergent validity. Known-groups validity analyses indicated that scores on the Revised SCOPA-DC were lower among patients who reported experiencing off-time when compared to those without off-time. The three subscales had satisfactory predictive utility, correctly predicting off-time slightly over two-thirds of the time.

Conclusions

These findings provide evidence of content validity of the Revised SCOPA-DC and suggest that a three-factor structure is an appropriate model that provides reliable and valid scores to assess symptom severity among PD patients with symptom fluctuations in the U.S.

Nonmotor symptoms are independently associated with impaired health-related quality of life in Chinese patients with Parkinson's disease

We performed a cross-sectional study of 82 Chinese patients with Parkinson's disease (PD) enrolled during an 18-month period using a clinical interview to assess the prevalence of nonmotor symptoms (NMS), the association with disease severity and motor status, and the impact on patients' health-related quality of life (Hr-QoL). The patients' NMS, Hr-QoL, disease severity, and motor status were assessed by the Nonmotor Symptoms Scale (NMSS), the 39-item Parkinson's Disease Questionnaire (PDQ-39), the modified Hoehn and Yahr staging scale (H&Y) and the Unified Parkinson's Disease Rating Scale part III (UPDRS III), respectively. We found that 100% of patients with PD presented with NMS. The NMSS significantly correlated with disease duration (Spearman's r(S) = 0.276, P = 0.012), H&Y (r(S) = 0.230, P = 0.038), and UPDRS III (r(S) = 0.350, P = 0.001). Similarly, the PDQ-39 SI significantly associated with the disease duration (r(S) = 0.258, P = 0.019), H&Y (r(S) = 0.340, P = 0.002), and UPDRS III (r(S) = 0.453, P < 0.001). NMS domains that influenced the PDQ-39 SI were sleep/fatigue, mood, gastrointestinal, urinary, and miscellaneous symptoms. This strongly suggested that the five domains played a key role in the manifestation of Hr-QoL. NMSS explains more of the variability in Hr-QoL than UPDRS III, when both are the model (stepwise multiple linear regression analysis R² change, 47.8% vs. 5.87%, respectively). Therefore, these findings demonstrate that NMS are independently and negatively associated with Hr-QoL in PD and that improving NMS should be viewed as an important part in the management of PD.

Parkinson's disease dementia

Dementia associated with Parkinson's disease (PDD) is a common problem and one that is associated with significant morbidity and mortality. Over the past decade, increasing research efforts and funding have been directed toward an improved understanding of PDD. Despite these efforts, fundamental gaps remain in our knowledge. Consequently, therapeutic progress has been frustratingly slow and incomplete. To significantly affect PDD, novel "disease-modifying" agents, rather than more traditional neurotransmitter replacement approaches, likely will be required.

Behavioral phenotyping of mouse models of Parkinson's disease

Parkinson's disease (PD) is a common neurodegenerative movement disorder afflicting millions of people in the United States. The advent of transgenic technologies has contributed to the development of several new mouse models, many of which recapitulate some aspects of the disease; however, no model has been demonstrated to faithfully reproduce the full constellation of symptoms seen in human PD. This may be due in part to the narrow focus on the dopamine-mediated motor deficits. As current research continues to unmask PD as a multi-system disorder, animal models should similarly evolve to include the non-motor features of the disease. This requires that typically cited behavioral test batteries be expanded. The major non-motor symptoms observed in PD patients include hyposmia, sleep disturbances, gastrointestinal dysfunction, autonomic dysfunction, anxiety, depression, and cognitive decline. Mouse behavioral tests exist for all of these symptoms and while some models have begun to be reassessed for the prevalence of this broader behavioral phenotype, the majority has not. Moreover, all behavioral paradigms should be tested for their responsiveness to L-DOPA so these data can be compared to patient response and help elucidate which symptoms are likely not dopamine-mediated. Here, we suggest an extensive, yet feasible, battery of behavioral tests for mouse models of PD aimed to better assess both non-motor and motor deficits associated with the disease.

Fatigue in Parkinson disease, stroke, and traumatic brain injury

Fatigue is a serious, QoL-limiting symptom of many neurologic conditions. Physicians should be thorough and consistent in their assessment for this problem and not let motor symptoms monopolize an office visit. Although the use of pharmacology to treat this problem has predominantly only anecdotal evidence of efficacy, several nonpharmacologic interventions may prove helpful. The directions of future research should aim to create clear treatment guidelines using the pharmacologic agents available.

Parkinson's disease and resistive exercise: rationale, review, and recommendations

Individuals with Parkinson's disease (PD) are not only burdened with disease-specific symptoms (i.e., bradykinesia, rigidity, and tremor), but are also confronted with age-associated progressive loss of physical function, perhaps to a greater extent than neurologically normal adults. Suggestions for the inclusion of resistive exercise into treatment to attenuate these symptoms were made over 10 years ago, yet very few well controlled investigations are available. The objective of this review is to establish a clear rationale for the efficacy of resistance training in individuals with PD. Specifically, we highlight musculoskeletal weakness and its relationship to function as well as potential training-induced adaptive alterations in the neuromuscular system. We also review the few resistance training interventions currently available, but limit this review to those investigations that provide a quantitative exercise prescription. Finally, we recommend future lines of inquiry warranting further attention and call to question the rationale behind current exercise prescriptions. The absence of reports contraindicating resistive exercise, the potential for positive adaptation, and the noted benefits of resistance training in other populations may provide support for its inclusion into a treatment approach to PD.