The neuropsychiatry of Parkinson's disease: advances and challenges

Effects of Meditation and Yoga on Anxiety, Depression and Chronic Inflammation in Patients with Parkinson's Disease: A Randomized Clinical Trial

INTRODUCTION

Clinical guidelines recommend a holistic approach to Parkinson's disease (PD) care, yet randomized trials examining mindfulness-based interventions in this context are scarce. This study investigated the effects of two mindfulness practices - meditation and yoga - on biopsychosocial outcomes in PD patients, including anxiety symptoms, depressive symptoms, motor/nonmotor symptoms, health-related quality-of-life (HRQOL), mindfulness, and stress and inflammation biomarkers, compared to usual care.

METHODS

159 participants with a clinical diagnosis of idiopathic PD and a Hoehn and Yahr stage of 1, 2, and 3, were randomized into meditation (n = 53), yoga (n = 52), and control (n = 54). Meditation and yoga were delivered in 90-min groups for 8 weeks. Primary outcomes included anxiety symptoms and depressive symptoms. Secondary outcomes included motor and nonmotor symptoms, HRQOL, mindfulness, and serum levels of interleukin-6, cortisol and TNF-alpha. Assessments were done at baseline (T0), 2 months (T1), and 6 months (T2). Linear mixed models were conducted following intention-to-treat principle.

RESULTS

Compared to control, both meditation, and yoga groups had significant improvements in anxiety symptoms (meditation: mean difference [MD] = -1.36, 95% CI: -2.46 to-0.26; yoga: MD = -1.61, CI: -2.70 to -0.52), motor symptoms (meditation: MD = -5.35, CI: -8.61 to-2.09; yoga: MD = -6.59, CI: -9.82 to-3.36), HRQOL (meditation: MD = -2.01, CI: -3.41 to-0.62; yoga: MD = -1.45, CI: -2.83 to-0.08), and describing skills (meditation: MD = 0.97, CI: 0.04-1.89; yoga: MD = 0.92, CI: 0.01-1.84) at T1, and significant reductions in serum interleukin-6 levels (meditation: MD = -1.14, CI: -2.18 to-0.10; yoga: MD = -1.11, CI: -2.09 to-0.13) at T2. Only meditation significantly reduced depression (MD = -1.44, CI: -2.57 to-0.30) at T1 and sustained the motor and HRQOL improvements at T2.

CONCLUSION

Meditation and yoga significantly improved anxiety symptoms, chronic inflammation, motor symptoms, mindfulness-describing facet, and HRQOL in PD patients. Meditation provided additional benefits in reducing depressive symptoms and sustaining motor and HRQOL improvements.

Classification of Parkinson's disease with and without dopaminergic deficiency based on non-motor symptoms and structural neuroimaging

The presence of non-motor symptoms (NMS) such as olfactive deficit or neuropsychiatric symptoms has been associated with the diagnosis of Parkinson's Disease (PD). NMS are also associated with different brain structural features underlying distinctive processes in PD. NMS has been poorly studied in patients with a PD-like clinical profile, showing Scans Without Evidence of Dopaminergic Deficit (SWEDD). This study proposes to compare classification models differentiating PD, SWEDD and Healthy Controls (HC) based on NMS and neurostructural factors. 683 participants (382 PD diagnosed in the last 2 years, 48 with SWEDD, 170 HC) from the PPMI dataset were compared based on available assessments. Each participant underwent an olfactive, neuropsychiatric and sleep assessment, and a 3T MRI. Brain volumes were extracted and standardized from each MRI. Classifications were based on logistic regressions using 5-fold cross-validation models combining different NMS and MRI data and determining their involvement in differentiation between patient subgroups (PD vs. SWEDD) or between patients and HC. NMS were significant factors in PD vs. SWEDD, PD vs. HC and SWEDD vs. HC classifiers, when considered alone or in combination with MRI data. No classification models were significantly different from chance based-on MRI, nor more accurate combining NMS and MRI when compared with models based on NMS only. These results highlight the importance of NMS in differentiating between PD and SWEDD, PD and HC, SWEDD and HC. However, classical imaging data such as cortical and subcortical volumetry seems insufficient to improve these classifications. Other imaging features such as connectivity could also be studied.

Synergistic Anti-Ferroptosis with a Minimalistic, Peroxide-Triggered Carbon Monoxide Donor for Parkinson's Disease

Parkinson's disease (PD) is a debilitating neurodegenerative disease, with current treatments primarily focusing on improving dopaminergic activity, providing symptomatic relief but failing to halt disease progression. Ferroptosis drives PD pathogenesis and is a potential therapeutic target. Herein, we introduce a novel peroxide-activated carbon monoxide (CO) donor, PCOD, featuring a streamlined structure designed to potentially enhance blood-brain barrier (BBB) penetration and optimize therapeutic outcomes. PCOD releases CO upon activation by nucleophilic peroxides, e.g., ONOO- and H2O2. This mechanism provides a potent strategy against ferroptosis: first, scavenging peroxides that generate oxidative radicals involved in ferroptosis, and second, CO is proposed to inhibit Fenton chemistry through coordination to Fe2+. In MPTP-treated mice, PCOD prevents dopaminergic neuron loss in the substantia nigra and alleviates PD symptoms. This peroxide-triggered CO release offers a promising and innovative strategy to combat ferroptosis and neurodegeneration in PD.

Perceptions of digitally supported home exercise for people with Parkinson's disease: A qualitative study

BACKGROUND

Digitally supported home exercise offers the potential to expand accessibility to rehabilitation. However, little is known about how people with Parkinson's disease experience performing home exercise programs using digital delivery.

OBJECTIVE

To explore and describe how people with Parkinson's disease perceive digital home-based exercise that is not supported in real-time, and how it affected their everyday lives.

METHODS

This study was qualitative in nature, using qualitative content analysis with an inductive approach. In-depth, individual, semi-structured interviews were held with 14 participants with Parkinson's disease.

RESULTS

Two overarching themes were formed: "Active agency in the face of uncertainty" and "The home - safe space or disability on display". The overarching themes were formed by four themes: 1) resisting the disease - a hope and a burden, 2) interpreting mixed messages, 3) home exercise - consideration and responsibility, and 4) the social context - judgement and support. Participants with Parkinson's disease believe that home exercise enables them to actively counter the disease, and this belief serves as both a source of hope but also a burden. Although perceived as advantageous, digitally supported home exercise may also incur becoming vulnerable to exposing one's disability.

CONCLUSIONS

People with Parkinson's disease struggle to reconcile their beliefs about exercise with that which is encouraged or discouraged by those around them. Exercise in the home involves a dynamic interplay between achieving self-directed goals while trying to balance social consideration and maintaining integrity of identity.

Nanotechnology in Parkinson's Disease: overcoming drug delivery challenges and enhancing therapeutic outcomes

The global prevalence of Parkinson's Disease (PD) is on the rise, driven by an ageing population and ongoing environmental conditions. To gain a better understanding of PD pathogenesis, it is essential to consider its relationship with the ageing process, as ageing stands out as the most significant risk factor for this neurodegenerative condition. PD risk factors encompass genetic predisposition, exposure to environmental toxins, and lifestyle influences, collectively increasing the chance of PD development. Moreover, early and precise PD diagnosis remains elusive, relying on clinical assessments, neuroimaging techniques, and emerging biomarkers. Conventional management of PD involves dopaminergic medications and surgical interventions, but these treatments often become less effective over time and do not address disease treatment. Challenges persist due to the blood-brain barrier's (BBB) impermeability, hindering drug delivery. Recent advancements in nanotechnology offer promising novel approaches for PD management. Various drug delivery systems (DDS), including nanosized polymers, lipid-based carriers, and nanoparticles (such as metal/metal oxide, protein, and carbonaceous particles), aim to enhance drug and gene delivery. These modifications seek to improve BBB permeability, ultimately benefiting PD patients. This review underscores the critical role of ageing in PD development and explores how age-related neuronal decline contributes to substantia nigra loss and PD manifestation in susceptible individuals. The review also highlights the advancements and ongoing challenges in nanotechnology-based therapies for PD.

The role of the immune system in Parkinson's disease pathogenesis: A focus on Th17 cells - A systematic review and meta-analysis

BACKGROUND

Parkinson's disease (PD) has been linked to T helper 17 (Th17) cells in prior investigations, but the evidence remains inconclusive. To gain a deeper understanding of this potential connection, we conducted a systematic review and meta-analysis.

METHODS

A comprehensive search for relevant studies published up to July 8, 2023, was performed across PubMed, EMBASE, and Cochrane Library databases. A random-effect model was employed to synthesize effect sizes and their corresponding 95 % confidence intervals (CIs). Leave-one-out sensitivity analysis and funnel plots with trim-and-fill were utilized to assess the combined results' robustness.

