Secondary parkinsonism due to drugs, vascular lesions, tumors, trauma, and other insults

Automating the analysis of eye movement for different neurodegenerative disorders

The clinical observation and assessment of extra-ocular movements is common practice in assessing neurodegenerative disorders but remains observer-dependent. In the present study, we propose an algorithm that can automatically identify saccades, fixation, smooth pursuit, and blinks using a non-invasive eye tracker. Subsequently, response-to-stimuli-derived interpretable features were elicited that objectively and quantitatively assess patient behaviors. The cohort analysis encompasses persons with mild cognitive impairment (MCI), Alzheimer's disease (AD), Parkinson's disease (PD), Parkinson's disease mimics (PDM), and controls (CTRL). Overall, results suggested that the AD/MCI and PD groups had significantly different saccade and pursuit characteristics compared to CTRL when the target moved faster or covered a larger visual angle during smooth pursuit. These two groups also displayed more omitted antisaccades and longer average antisaccade latency than CTRL. When reading a text passage silently, people with AD/MCI had more fixations. During visual exploration, people with PD demonstrated a more variable saccade duration than other groups. In the prosaccade task, the PD group showed a significantly smaller average hypometria gain and accuracy, with the most statistical significance and highest AUC scores of features studied. The minimum saccade gain was a PD-specific feature different from CTRL and PDM. These features, as oculographic biomarkers, can be potentially leveraged in distinguishing different types of NDs, yielding more objective and precise protocols to diagnose and monitor disease progression.

Tumoral parkinsonism-Parkinsonism secondary to brain tumors, paraneoplastic syndromes, intracranial malformations, or oncological intervention, and the effect of dopaminergic treatment

INTRODUCTION

Secondary tumoral parkinsonism is a rare phenomenon that develops as a direct or indirect result of brain neoplasms or related conditions.

OBJECTIVES

The first objective was to explore to what extent brain neoplasms, cavernomas, cysts, paraneoplastic syndromes (PNSs), and oncological treatment methods cause parkinsonism. The second objective was to investigate the effect of dopaminergic therapy on the symptomatology in patients with tumoral parkinsonism.

METHODS

A systematic literature review was conducted in the databases PubMed and Embase. Search terms like "secondary parkinsonism," "astrocytoma," and "cranial irradiation" were used. Articles fulfilling inclusion criteria were included in the review.

RESULTS

Out of 316 identified articles from the defined database search strategies, 56 were included in the detailed review. The studies, which were mostly case reports, provided research concerning tumoral parkinsonism and related conditions. It was found that various types of primary brain tumors, such as astrocytoma and meningioma, and more seldom brain metastases, can cause tumoral parkinsonism. Parkinsonism secondary to PNSs, cavernomas, cysts, as well as oncological treatments was reported. Twenty-five of the 56 included studies had tried initiating dopaminergic therapy, and of these 44% reported no, 48% low to moderate, and 8% excellent effect on motor symptomatology.

CONCLUSION

Brain neoplasms, PNSs, certain intracranial malformations, and oncological treatments can cause parkinsonism. Dopaminergic therapy has relatively benign side effects and may relieve motor and nonmotor symptomatology in patients with tumoral parkinsonism. Dopaminergic therapy, particularly levodopa, should therefore be considered in patients with tumoral parkinsonism.

Animal models of Parkinson's disease: bridging the gap between disease hallmarks and research questions

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by motor and non-motor symptoms. More than 200 years after its first clinical description, PD remains a serious affliction that affects a growing proportion of the population. Prevailing treatments only alleviate symptoms; there is still neither a cure that targets the neurodegenerative processes nor therapies that modify the course of the disease. Over the past decades, several animal models have been developed to study PD. Although no model precisely recapitulates the pathology, they still provide valuable information that contributes to our understanding of the disease and the limitations of our treatment options. This review comprehensively summarizes the different animal models available for Parkinson's research, with a focus on those induced by drugs, neurotoxins, pesticides, genetic alterations, α-synuclein inoculation, and viral vector injections. We highlight their characteristics and ability to reproduce PD-like phenotypes. It is essential to realize that the strengths and weaknesses of each model and the induction technique at our disposal are determined by the research question being asked. Our review, therefore, seeks to better aid researchers by ensuring a concrete discernment of classical and novel animal models in PD research.