RESULTS

Thirteen studies were ultimately included in the meta-analysis. Pooled effect sizes indicated a significantly higher percentage of Th17 cells in PD patients (Standardized Mean Difference [SMD] = 1.00, 95 % CI 0.30-1.71). Notably, Th17 cell levels were more elevated in Asian PD patients (SMD = 1.33, 95 % CI 0.31-2.35). Additionally, the percentage of Th17 cells positively correlated with Movement Disorder Society Unified Parkinson's Disease Rating Scale-III (UPDRS-III) scores (r = 0.22, 95 % CI 0.01-0.41), indicating a link to motor dysfunction. Conversely, a negative correlation was observed with Cognitive function scale scores (r = - 0.27, 95 % CI -0.47--0.04), suggesting a potential association with cognitive decline.

CONCLUSIONS

This study revealed a positive association between Th17 cells and PD, with PD patients exhibiting elevated Th17 levels. Furthermore, the percentage of Th17 cells correlated with motor and cognitive impairments in PD patients.

Benefits of a 12-week psychotherapy course for people with Parkinson's disease: a service improvement project

The psychological symptoms of Parkinson's disease (PD) worsen the quality of life of patients and their partners. However, these non-motor symptoms (mainly anxiety and depression) remain undiagnosed and undertreated in PD. Here, we report the benefits of a 12-week intervention using talking therapy (psychotherapy and counselling). This work was conducted in a group of individuals (people living with PD, and partners) with mild-to-moderate anxiety and depression. We discuss our results in context and conclude that short-term talking therapy should be integrated into PD therapeutics.

Genetic analyses identify circulating genes related to brain structures associated with Parkinson's disease

Magnetic resonance imaging and circulating molecular testing are potential methods for diagnosing and treating Parkinson's disease (PD). However, their relationships remain insufficiently studied. Using genome-wide association summary statistics, we found in the general population a genetic negative correlation between white matter tract mean diffusivity and PD (-0.17 < Rg < -0.11, p < 0.05), and a positive correlation with intracellular volume fraction (0.12 < Rg < 0.2, p < 0.05). Additionally, 1345 circulating genes causally linked with white matter tract diffusivity were enriched for muscle physiological abnormalities (padj < 0.05). Notable genes, including LRRC37A4P (effect size = 15.7, p = 1.23E-55) and KANSL1-AS1 (effect size = -15.3, p = 1.13E-52), were directly associated with PD. Moreover, 23 genes were found linked with genetically correlated PD-IDP pairs (PPH4 > 0.8), including SH2B1 and TRIM10. Our study bridges the gap between molecular genetics, neuroimaging, and PD pathology, and suggests novel targets for diagnosis and treatment.

A study on the exploration of mild cognitive impairment in Parkinson's disease based on decision-making cognitive computing

Mild cognitive impairment in Parkinson's disease (PD-MCI) as an independent risk factor for dementia in Parkinson's disease has prognostic value in predicting dementia in PD patients. It was found that the calculation of cognitive function decision-making could better evaluate the cognitive function of PD-MCI. Therefore, this study explored deficits in decision-making cognitive function in PD-MCI population, and mined novel digital biomarkers for recognizing early cognitive decline in PD-MCI through an independently designed maze decision-making digital assessment paradigm. This study included 30 healthy controls 37 PD with normal cognition (PD-NC) and 40 PD-MCI patients. Through difference comparison and stepwise regression analysis, two digital decision-making biomarkers, total decision time and performance average acceleration, were screened, and their joint area under curve for the ability to discriminate between PD-MCI and PD-NC was 0.909, and for the ability to discriminate between PD-MCI and NC was 0.942. In addition, it was found that maze digital decision-making biomarkers had greater early warning efficacy in men than in women. Unlike traditional methods, this study used digital dynamic assessment to reveal possible decision-making cognitive deficits in the PD-MCI populations, which provides new ideas for effective screening for PD-MCI.

Polypharmacy and anticholinergic burden as risk factors for postoperative delirium in surgical medicine

PURPOSE

Polypharmacy is a widespread phenomenon in older patients. In particular, the anticholinergic burden of medication is an important risk factor for delirium due to age-related changes in the cholinergic system.

METHODS

Preoperative medication, including the calculation of the anticholinergic burden (ACB), was recorded in a prospective study (421 patients) to identify potential risks associated with medication intake. Postoperative delirium screening was carried out daily.

RESULTS

The study included 199 women (47.3%) and 222 men (52.7%) aged 80.8 ± 6.7 years and 78.8 ± 6.2 years, respectively. Antidepressants odds ratio (OR) 3.16 (95% confidence interval. CI, 1.51-6.64), antidiabetic drugs OR 2.53 (95% CI 1.27-5.03), neuroleptics OR 3.52 (95% CI 1.70-7.28) and Parkinson medication OR 5.88 (95% CI 1.95-17.7) showed a significantly higher risk for delirium. The ACB score revealed an anticholinergic burden in 43 patients (10.4%). The delirium rate was 25.6% (n = 11) and 11.0% (n = 40) had no anticholinergic burden. A significant correlation can be demonstrated with χ2(1) = 7.52, p = 0.006, Cramer's V = 0.136. There was a 2.79-fold higher risk of delirium (OR 2.79, 95% CI 1.31-5.97).

CONCLUSION

The standardized recording of medication is essential, especially when identifying patients at risk of suffering from delirium. The use of the ACB score to assess the anticholinergic burden is a simple and reliable screening tool and should be part of a preoperative geriatric assessment.

Noninvasive Therapies: A Forthcoming Approach to Parkinson's Treatment

In this review, we have discussed the invasive and non-invasive treatment options for Parkinson's Disease (PD) following their safety, specificity, and reliability. Initially, this study has highlighted the invasive treatment options and the side effects they possess. A deep understanding of L-Dopa treatment, as oral or infusion, and the use of dopamine agonists has indicated that there is a need to acquire an alternative treatment for PD. The combined therapy with L-Dopa has been proven to affect PD, but with some limitations, such as mild to chronic side effects, with particular requirements of age and health of the patient and a large amount of expenditure. In the discussion of noninvasive methods to treat PD, we have found that this approach is comparatively slow and requires repetitive sessions, but is safe, effective, and reliable at any stage of PD. Electroconvulsive therapy has revealed its effectiveness in various neurological diseases, including PD. Transcranial current stimulation (direct or alternative) has already been shown to have an alleviative response to PD symptoms. Transcranial magnetic stimulations and other strategies of using the magnetic field for potential treatment options for PD need to be explored further imminently.

Neuropsychiatric drug development: Perspectives on the current landscape, opportunities and potential future directions

Mental health represents a major challenge to our societies. One key difficulty associated with neuropsychiatric drug development is the lack of connection between the underlying biology and the disease. Nevertheless, there is growing optimism in this field with recent drug approvals (the first in decades) and renewed interest from pharmaceutical companies and investors. Here we review some of the most promising drug discovery and development endeavors currently deployed by industry. We also present elements illustrating the renewed interest from key stakeholders in neuropsychiatric drug development and provide potential future directions in this field.

The role of the gut microbiota and the nicotinate/nicotinamide pathway in rotenone-induced neurotoxicity

Rotenone is a natural compound from plants. It is widely used in pesticides because of highly toxic to insects and fish. However, lots of research has reported that rotenone has neurotoxic effects in humans. It is confirmed there is a correlation between rotenone exposure and Parkinson's disease (PD). Therefore, the role of gut microbiota and related metabolic pathways was investigated in rotenone-induced neurotoxicity. The results showed that the abundance of gut microbiota changed significantly. The differential metabolites were enriched in the nicotinate and nicotinamide metabolism pathways, which had the greatest impact on the entire metabolic system. The contents of acetic acid and butyric acid in intestinal tissues decreased significantly. Additionally, Interleukin-6 (IL-6), Tumor necrosis factor alpha (TNF-α) and vasoactive intestinal peptide (VIP) were significantly up-regulated, while gastrin (GAS) and Ghrelin were significantly down-regulated. Expression of intestinal tight junction protein was significantly reduced. Moreover, nicotinamide adenine dinucleotide (NAD+), a the product of the nicotinate/nicotinamide pathways, decreased significantly. And the expression levels of nicotinamide phosphoribosyl transferase (NAMPT) and Solute Carrier Family 25 Member 51 (SLC25A51) also reduced significantly. Therefore, gut microbiota was influenced obviously in rats exposed to rotenone, leading to a decrease of acetic acid and butyric acid contents, which might in turn affect the change of intestinal barrier permeability and induce inflammatory reactions. Meanwhile, the nicotinate/nicotinamide metabolic pathways might play an important role in rats exposed to rotenone.

Psychiatric Disorders and Cognitive Fluctuations in Parkinson's Disease: Changing Approaches in the First Decades of the 21st Century

Parkinson's Disease (PD) is a multifaceted neurodegenerative disorder characterized, in addition to the well-recognized motor disturbances, by a complex interplay between cognitive and psychiatric manifestations. We dissect the complex landscape of PD-related psychiatric symptoms, taking into account the impact of functional neurological disorders, somatic delusions, impulse control disorders, and conditions within the bipolar spectrum. The newer entities of somatoform and functional neurological disorders, as well as preexisting bipolar spectrum disorders, are analyzed in detail. Moreover, we emphasize the need for a holistic understanding of PD, wherein the cognitive and psychiatric dimensions are valued alongside motor symptoms. Such an approach aims to facilitate early detection and personalized interventions, and enhance the overall quality of life for individuals suffering from this neurodegenerative disorder.

Cholinergic Basal Forebrain Integrity and Cognition in Parkinson's Disease: A Reappraisal of Magnetic Resonance Imaging Evidence

Cognitive impairment is a well-recognized and debilitating symptom of Parkinson's disease (PD). Degradation in the cortical cholinergic system is thought to be a key contributor. Both postmortem and in vivo cholinergic positron emission tomography (PET) studies have provided valuable evidence of cholinergic system changes in PD, which are pronounced in PD dementia (PDD). A growing body of literature has employed magnetic resonance imaging (MRI), a noninvasive, more cost-effective alternative to PET, to examine cholinergic system structural changes in PD. This review provides a comprehensive discussion of the methodologies and findings of studies that have focused on the relationship between cholinergic basal forebrain (cBF) integrity, based on T1- and diffusion-weighted MRI, and cognitive function in PD. Nucleus basalis of Meynert (Ch4) volume has been consistently reduced in cognitively impaired PD samples and has shown potential utility as a prognostic indicator for future cognitive decline. However, the extent of structural changes in Ch4, especially in early stages of cognitive decline in PD, remains unclear. In addition, evidence for structural change in anterior cBF regions in PD has not been well established. This review underscores the importance of continued cross-sectional and longitudinal research to elucidate the role of cholinergic dysfunction in the cognitive manifestations of PD. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Purinergic-associated immune responses in neurodegenerative diseases

The chronic activation of immune cells can participate in the development of pathological conditions such as neurodegenerative diseases including Alzheimer's disease (AD), Multiple Sclerosis (MS), Parkinson's disease (PD), Huntington's disease (HD) and Amyotrophic Lateral Sclerosis (ALS). In recent years, compelling evidence indicates that purinergic signaling plays a key role in neuro-immune cell functions. The extracellular release of adenosine 5'-triphosphate (ATP), and its breakdown products (ADP and adenosine) provide the versatile basis for complex purinergic signaling through the activation of several families of receptors. G-protein coupled adenosine A2A receptors, ionotropic P2X and G-protein coupled P2Y receptors for ATP and other nucleotides are abundant and widely distributed in neurons, microglia, and astrocytes of the central nervous system as well as in peripheral immune cells. These receptors are strongly linked to inflammation, with a functional interplay that may influence the intricate purinergic signaling involved in inflammatory responses. In the present review, we examine the roles of the purinergic receptors in neuro-immune cell functions with particular emphasis on A2AR, P2X4 and P2X7 and their possible relevance to specific neurodegenerative disorders. Understanding the molecular mechanisms governing purinergic receptor interaction will be crucial for advancing the development of effective immunotherapies targeting neurodegenerative diseases.

Neuropsychiatric symptoms in Parkinson's disease: review of data from the Arab world

Neuropsychiatric symptoms in Parkinson's disease (PD) are common, underrecognized, and impact patients' quality of life. Research around this topic is scarce in the Arab world. The aim of this comprehensive narrative review was to examine available evidence and discusses its strengths and limitations. The PubMed and Embase databases were searched using relevant keywords for studies published between 2000 and 2023. A total of 10 epidemiological and three assessment tool validation studies of neuropsychiatric symptoms in PD, conducted in the 22 Arab countries, were included. Only four Arab countries contributed to the 10 epidemiological studies found. Egypt provided the largest number of patients. Prevalence rates of neuropsychiatric symptoms in PD were heterogenous. Three studies relied on the Non-Motor Symptom Scale to estimate prevalence. Three studies used validated screening tools for dementia. Five studies used specific screening tools for depression, while two used the Diagnostic and Statistical Manual of mental disorders, fourth edition (DSM-IV) diagnostic criteria for depression. No appropriate and validated tool is available to assess for apathy. The generalizability of the findings is limited and recommendations for future studies are provided.

From prodromal stages to clinical trials: The promise of digital speech biomarkers in Parkinson's disease

Speech impairment is a common and disabling symptom in Parkinson's disease (PD), affecting communication and quality of life. Advances in digital speech processing and artificial intelligence have revolutionized objective speech analysis. Given the complex nature of speech impairment, acoustic speech analysis offers unique biomarkers for neuroprotective treatments from the prodromal stages of PD. Digital speech biomarkers can monitor levodopa-induced motor complications, detect the effects of deep brain stimulation, and provide feedback for behavioral speech therapy. This review updates the mechanisms underlying speech impairment, the impact of speech phenotypes, and the effects of interventions on speech. We evaluate the strengths, potential weaknesses, and suitability of promising digital speech biomarkers in PD for capturing disease progression and treatment efficacy. Additionally, we explore the translational potential of PD speech biomarkers to other neuropsychiatric diseases, offering insights into motion, cognition, and emotion. Finally, we highlight knowledge gaps and suggest directions for future research to enhance the use of quantitative speech measures in disease-modifying clinical trials. The findings demonstrate that one year is sufficient to detect disease progression in early PD through speech biomarkers. Voice quality, pitch, loudness, and articulation measures appear to capture the efficacy of treatment interventions most effectively. Certain speech features, such as loudness and articulation rate, behave oppositely in different neurological diseases, offering valuable insights for differential diagnosis. In conclusion, this review highlights speech as a biomarker in tracking disease progression, especially in the prodromal stages of PD, and calls for further longitudinal studies to establish its efficacy across diverse populations.

Imaging of impulse control disorders in Parkinson's disease

Impulse control disorders (ICD) are frequent and cumbersome behavioral disorders in patients with Parkinson's disease (PD). Understanding their pathophysiological underpinnings is crucial. Molecular imaging using positron emission tomography (PET) and single-photon emission computed tomography (SPECT) clearly indicates preexisting vulnerability and abnormal sensitization of the pre- and postsynaptic dopaminergic system. Functional magnetic resonance imaging (fMRI) studies reveal abnormal connectivity within the reward system involving the ventral striatum and orbitofrontal cortex. These alterations pinpoint the dysfunction of reinforcement learning in ICD, which is biased toward the overvaluation of reward and underestimation of risk, and the deficit in inhibitory control mechanisms related to abnormal connectivity within and between the limbic and the associative and motor networks.

Associations of motor and neuropsychiatric symptoms with comorbidities in prodromal Parkinson's disease

Objective

To investigate the associations between comorbidities and multimorbidity patterns with motor and neuropsychiatric symptoms in patients with Parkinson's disease (PD) in prodromal PD.

Methods

Multimorbidity is defined as the coexistence of two or more long-term conditions (LTCs) (also known as multiple comorbidities). A total of 921 participants without PD were included in the Parkinson's Progression Markers Initiative (PPMI) database and were categorized according to the LTC count. Participants were evaluated on motor and psychiatric symptoms. Pearson correlation to examine relationship of comorbidities and target symptoms. The baseline population was analyzed using Multiple linear regression model, while mixed effects model was utilized for longitudinal analysis. Fuzzy C-means clustering analysis was conducted to identify comorbidity patterns, followed by multiple linear regression for further analysis.

Results

At baseline, a higher LTC count was significantly correlated with more severe motor (MDS-UPDRS I, II, ADL, all P < 0.05) and neuropsychiatric symptoms (QUIP, P < 0.001). Three multimorbidity patterns were identified. Among them, the cardiometabolic multimorbidity pattern (CAR) had the most significant correlation with the aforementioned symptoms. Our longitudinal analysis indicated that an increase in the LTC count was associated with the exacerbation of motor and neuropsychiatric symptoms.

Conclusion

Comorbidities were cross-sectionally and longitudinally associated with the motor and neuropsychiatric symptoms of patients with prodromal PD. Among the three multimorbidity patterns, CAR posed the highest threat to the risk of more severe motor and neuropsychiatric symptoms.

Gene Therapy for Parkinson's Disease Using Midbrain Developmental Genes to Regulate Dopaminergic Neuronal Maintenance

Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder. It is characterized by the progressive loss of dopaminergic (DAnergic) neurons in the substantia nigra and decreased dopamine (DA) levels, which lead to both motor and non-motor symptoms. Conventional PD treatments aim to alleviate symptoms, but do not delay disease progression. PD gene therapy offers a promising approach to improving current treatments, with the potential to alleviate significant PD symptoms and cause fewer adverse effects than conventional therapies. DA replacement approaches and DA enzyme expression do not slow disease progression. However, DA replacement gene therapies, such as adeno-associated virus (AAV)-glutamic acid decarboxylase (GAD) and L-amino acid decarboxylase (AADC) gene therapies, which increase DA transmitter levels, have been demonstrated to be safe and efficient in early-phase clinical trials. Disease-modifying strategies, which aim to slow disease progression, appear to be potent. These include therapies targeting downstream pathways, neurotrophic factors, and midbrain DAnergic neuronal factors, all of which have shown potential in preclinical and clinical trials. These approaches focus on maintaining the integrity of DAnergic neurons, not just targeting the DA transmitter level itself. In particular, critical midbrain developmental and maintenance factors, such as Nurr1 and Foxa2, can interact synergistically with neighboring glia, in a paracrine mode of action, to protect DAnergic neurons against various toxic factors. Similar outcomes could be achieved by targeting both DAnergic neurons and glial cells with other candidate gene therapies, but in-depth research is needed. Neurotrophic factors, such as neurturin, the glial-cell-line-derived neurotrophic factor (GDNF), the brain-derived neurotrophic factor (BDNF), and the vascular endothelial growth factor (VEGF), are also being investigated for their potential to support DAnergic neuron survival. Additionally, gene therapies targeting key downstream pathways, such as the autophagy-lysosome pathway, mitochondrial function, and endoplasmic reticulum (ER) stress, offer promising avenues. Gene editing and delivery techniques continue to evolve, presenting new opportunities to develop effective gene therapies for PD.