SARS-COV-2 infection and Parkinson's disease: Possible links and perspectives

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the substantia nigra. The hallmarks are the presence of Lewy bodies composed mainly of aggregated α-synuclein and immune activation and inflammation in the brain. The neurotropism of SARS-CoV-2 with induction of cytokine storm and neuroinflammation can contribute to the development of PD. Interestingly, overexpression of α-synuclein in PD patients may limit SARS-CoV-2 neuroinvasion and degeneration of dopaminergic neurons; however, on the other hand, this virus can speed up the α-synuclein aggregation. The review aims to discuss the potential link between COVID-19 and the risk of PD, highlighting the need for further studies to authenticate the potential association. We have also overviewed the influence of SARS-CoV-2 infection on the PD course and management. In this context, we presented the prospects for controlling the COVID-19 pandemic and related PD cases that, beyond global vaccination and novel anti-SARS-CoV-2 agents, may include the development of graphene-based nanoscale platforms offering antiviral and anti-amyloid strategies against PD.

Therapeutic Effects of Quetiapine and 5-HT1A Receptor Agonism on Hyperactivity in Dopamine-Deficient Mice

Some diseases that are associated with dopamine deficiency are accompanied by psychiatric symptoms, including Parkinson’s disease. However, the mechanism by which this occurs has not been clarified. Previous studies found that dopamine-deficient (DD) mice exhibited hyperactivity in a novel environment. This hyperactivity is improved by clozapine and donepezil, which are used to treat psychiatric symptoms associated with dopamine deficiency (PSDD). We considered that DD mice could be used to study PSDD. In the present study, we sought to identify the pharmacological mechanism of PSDD. We conducted locomotor activity tests by administering quetiapine and drugs that have specific actions on serotonin (5-hydroxytryptamine [5-HT]) receptors and muscarinic receptors. Changes in neuronal activity that were induced by drug administration in DD mice were evaluated by examining Fos immunoreactivity. Quetiapine suppressed hyperactivity in DD mice while the 5-HT_1A receptor antagonist WAY100635 inhibited this effect. The number of Fos-positive neurons in the median raphe nucleus increased in DD mice that exhibited hyperactivity and was decreased by treatment with quetiapine and 5-HT_1A receptor agonists. In conclusion, hyperactivity in DD mice was ameliorated by quetiapine, likely through 5-HT_1A receptor activation. These findings suggest that 5-HT_1A receptors may play a role in PSDD, and 5-HT_1A receptor-targeting drugs may help improve PSDD.

Direct Medical Costs of Parkinson's Disease in Southern China: A Cross-Sectional Study Based on Health Insurance Claims Data in Guangzhou City

Background: Parkinson’s disease (PD) is the second most common neurodegenerative disorder. This study aims to evaluate the direct medical costs of patients with PD using a large sample from an entire city and to identity the potential factors correlating with their inpatient costs in Guangzhou City, Southern China. Methods: This retrospective cross-sectional study uses data obtained from the Urban Employee-based Basic Medical Insurance (UEBMI) and the Urban Resident-based Basic Medical Insurance (URBMI) administrative claims databases in Guangzhou City from 2008 to 2012. The total sample was comprised of 2660 patients with PD. Costs were evaluated for the total sample and by types of insurance. The composition of costs was compared between the UEBMI and URBMI subgroups. The extended estimating-equations model was applied to identify the potential impact factors influencing the inpatient costs. Results: The direct medical costs per patient with PD were CNY 14,514.9 (USD 2299.4) in 2012, consisting of inpatient costs of CNY 13,551.4 and outpatient costs of CNY 963.5. The medication costs accounted for the largest part (50.3%). The inpatient costs of PD patients under the UEBMI scheme (CNY 13,651.0) were significantly higher than those of patients in the URBMI subgroup (CNY 12,402.2) (p < 0.05). The proportion of out-of-pocket spending out of inpatient and outpatient costs for UEBMI beneficiaries (24.3% and 56.1%) was much lower than that for patients under the URBMI scheme (47.9% and 76.2%). The regression analysis suggested that types of insurance, age, hospital levels, length of stay (LOS) and comorbidities were significantly correlated with the inpatient costs of patients with PD. Conclusions: The direct medical costs of patients with PD in China were high compared to the GDP per capita in Guangzhou City and different between the two evaluated types of insurance. Patients with the UEBMI scheme, of older age, with comorbidities, staying in tertiary hospitals and with longer LOS had significantly higher inpatient costs. Thus, policymakers need to reduce the gaps between the two urban insurance schemes in benefit levels, provide support for the development of a comprehensive long-term care insurance system and promote the use of telemedicine in China.

Brain Tumor Presenting with Parkinsonism

Movement disorders caused by brain tumors are rare. The diagnosis of idiopathic Parkinson's disease (PD) is based foremost on clinical findings. However, not performing imaging already within the initial diagnostic workup in patients presenting with symptoms of PD can delay or miss a serious diagnosis and consequently proper treatment. We describe and discuss a 59-year-old female patient who presented for several months of increasing tremor in her left hand, which was caused by a large meningioma located in the right frontal area, pressing on the right frontal lobe and nucleus lenticularis.