The effects of chemogenetic targeting of serotonin-projecting pathways on L-DOPA-induced dyskinesia and psychosis in a bilateral rat model of Parkinson's disease

Introduction

Parkinson's disease (PD) is commonly characterized by severe dopamine (DA) depletion within the substantia nigra (SN) leading to a myriad of motor and non-motor symptoms. One underappreciated and prevalent non-motor symptom, Parkinson's disease-associated psychosis (PDAP), significantly erodes patient and caregiver quality of life yet remains vastly understudied. While the gold standard pharmacotherapy for motor symptoms Levodopa (LD) is initially highly effective, it can lead to motor fluctuations like LD-induced dyskinesia (LID) and non-motor fluctuations such as intermittent PDAP. One source of these fluctuations could be the serotonergic raphe nuclei and their projections. Serotonin (5-HT) neurons possess the machinery necessary to convert and release DA from exogenous LD. In DA-depleted brain regions these 5-HT projections can act as surrogates to the DA system initially compensating but chronically leading to aberrant neuroplasticity which has been linked to LID and may also contribute to non-motor fluctuations. In support, recent work from our lab established a positive relationship between LID and PDAP in parkinsonian rats. Therefore, it was hypothesized that normalizing 5-HT forebrain input would reduce the co-expression of LID and PDAP.

Methods

To do so, we expressed 5-HT projection specific inhibitory designer receptor exclusively activated by designer drugs (DREADDs) using Cre-dependent AAV9-hM4di in tryptophan hydroxylase 2 (TPH2)-Cre bilaterally 6-OHDA-lesioned rats. Thereafter we used the designer drug Compound 21 to selectively inhibit 5-HT raphe projections during LD treatment to modulate the expression of PDAP, assayed by prepulse inhibition (PPI) and LID, quantified by the abnormal involuntary movements (AIMs) test.

Results

Our results suggest that chemogenetic inhibition of 5-HT raphe-projecting cells significantly reduces LID without affecting stepping ability or established sensorimotor gating deficits.

Discussion

Overall, this study provides further evidence for the complex influence of 5-HT raphe-projecting neurons on LD's neurobehavioral effects.

Polygonatum sibiricum polysaccharides: A promising strategy in the treatment of neurodegenerative disease

Neurodegenerative diseases (NDDs), as a neurological disorder characterised by neuronal degeneration and death, are a serious threat to human health and have long attracted attention due to their complex pathogenesis and the ineffectiveness of therapeutic drugs. Existing studies have shown that Polygonatum Sibiricum polysaccharides (PSP) have immunoregulatory, antioxidant, anti-inflammatory and other pharmacological effects, and their neuroprotective effects have been demonstrated in several scientific studies. This paper reviews the main pharmacological effects and mechanisms of PSP in the protection and treatment of NDDs, to provide a reference for the clinical application and basic research of PSP in NDDs.

Altered gait speed and brain network connectivity in Parkinson's disease

Slow gait speed and disrupted brain network connectivity are common in patients with Parkinson's disease (PD). This study aimed to clarify the relationship between gait speed and clinical characteristics in PD, and explore the underlying brain network mechanisms. Forty-two PD patients and 20 healthy controls (HC) were recruited. Statistical independent component analysis and correlation analysis were employed to investigate underlying neural mechanisms and relationships. PD patients exhibited significantly slower gait speed, which showed a significant negative correlation with postural instability and gait disturbance scores. Network connectivity analysis revealed decreased intranetwork functional connectivity (FC) within visual network (VN) and cerebellum network (CN), but increased internetwork FC between CN and both sensorimotor network (SMN) and frontoparietal network (FPN) in PD patients compared to HC. The slow gait speed PD subgroup demonstrated increased intranetwork FC within SMN and VN, along with decreased FC between VN and both FPN and default mode network. Correlation analyses revealed negative correlation between gait speed and FC of CN and positive correlation to FC of CN-SMN. Our study identified relationships between gait speed and clinical characteristics, and corresponding network connectivity alterations in PD patients, providing insights into the neural mechanisms underlying gait impairments in PD.

Causal association between Parkinson's disease and cancer: a bidirectional Mendelian randomization study

Background

Previous observational research has indicated a correlation between Parkinson's disease (PD) and multiple cancers; but the causality remains unclear. Thus, we utilized Mendelian randomization (MR) analysis to explore the potential causal link between PD and various cancers.

Methods

We conducted a bidirectional two-sample Mendelian randomization (TSMR) of genetic variants associated with PD and 14 types of cancers. Summary statistics on PD and 14 types of cancers were obtained from the International Parkinson's Disease Genomics Consortium and the study by Sakaue et al. The primary method employed was inverse variance weighted (IVW), complemented by multiple sensitivity analyses to evaluate heterogeneity and pleiotropy. The false discovery rate (FDR) was employed to control the false positive rate of multiple hypothesis testing.

Results

Following rigorous sensitivity analyses and corrections, our findings revealed suggestive associations between PD and certain cancers. We observed that PD decreases the risk of gastric cancer and colorectal cancer (OR = 0.936, 95% CI = 0.881-0.995, p = 0.034, P FDR = 0.239; OR = 0.955, 95% CI = 0.912-0.999, p = 0.046, P FDR = 0.215), while increasing the risk of breast cancer (OR = 1.043, 95% CI = 1.004-1.084, p = 0.029, P FDR = 0.402). Notably, we found no evidence supporting a reverse causal relationship. Additionally, in the reverse pathway, skin cancer demonstrated a suggestive causal relationship with PD (OR = 0.913, 95% CI = 0.857-0.973, p = 0.005, P FDR = 0.066).

Conclusion

Our MR analysis provides evidence supporting unidirectional suggestive causal relationships between PD and certain cancers. These findings enrich our comprehension of the intricate interplay between PD and cancer, warranting further investigation into the underlying biological mechanisms.

Deciphering the effects of STN DBS on neuropsychiatric fluctuations in Parkinson's disease

The impact of subthalamic nucleus (STN) deep brain stimulation (DBS) on neuropsychiatric fluctuations in Parkinson´s disease (PD) remains unclear. The Neuropsychiatric Fluctuations Scale (NFS) can help to fill this gap, directly measuring fluctuations between the OFF- and ON-medication conditions. The NFS provides NFS-plus (hyperdopaminergic) and NFS-minus (hypodopaminergic) sub-scores. Based on these, the NFS global scores express the overall magnitude of neuropsychiatric symptoms in both the OFF- and ON-medication states. The total fluctuation score (TFS) represents the difference between ON- vs. OFF-medication NFS global scores, thus assessing fluctuations amplitude. The NFS was used to evaluate changes in neuropsychiatric fluctuations between the OFF- and ON-medication conditions before and 1-year after bilateral STN-DBS in 45 PD patients (32 males; mean age, 61.3 ± 7.2 years; PD duration, 10.2 ± 3.0 years). After surgery, the amplitude of neuropsychiatric fluctuations was significantly reduced (p < 0.001), confirming the efficacy of STN-DBS on these symptoms.

Mitochondrial Dysfunction in Parkinson's Disease: A Contribution to Cognitive Impairment?

Among the non-motor symptoms associated with Parkinson's disease (PD), cognitive impairment is one of the most common and disabling. It can occur either early or late during the disease, and it is heterogeneous in terms of its clinical manifestations, such as Subjective Cognitive Dysfunction (SCD), Mild Cognitive Impairment (MCI), and Parkinson's Disease Dementia (PDD). The aim of the present review is to delve deeper into the molecular mechanisms underlying cognitive decline in PD. This is extremely important to delineate the guidelines for the differential diagnosis and prognosis of the dysfunction, to identify the molecular and neuronal mechanisms involved, and to plan therapeutic strategies that can halt cognitive impairment progression. Specifically, the present review will discuss the pathogenetic mechanisms involved in the progression of cognitive impairment in PD, with attention to mitochondria and their contribution to synaptic dysfunction and neuronal deterioration in the brain regions responsible for non-motor manifestations of the disease.

Brain-Region-Specific Differences in Protein Citrullination/Deimination in a Pre-Motor Parkinson's Disease Rat Model

The detection of early molecular mechanisms and potential biomarkers in Parkinson's disease (PD) remains a challenge. Recent research has pointed to novel roles for post-translational citrullination/deimination caused by peptidylarginine deiminases (PADs), a family of calcium-activated enzymes, in the early stages of the disease. The current study assessed brain-region-specific citrullinated protein targets and their associated protein-protein interaction networks alongside PAD isozymes in the 6-hydroxydopamine (6-OHDA) induced rat model of pre-motor PD. Six brain regions (cortex, hippocampus, striatum, midbrain, cerebellum and olfactory bulb) were compared between controls/shams and the pre-motor PD model. For all brain regions, there was a significant difference in citrullinated protein IDs between the PD model and the controls. Citrullinated protein hits were most abundant in cortex and hippocampus, followed by cerebellum, midbrain, olfactory bulb and striatum. Citrullinome-associated pathway enrichment analysis showed correspondingly considerable differences between the six brain regions; some were overlapping for controls and PD, some were identified for the PD model only, and some were identified in control brains only. The KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways identified in PD brains only were associated with neurological, metabolic, immune and hormonal functions and included the following: "Axon guidance"; "Spinocerebellar ataxia"; "Hippo signalling pathway"; "NOD-like receptor signalling pathway"; "Phosphatidylinositol signalling system"; "Rap1 signalling pathway"; "Platelet activation"; "Yersinia infection"; "Fc gamma R-mediated phagocytosis"; "Human cytomegalovirus infection"; "Inositol phosphate metabolism"; "Thyroid hormone signalling pathway"; "Progesterone-mediated oocyte maturation"; "Oocyte meiosis"; and "Choline metabolism in cancer". Some brain-region-specific differences were furthermore observed for the five PAD isozymes (PADs 1, 2, 3, 4 and 6), with most changes in PAD 2, 3 and 4 when comparing control and PD brain regions. Our findings indicate that PAD-mediated protein citrullination plays roles in metabolic, immune, cell signalling and neurodegenerative disease-related pathways across brain regions in early pre-motor stages of PD, highlighting PADs as targets for future therapeutic avenues.

Treatment of Parkinson's Disease Psychosis-A Systematic Review and Multi-Methods Approach

OBJECTIVES

Parkinson's disease psychosis (PDP) is a prevalent non-motor symptom associated with Parkinson's disease. The treatment options for PDP are limited, and its pharmacological management remains ambiguous. This study aimed to evaluate the existing evidence in relation to clinical practice.

METHODS

This multi-methods study consisted of a systematic review of reviews, adhering to the PRISMA guidelines. The review was registered with PROSPERO. Following data extraction and assessment using the AMSTAR 2 tool, a narrative synthesis was performed. In the second phase of the study, a questionnaire was developed, validated, piloted, and distributed to the heads of specialized PD clinics in Germany and Austria.

RESULTS

The search resulted in the inclusion of eleven reviews. The quality of eight of these reviews was rated as high (n = 7) or moderate (n = 1). The reviews indicated that clozapine and pimavanserin demonstrated the highest efficacy and tolerability. Other antipsychotic medications either failed to alleviate PDP symptoms or resulted in distinct motor complications. The survey findings also favored clozapine for its efficacy in managing PDP and improving quality of life, although quetiapine was regarded as effective and pimavanserin was not available. Clinicians reported initiating antipsychotic treatment at various stages of PDP, with a tendency to reduce the dosage or discontinue D2 agonists or anticholinergics.

CONCLUSIONS

The reviewed literature and the survey results consistently favored clozapine for its efficacy and tolerability in treating PDP. It may be considered the first-line treatment, with pimavanserin as an alternative option.

Progress of non‐motor symptoms in early‐onset Parkinson's disease

Parkinson's disease (PD) is a common degenerative disease of the central nervous system that is characterized by movement disorders and non‐motor symptoms (NMSs). The associated NMSs primarily include neuropsychiatric symptoms, autonomic dysfunction, sleep‐wake disorders, pain, fatigue, and hyposmia. These NMSs can occur at any stage of PD, especially before the onset of motor symptoms, and may affect a patient's quality of life more than motor symptoms. Although PD is most commonly diagnosed in people over 65 years, some patients exhibit symptom onset before the age of 50, which is clinically known as early‐onset Parkinson's disease (EOPD). The high heterogeneity and incidence of EOPD‐associated NMSs can lead to the misdiagnosis of EOPD as other neurodegenerative diseases. In this review, we discuss the research progress related to NMSs in patients with EOPD, focusing on neuropsychiatric disorders, autonomic dysfunction, sleep disorders, and sensory impairment, and outline the association of NMSs with different genotypic alterations, with the aim of providing assistance in the clinical management of patients.

Ganoderic acid A mitigates dopaminergic neuron ferroptosis via inhibiting NCOA4-mediated ferritinophagy in Parkinson's disease mice

ETHNOPHARMACOLOGICAL RELEVANCE

Ganoderma lucidum, a renowned tonic traditional Chinese medicine, is widely recognized for the exceptional activity in soothing nerves and nourishing the brain. It has been extensively employed to alleviate various neurological disorders, notably Parkinson's disease (PD).

AIM OF THE STUDY

To appraise the antiparkinsonian effect of GAA, the main bioactive constituent of G. lucidum, and clarify the molecular mechanism through the perspective of ferritinophagy-mediated dopaminergic neuron ferroptosis.

MATERIALS AND METHODS

PD mouse and cell models were established using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and 1-methyl-4-phenylpyridinium (MPP+), respectively. Cell viability, behavioral tests and immunofluorescence analysis were performed to evaluate the neurotoxicity, motor dysfunction and dopaminergic loss, respectively. Biochemical assay kits were used to determine the levels of iron, lipid reactive oxygen species (ROS), malondialdehyde (MDA), total ROS and glutathione (GSH). Western blot and immunofluorescence were applied to detect the expressions of nuclear receptor co-activator 4 (NCOA4), ferritin heavy chain 1 (FTH1), p62 and LC3B. Additionally, NCOA4-overexpressing plasmid vector was constructed to verify the inhibitory effect of GAA on the neurotoxicity and ferroptosis-related parameters in PD models.

RESULTS

GAA significantly mitigated MPP+/MPTP-induced neurotoxicity, motor dysfunction and dopaminergic neuron loss (p＜0.01 or p＜0.05). In contrast to MPP+/MPTP treatment, GAA treatment decreased the levels of iron, MDA, lipid and total ROS, while increasing the GSH level. GAA also reduced the levels of NCOA4 and LC3B, and enhanced the expressions of FTH1 and p62 in PD models (p＜0.01 or p＜0.05). However, the protective effect of GAA against the neurotoxicity, NCOA4-mediated ferritinophagy and ferroptosis in PD model was abolished by the overexpression of NCOA4 (p＜0.01).

CONCLUSION

GAA exerted a protective effect on PD, and this effect was achieved by suppressing dopaminergic neuron ferroptosis through the inhibition of NCOA4-mediated ferritinophagy.

Cognitive behavioral therapy approaches to the improvement of mental health in Parkinson's disease patients: a systematic review and meta-analysis

BACKGROUND

Non-motor symptoms (NMS) such as impaired cognition, anxiety, and depression can have a strong adverse effect on the quality of life (QoL) of Parkinson's disease (PD) patients. The clinical application of cognitive behavioral therapy (CBT) offers an opportunity to improve cognitive function, mental health, and overall QoL for these patients.

OBJECTIVE

CBT is frequently applied as a treatment option aimed at benefiting the mental health of PD patients, but the relative utility of CBT in this patient population has yet to be rigorously assessed. The present review was thus conducted with the goal of examining the relative safety and efficacy of CBT as a treatment option for PD patients suffering from cognitive impairment, anxiety, and depression, with a particular focus on the impact of CBT on PD patient QoL.

METHODS

The PubMed, Embase, Medline, and Cochrane Library databases were searched for all studies published from their inception to present using keywords including "cognitive behavioral therapy" and "Parkinson's disease". Two reviewers independently screened these published studies and extracted relevant data from studies that met with defined inclusion/exclusion criteria, in addition to assessing the risk of bias. Those randomized controlled trials (RCTs) assessing the impact of CBT on older PD patients were eligible for study inclusion. In total, 22 articles incorporating 1,053 patients were included in this meta-analysis. Study quality was examined as per the Cochrane risk of bias framework. Heterogeneity and associated outcomes were assessed based on mean difference (MD), I2, and 95% confidence interval (95%CI) values.

RESULTS

In total, 22 RCTs were ultimately found to be eligible for inclusion in the present meta-analysis. The results of this meta-analysis indicated that CBT significantly impacted cognition as compared to other treatment options (including placebo treatment, clinical monitoring, clinic-based treatment, psychoeducation, physical activity training, health enhancement) (I2 = 49%, MD = 0.23, 95%CI: 0.03-0.44, P = 0.03). CBT was also associated with significant improvements in PD patient QoL (I2 = 0%, MD = 3.45, 95%CI: 1.13-5.57, P = 0.04), anxiety symptoms (I2 = 57%, MD = -2.01, 95%CI: -4.01-0.01, P = 0.05), and depression symptoms (I2 = 74%, MD = -3.94, 95%CI: -6.47 to -1.42, P = 0.04).

CONCLUSIONS

These results reveal that CBT can have beneficial effects on PD patient cognitive status and QoL. Notably, CBT represents an effective option for treating NMS such as anxiety and depression in PD patients. These results offer strong evidence in favor of applying CBT as a means of enhancing the mental health, cognition, and QoL of individuals with PD. However, additional high-quality large-scale studies will be essential to confirm and expand upon these results.

Primary cilia in Parkinson's disease: summative roles in signaling pathways, genes, defective mitochondrial function, and substantia nigra dopaminergic neurons

Primary cilia (PC) are microtubules-based, independent antennal-like sensory organelles, that are seen in most vertebrate cells of different types, including astrocytes and neurons. They send signals to cells to control many physiological and cellular processes by detecting changes in the extracellular environment. Parkinson's disease (PD), a neurodegenerative disease that progresses over time, is primarily caused by a gradual degradation of the dopaminergic pathway in the striatum nigra, which results in a large loss of neurons in the substantia nigra compact (SNpc) and a depletion of dopamine (DA). PD samples have abnormalities in the structure and function of PC. The alterations contribute to the cause, development, and recovery of PD via influencing signaling pathways (SHH, Wnt, Notch-1, α-syn, and TGFβ), genes (MYH10 and LRRK2), defective mitochondrial function, and substantia nigra dopaminergic neurons. Thus, restoring the normal structure and physiological function of PC and neurons in the brain are effective treatment for PD. This review summarizes the function of PC in neurodegenerative diseases and explores the pathological mechanisms caused by PC alterations in PD, in order to provide references and ideas for future research.

Neuroanatomical and prognostic associations of depression in Parkinson's disease

BACKGROUND

Depression is reported as a risk factor, prodromal feature and late consequence of Parkinson's disease (PD). We aimed to evaluate the timing, neuroanatomy and prognostic implications of depression in PD.

METHODS

We used data from 434 023 participants from UK Biobank with 14.1 years of follow-up. Multivariable regression models established associations of depression with incident PD and regional brain volumes. Cox proportional hazards models assessed prognostic associations of depression in PD with incident dementia and all-cause mortality.

RESULTS

Of 2632 individuals with incident PD, 539 (20.5%) were diagnosed with depression at some point. Depression was associated with an increased risk of subsequent PD (risk ratio 1.53, 95% CI 1.37 to 1.72). Among incident PD cases, depression prevalence rose progressively from 10 years pre-PD diagnosis (OR 2.10, 95% CI 1.57 to 2.83) to 10 years postdiagnosis (OR 3.51, 95% CI 1.33 to 9.22). Depression severity in PD was associated with reduced grey matter volume in structures including the thalamus and amygdala. Depression prior to PD diagnosis increased risk of dementia (HR 1.47, 95% CI 1.05 to 2.07) and mortality (HR 1.30, 95% CI 1.07 to 1.58).

CONCLUSIONS

This large-scale prospective study demonstrated that depression prevalence increases from 10 years before PD diagnosis and is a marker of cortical and subcortical volume loss. Depression before PD diagnosis signals a worse prognosis in terms of dementia and mortality. This has clinical implications in stratifying people with poorer cognitive and prognostic trajectory in PD.

Effects of Smile Training on Gait Disturbance in Parkinson's Disease Patient with Neuropsychiatric Symptoms: A Single Case Design

OBJECTIVE

To verify the efficacy of smile training in improving gait disturbances in patients with Parkinson's disease (PD) exhibiting neuropsychiatric symptoms.

METHODS

A single-case BAB design with three intervention periods (B1, A1, and B2) was used. During periods B1 and B2, 10 min of smile training (facial muscles training and positive thinking training) was performed before the usual exercise therapy. During the A1 period, the participant received only the usual exercise therapy. During the intervention period, the Timed Up and Go test (TUG) was performed daily in both directions. Tau-U was calculated to determine the effect size of the TUG test time and the number of steps taken during each period. Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part III, Hospital Anxiety and Depression Scale (HADS), 10-meter walk at maximum speed, Berg Balance Scale, and Characterizing Freezing of Gait Questionnaire (C-FOGQ) were administered on the day before the start of the intervention and the last day of each period.

RESULTS

Comparisons of A1 to B2, TUG time, and the number of steps taken on both turns revealed large reductions (Tau-U ≥0.74, p <0.01). The 10-meter walk speed and MDS-UPDRS Part III bradykinesia scores improved, whereas the frequency of gait freezing on the C-FOGQ remained unchanged. The HADS scores did not show significant changes; however, the participant made more positive statements in his reflections.

CONCLUSION

Smile training may be an effective intervention for improving gait and other motor symptoms in patients with PD.

A systematic review of the factors associated with the psychological wellbeing of people with Parkinson's in the COVID-19 pandemic

PURPOSE

The lockdown and social distancing measures introduced as a result of the COVID-19 pandemic impacted the ability of people with Parkinson's to engage in normal health management practices. This led to documented reductions in psychological wellbeing. The aim of the present review was to identify factors associated with the psychological wellbeing of people with Parkinson's during the acute stage of the pandemic.

MATERIALS AND METHODS

Five academic databases (PsycINFO, MEDLINE, Embase, CINAHL, and Web of Science) were searched and 23 articles were identified using pre-defined inclusion and exclusion criteria. The findings are stratified by risk factor and analysed using a narrative synthesis.

RESULTS

Worsening of motor symptoms, poor motor-related daily living experiences and motor symptoms during "off time" (when symptom suppressing medication has worn off) as well as less physical activity emerged as the most consistent risk factors of worsened or poorer psychological wellbeing. A deviation from pre-pandemic risk factors was identified, with age and gender not identified as consistent risk factors.

CONCLUSIONS

The implications of this review are not limited to preparing for future pandemics but can also be applied to more common concerns with comparable contextual characteristics such as yearly flu outbreaks, social isolation, and economic uncertainty.

Current interventional model for movement in Parkinson's disease: network meta-analysis based on the improvement of motor ability

Aim

To identify optimally therapeutic exercise interventions for improving motor ability among patients with Parkinson's disease (PD), we conducted a network meta-analysis (NMA) of randomized controlled trials comparing different exercise regimens.

Methods

Relevant RCTs were retrieved by searching PubMed, Embase, Cochrane, Web of Science, CINAHL, CBM, China National Knowledge Infrastructure (CNKI), Wan fang, VIP, and other databases from inception to July 9, 2023 is available in English as the primary language. Exercise outcomes as measured by Movement Disorder Society- Unified Parkinson's Disease Rating Scale Part III (MDS-UPDRS-III) score change were evaluated and ranked using STATA software version 18.0. All included studies were assessed for methodological quality using the Cochrane Risk of Bias tool.

Results

The final NMA included 71 studies involving 3,732 participants, 87 intervention experiments, and 27distinct interventions. Although most exercise interventions showed some efficacy (reducing MDS-UPDRS-III score), cumulative ranking probability surface (SUCRA) values indicated that the best exercise interventions for motor function improvement were archery (95.6%), riding a bicycle (80.9%), and binary rhythm dance (80.8%).

Conclusion

An exercise intervention comprising archery, cycling, and(or) binary rhythm dance may yield superior improvements in motor function among patients with Parkinson's disease.

Clinically established early Parkinson's disease patients do not show impaired use of priors in conditions of perceptual uncertainty

The ability to use past learned experiences to guide decisions is an important component of adaptive behavior, especially when decision-making is performed under time pressure or when perceptual information is unreliable. Previous studies using visual discrimination tasks have shown that this prior-informed decision-making ability is impaired in Parkinson's disease (PD), but the mechanisms underlying this deficit and the precise impact of dopaminergic denervation within cortico-basal circuits remain unclear. To shed light on this problem, we evaluated prior-informed decision-making under various conditions of perceptual uncertainty in a sample of 13 clinically established early PD patients, and compared behavioral performance with healthy control (HC) subjects matched in age, sex and education. PD patients and HC subjects performed a random dot motion task in which they had to decide the net direction (leftward vs. rightward) of a field of moving dots and communicate their choices through manual button presses. We manipulated prior knowledge by modulating the probability of occurrence of leftward vs. rightward motion stimuli between blocks of trials, and by explicitly giving these probabilities to subjects at the beginning of each block. We further manipulated stimulus discriminability by varying the proportion of dots moving coherently in the signal direction and speed-accuracy instructions. PD patients used choice probabilities to guide perceptual decisions in both speed and accuracy conditions, and their performance did not significantly differ from that of HC subjects. An additional analysis of the data with the diffusion decision model confirmed this conclusion. These results suggest that the impaired use of priors during visual discrimination observed at more advanced stages of PD is independent of dopaminergic denervation, though additional studies with larger sample sizes are needed to more firmly establish this conclusion.

GALNT9 enrichment attenuates MPP+-induced cytotoxicity by ameliorating protein aggregations containing α-synuclein and mitochondrial dysfunction

BACKGROUND

GALNTs (UDP-GalNAc; polypeptide N-acetylgalactosaminyltransferases) initiate mucin-type O-GalNAc glycosylation by adding N-GalNAc to protein serine/threonine residues. Abnormalities in O-GalNAc glycosylation are involved in various disorders such as Parkinson's disease (PD), a neurodegenerative disorder. GALNT9 is potentially downregulated in PD patients.

METHODS

To determine whether GALNT9 enrichment ameliorates cytotoxicity related to PD-like variations, a pcDNA3.1-GALNT9 plasmid was constructed and transfected into SH-SY5Y cells to establish a GALNT9-overexpressing cell model.

RESULTS

Downregulation of GALNT9 and O-GalNAc glycosylation was confirmed in our animal and cellular models of PD-like variations. GALNT9 supplementation greatly attenuated cytotoxicity induced by MPP+ (1-Methyl-4-phenylpyridinium iodide) since it led to increased levels of tyrosine hydroxylase and dopamine, reduced rates of apoptosis, and significantly ameliorated MPP+-induced mitochondrial dysfunction by alleviating abnormal levels of mitochondrial membrane potential and reactive oxygen species. A long-lasting mPTP (mitochondrial permeability transition pores) opening and calcium efflux resulted in significantly lower activity in the cytochrome C-associated apoptotic pathway and mitophagy process, signifying that GALNT9 supplementation maintained neuronal cell health under MPP+ exposure. Additionally, it was found that glycans linked to proteins influenced the formation of protein aggregates containing α-synuclein, and GALNT9 supplement dramatically reduced such insoluble protein aggregations under MPP+ treatment. Glial GALNT9 predominantly appears under pathological conditions like PD-like variations.

CONCLUSIONS

GALNT9 enrichment improved cell survival, and glial GALNT9 potentially represents a pathogenic index for PD patients. This study provides insights into the development of therapeutic strategies for the treatment of PD.

Parkinson's disease motor intervention patterns: a network meta-analysis based on patient motor function

Background

Parkinson's disease is characterized by symptoms such as bradykinesia and rigidity, which worsen as the disease progresses, significantly impacting patients' independence and quality of life. This study utilizes a network meta-analysis approach to quantify information gathered from randomized controlled trials (RCTs) regarding motor interventions that effectively improve the motor function of Parkinson's disease patients, aiming to provide evidence for selecting appropriate exercise intervention strategies for patients.

Methods

A systematic search strategy for randomized controlled trials (RCTs) restricted to English was constructed based on multiple biomedical databases. Databases searched included PubMed, Embase, Cochrane, Web of Science, CINAHL, CBM, China National Knowledge Infrastructure (CNKI), Wan fang, VIP, etc., with searches conducted from inception to July 9, 2023. Two authors screened all studies, extracted data, and used frequency domain analysis methods. Network meta-analysis was performed using STATA software version 18.0 to compare and rank exercises that could effectively improve the motor function of Parkinson's disease patients (measured by indicators such as MDS-UPDRS-III, TUG, BBS, Mini-BES Test, 6MWT scores). Additionally, a series of analyses and evaluations were conducted, such as assessing the methodological quality of included studies using the Cochrane risk of bias tool.

Results

The network meta-analysis included a total of 111 studies involving 5,358 participants, 133 intervention experiments, and 31 intervention measures. Although most exercise interventions showed effectiveness, cumulative ranking curves under the surface (SUCRA) values showed that archery exercise significantly improved patients' MDS-UPDRS-III scores (SUCRA = 95.6%), significantly superior to routine care [standardized mean difference (SMD = 16.92, 95%CI = -28.97, -4.87)]. High-intensity and agility exercise (High strength and agility) referred to as high-intensity exercise or agility training or a combination of both, collectively termed as high-intensity agility training, significantly improved patients' completion time for the time-up-and-go test (SUCRA = 99.7%), (SMD = -7.88, 95%CI = -9.47, -6.28). Dance and Tai Chi exercises significantly improved patients' balance abilities: Mini-Balance Evaluation Systems Test (SUCRA = 77.9%), (SMD = 5.25, 95%CI = -0.42, 10.92) for dance intervention and Berg Balance Scale (SUCRA = 94.7%), (SMD = 11.22, 95%CI = 3.26, 19.18) for Tai Chi intervention. Dance also significantly improved patients' walking ability in the 6-min walk test (SUCRA = 80.5%), (SMD = 71.31, 95%CI = 13.77, 128.84).

Conclusion

Compared to other exercises, archery, dance, Tai Chi, and high-intensity agility exercises demonstrate superior efficacy in improving the motor function of Parkinson's disease patients.

A Patient-Centered Perspective on Changes in Personal Characteristics After Deep Brain Stimulation

Importance

Deep brain stimulation (DBS) results in improvements in motor function and quality of life in patients with Parkinson disease (PD), which might impact a patient's perception of valued personal characteristics. Prior studies investigating whether DBS causes unwanted changes to oneself or one's personality have methodological limitations that should be addressed.

Objective

To determine whether DBS is associated with changes in characteristics that patients with PD identify as personally meaningful.

Design, Setting, and Participants

This cohort study assessed changes in visual analog scale (VAS) ratings reflecting the extent to which patients with PD manifested individually identified personal characteristics before and 6 and 12 months after DBS at a large academic medical center from February 21, 2018, to December 9, 2021. The VAS findings were tailored to reflect the top 3 individually identified personal characteristics the patient most feared losing. The VASs were scored from 0 to 10, with 0 representing the least and 10 the most extreme manifestation of the trait. Change scores were examined at the individual level. Content analysis was used to code the qualitative data. Qualitative and quantitative analyses were performed from January 12, 2019 (initial qualitative coding), to December 15, 2023.

Exposure

Deep brain stimulation.

Main Outcomes and Measures

The primary outcome variable was the mean VAS score for the top 3 personal characteristics. The secondary outcome was the incidence of meaningful changes on the patients' top 3 characteristics at the individual level.

Results

Fifty-two of 54 dyads of patients with PD and their care partners (96.3%) were recruited from a consecutive series approved for DBS (36 patients [69.2%] were male and 45 care partners [86.5%] were female; mean [SD] age of patients, 61.98 [8.55] years). Two patients and 1 care partner were lost to follow-up. Increases in the mean VAS score (indicative of greater manifestation of [ie, positive changes in] specific characteristics) were apparent following DBS for ratings of both the patients (Wald χ2 = 16.104; P < .001) and care partners (Wald χ2 = 6.746; P < .001) over time. The slopes of the changes for both the patient and care partners were correlated, indicating agreement in observed changes over time. The individual level analyses indicated that scores for most patients and care partners remained the same or increased.

Conclusions and Relevance

In this cohort study, participants reported greater (more positive) manifestations of individually identified, valued characteristics after DBS. These findings may be relevant to informing decision-making for patients with advanced PD who are considering DBS.

Changes in slow-wave sleep characteristics in Parkinson's disease patients with mild-moderate depression

INTRODUCTION

Depression and sleep disturbances are commonly seen non-motor symptoms in patients with Parkinson's disease (PD). This study used polysomnography to examine the relationship between mild-moderate depression in PD and sleep characteristics, particularly slow wave activities (SWA).

METHODS

59 PD patients were split into two groups: nd-PD (n = 27) (patients with PD without depression) and d-PD (n = 32) (patients with PD with mild-moderate depression). Their clinical features, polysomnography parameters, and demographics were evaluated. Early and late sleep SWA spectrum densities and overnight SWA decline in different brain regions were particularly analyzed.

RESULTS

Non-rapid eye movement 3 (N3) sleep duration and percentage were greater in the d-PD group. N3 percentage was linked to depression (p = 0.014). During late sleep, higher SWA (0.5-4Hz) in the frontal and central regions, higher low-SWA (0.5-2Hz) in the whole brain, central and occipital regions, and higher high-SWA (2-4Hz) in the frontal region was observed in the d-PD group. During early sleep, there was also higher low-SWA (0.5-2Hz) in the occipital region. Patients in d-PD group exhibited reduced overnight high-SWA (2-4Hz) decline (Δhigh-SWA) in the whole brain and occipital regions. Δhigh-SWA(2-4Hz) in the occipital region were associated with depression (p = 0.049).

CONCLUSION

PD patients with mild-moderate depression have impaired slow wave sleep, exhibiting as increased N3 sleep, SWA, and reduced overnight SWA decline. This implies that synaptic strength reduction during sleep and impaired synaptic homeostasis regulation may be associated with depression in PD. Reduced overnight high-SWA decline in the occipital region may serve as a novel electrophysiological biomarker for indicating depression in PD.

The Care Needs of Patients With Cognitive Impairment in Late-Stage Parkinson's Disease

BACKGROUND

Cognitive impairment is common in Parkinson's disease (PD), but care needs and resource use for those with significant cognitive impairment are not well established.

METHODS

675 participants with PD from the international Care of Late-Stage Parkinsonism (CLaSP) study were grouped into those without (n = 333, 49%) and with cognitive impairment (MMSE < 24/30 or diagnosis of dementia or Mild Cognitive Impairment; n = 342, 51%) and their clinical features, care needs and healthcare utilisation compared. The relationship between cognition and healthcare consultations was investigated through logistic regression.

RESULTS

Cognitive impairment was associated with more motor and non-motor symptoms, less antiparkinsonian but higher rates of dementia and antipsychotic medication, worse subjective health status and greater caregiver burden. A considerable proportion did not have a pre-established cognitive diagnosis. Care needs were high across the whole sample but higher in the cognitive impairment group. Home care and care home use was higher in the cognitive impairment group. However, use of healthcare consultations was similar between the groups and significantly fewer participants with cognitive impairment had had recent PD Nurse consultations. Worse cognitive impairment was associated with lower frequency of recent PD nurse and multidisciplinary therapy consultation (physiotherapy, massage, occupational therapy, speech training and general nursing).

CONCLUSIONS

Those with cognitive impairment have more severe PD, higher care needs and greater social care utilisation than those with normal cognition, yet use of health care services is similar or less. Cognitive impairment appears to be a barrier to PD nurse and multidisciplinary therapy consultations. This challenges current models of care: alternative models of care may be required to serve this population.

PLAIN LANGUAGE SUMMARY

Parkinson's disease is a long-term progressive health condition. Over time, many people with Parkinson's develop problems with thinking and memory, called cognitive impairment. This can negatively impact the daily lives of the person with Parkinson's and their caregiver. It is also thought to be a barrier to accessing healthcare. How people with Parkinson's who have cognitive impairment use healthcare and detail of their care needs is not well known.We analysed data from a large sample of people with advanced Parkinson's from six European countries to investigate their symptoms, care needs and healthcare use. We compared those with cognitive impairment to (342 people) to those without cognitive impairment (333 people).We found that those with cognitive impairment had more severe Parkinson's across a range of symptoms compared to those without cognitive impairment. They also had more care needs, reported their health status to be worse, and their caregivers experienced greater strain from caring. Whilst use of other healthcare services was similar between the two groups, those with cognitive impairment were less likely to have recently seen a Parkinson's nurse than those without cognitive impairment. Further analysis showed an association between cognitive impairment and not having seen a Parkinson's nurse or therapist recently, taking psychiatric symptoms, functional disability and care home residence into account. Therapists included were physiotherapy, massage, occupational therapy, speech training and general nursing. These findings highlight unmet need. We suggest that healthcare should be more targeted to help this group of people, given their higher care needs.

How do HCN channels play a part in Alzheimer's and Parkinson's disease?

Neurodegenerative diseases like Alzheimer's and Parkinson's disease (AD and PD) are well-known, yet their underlying causes remain unclear. Recent studies have suggested that disruption of ion channels contribute to their pathogenesis. Among these channels, the hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, encoded by HCN1-4 genes, are of particular interest due to their role in generating hyperpolarization-activated current (Ih), which is crucial in various neural activities impacting memory and motor functions. A growing body of evidence underscores the pivotal role of HCN in Aβ generation, glial cell function, and ischemia-induced dementia; while HCN is expressed in various regions of the basal ganglia, modulating their functions and influencing motor disorders in PD; neuroinflammation triggered by microglial activation represents a shared pathological mechanism in both AD and PD, in which HCN also plays a significant part. This review delves into the neuronal functions governed by HCN, its roles in the aforementioned pathogenesis, its expression patterns in AD and PD, and discusses potential therapeutic drugs targeting HCN for the treatment of these diseases, aiming to offer a novel perspective and inspire future research endeavors.

Coadministration of 6-Shogaol and Levodopa Alleviates Parkinson's Disease-Related Pathology in Mice

Parkinson's disease (PD) is a neurodegenerative disease caused by the death of dopaminergic neurons in the nigrostriatal pathway, leading to motor and non-motor dysfunctions, such as depression, olfactory dysfunction, and memory impairment. Although levodopa (L-dopa) has been the gold standard PD treatment for decades, it only relieves motor symptoms and has no effect on non-motor symptoms or disease progression. Prior studies have reported that 6-shogaol, the active ingredient in ginger, exerts a protective effect on dopaminergic neurons by suppressing neuroinflammation in PD mice. This study investigated whether cotreatment with 6-shogaol and L-dopa could attenuate both motor and non-motor symptoms and dopaminergic neuronal damage. Both 6-shogaol (20 mg/kg) and L-dopa (80 mg/kg) were orally administered to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/probenecid- induced PD model mice for 26 days. The experimental results showed that L-dopa alleviated motor symptoms, but had no significant effect on non-motor symptoms, loss of dopaminergic neuron, or neuroinflammation. However, when mice were treated with 6-shogaol alone or in combination L-dopa, an amelioration in both motor and non-motor symptoms such as depression-like behavior, olfactory dysfunction and memory impairment was observed. Moreover, 6-shogaol-only or co-treatment with 6-shogaol and L-dopa protected dopaminergic neurons in the striatum and reduced neuroinflammation in the striatum and substantia nigra. Overall, these results suggest that 6-shogaol can effectively complement L-dopa by improving non-motor dysfunction and restoring dopaminergic neurons via suppressing neuroinflammation.

Shared and distinct cortical morphometric alterations in five neuropsychiatric symptoms of Parkinson's disease

Neuropsychiatric symptoms (including anxiety, depression, apathy, impulse-compulsive behaviors and hallucinations) are among the most common non-motor features of Parkinson's disease. Whether these symptoms should be considered as a direct consequence of the pathophysiologic mechanisms of Parkinson's disease is controversial. Morphometric similarity network analysis and epicenter mapping approach were performed on T1-weighted images of 505 patients with Parkinson's disease and 167 age- and sex-matched healthy participants from Parkinson's Progression Markers Initiative database to reveal the commonalities and specificities of distinct neuropsychiatric symptoms. Abnormal cortical co-alteration pattern in patients with neuropsychiatric symptoms was in somatomotor, vision and frontoparietal regions, with epicenters in somatomotor regions. Apathy, impulse-compulsive behaviors and hallucinations shares structural abnormalities in somatomotor and vision regions, with epicenters in somatomotor regions. In contrast, the cortical abnormalities and epicenters of anxiety and depression were prominent in the default mode network regions. By embedding each symptom within their co-alteration space, we observed a cluster composed of apathy, impulse-compulsive behaviors and hallucinations, while anxiety and depression remained separate. Our findings indicate different structural mechanisms underlie the occurrence and progression of different neuropsychiatric symptoms. Based upon these results, we propose that apathy, impulse-compulsive behaviors and hallucinations are directly related to damage of motor circuit, while anxiety and depression may be the combination effects of primary pathophysiology of Parkinson's disease and psychosocial causes.

Amygdala neuronal dyshomeostasis via 5-HT receptors mediates mood and cognitive defects in Alzheimer's disease

Behavioral changes or neuropsychiatric symptoms (NPSs) are common features in dementia and are associated with accelerated cognitive impairment and earlier deaths. However, how NPSs are intertwined with cognitive decline remains elusive. In this study, we identify that the basolateral amygdala (BLA) is a key brain region that is associated with mood disorders and memory decline in the AD course. During the process from pre- to post-onset in AD, the dysfunction of parvalbumin (PV) interneurons and pyramidal neurons in the amygdala leads to hyperactivity of pyramidal neurons in the basal state and insensitivity to external stimuli. We further demonstrate that serotonin (5-HT) receptors in distinct neurons synergistically regulate the BLA microcircuit of AD rather than 5-HT levels, in which both restrained inhibitory inputs by excessive 5-HT1AR signaling in PV interneurons and depolarized pyramidal neurons via upregulated 5-HT2AR contribute to aberrant neuronal hyperactivity. Downregulation of these two 5-HT receptors simultaneously enables neurons to resist β-amyloid peptides (Aβ) neurotoxicity and ameliorates the mood and cognitive defects. Therefore, our study reveals a crucial role of 5-HT receptors for regulating neuronal homeostasis in AD pathogenesis, and this would provide early intervention and potential targets for AD cognitive decline.

Impulse control disorders in Parkinson's disease: a national Swedish registry study on high-risk treatments and vulnerable patient groups

BACKGROUND

Impulse control disorders (ICDs) are known psychiatric conditions in Parkinson's disease (PD), especially as a side effect of antiparkinsonian therapy. Screening for vulnerable patients and avoiding high-risk treatments can be an effective approach to reduce the ICD burden in patients with PD. Thus, our goal was to identify risk factors for ICDs in PD in the Swedish total population.

METHODS

Our longitudinal study was based on records of all patients with PD in the Swedish National Patient Registries and the Prescribed Drug Register (n=55 235). Patients with incident gambling disorder and other ICDs were compared with a control group on demographic factors, psychiatric comorbidity, antiparkinsonian dopaminergic treatment and therapies for advanced disease. Potential risk factors were analysed using logistic regressions and relative frequency comparisons (Fisher's exact test).

RESULTS

Main predictors for incident gambling disorder were treatment with dopamine agonists (Frequency ratio 1.4, p=0.058), monoamine oxidase B (MAO-B) inhibitors (Frequency ratio 1.8, p=0.006) and a prescription for drugs used in addictive disorders (OR 5.85, 95% CI 2.00 to 17.10). Main predictors for other ICDs were dopamine agonist treatment (frequency ratio 1.6, p=0.003), anxiety disorders (OR 7.04, 95% CI 2.96 to 16.71) and substance use disorders other than alcohol (OR 5.66, 95% CI 1.75 to 18.23).

CONCLUSIONS

Our results support possible risk factors for incident ICDs that had previously been identified, like dopamine agonist treatment and raise additional attention for risk factors like MAO-B inhibitor treatment and specific psychiatric comorbidities. These findings enable tailoring antiparkinsonian therapy to individual patient-specific risk profiles.