The etiopathogenetic and pathophysiological spectrum of parkinsonism

Parkinsonism is a syndrome characterized by bradykinesia, rigidity, and tremor. Parkinsonism is a common manifestation of Parkinson's disease and other neurodegenerative diseases referred to as atypical parkinsonism. However, a growing body of clinical and scientific evidence indicates that parkinsonism may be part of the phenomenological spectrum of various neurological conditions to a greater degree than expected by chance. These include neurodegenerative conditions not traditionally classified as movement disorders, e.g., dementia and motor neuron diseases. In addition, parkinsonism may characterize a wide range of central nervous system diseases, e.g., autoimmune diseases, infectious diseases, cerebrospinal fluid disorders (e.g., normal pressure hydrocephalus), cerebrovascular diseases, and other conditions. Several pathophysiological mechanisms have been identified in Parkinson's disease and atypical parkinsonism. Conversely, it is not entirely clear to what extent the same mechanisms and key brain areas are also involved in parkinsonism due to a broader etiopathogenetic spectrum. We aimed to provide a comprehensive and up-to-date overview of the various etiopathogenetic and pathophysiological mechanisms of parkinsonism in a wide spectrum of neurological conditions, with a particular focus on the role of the basal ganglia involvement. The paper also highlights potential implications in the diagnostic approach and therapeutic management of patients. This article is part of the Special Issue "Parkinsonism across the spectrum of movement disorders and beyond" edited by Joseph Jankovic, Daniel D. Truong and Matteo Bologna.

Calcium Channel blockers are associated with reduced risk of Parkinson's disease in patients with hypertension: A population-based retrospective cohort study

BACKGROUND

The use of dihydropyridine calcium channel blockers (DCCBs) was proposed to reduce the risk of Parkinson's disease (PD). This study aimed to evaluate the association between DCCB and its dose effect and the risk of PD in patients with newly diagnosed hypertension.

METHODS

This population-based retrospective cohort study enrolled 107,207 patients with newly diagnosed hypertension, between 2001 and 2013, from Taiwan's National Health Insurance Research Database. Patients who had PD before hypertension or were taking antipsychotics for more than 30 days in the 6 months prior to the end of the observation period were excluded. A Cox proportional hazard model was used to estimate the risk of PD in different groups. The dose-related effects of DCCB on the risk of PD were evaluated according to the cumulative defined daily dose (DDD).

RESULTS

We observed 832 (1.2%) PD cases in patients treated with DCCB as compared to 950 (2.4%) PD cases in those not treated with DCCB, during a median follow-up duration of 8.3 years and 6.2 years, respectively. The risk of PD in the DCCB-treated group (hazard ratio [HR] = 0.50) was significantly lower than that in the group without DCCB treatment. DCCB reduced the risk of PD in a dose-dependent manner, with HRs ranging from 0.61 to 0.37 for DDDs of 90-180 to >720.

CONCLUSIONS

DCCB treatment was associated with a significantly reduced risk of PD in patients with newly diagnosed hypertension. Further clinical trials are needed to confirm the proposed neuroprotective effects of DCCB in PD.

"Metal elements and pesticides as risk factors for Parkinson's disease - A review"

Essential metals including iron (Fe) and manganese (Mn) with known physiological functions in human body play an important role in cell homeostasis. Excessive exposure to these essential as well as non-essential metals including mercury (Hg) and Aluminum (Al) may contribute to pathological conditions, including PD. Each metal could be toxic through specific pathways. Epidemiological evidences from occupational and ecological studies besides various in vivo and in vitro studies have revealed the possible pathogenic role and neurotoxicity of different metals. Pesticides are substances that aim to mitigate the harm done by pests to plants and crops, and are extensively used to boost agricultural production. This review provides an outline of our current knowledge on the possible association between metals and PD. We have discussed the potential association between these two, furthermore the chemical properties, biological and toxicological aspects as well as possible mechanisms of Fe, Mn, Cu, Zn, Al, Ca, Pb, Hg and Zn in PD pathogenesis. In addition, we review recent evidence on deregulated microRNAs upon pesticide exposure and possible role of deregulated miRNA and pesticides to PD pathogenesis.

Gut Microbiota Approach-A New Strategy to Treat Parkinson's Disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by neuronal loss and dysfunction of dopaminergic neurons located in the substantia nigra, which contain a variety of misfolded α-synuclein (α-syn). Medications that increase or substitute for dopamine can be used for the treatment of PD. Recently, numerous studies have shown gut microbiota plays a crucial role in regulating and maintaining multiple aspects of host physiology including host metabolism and neurodevelopment. In this review article, the role of gut microbiota in the etiological mechanism of PD will be reviewed. Furthermore, we discussed current pharmaceutical medicine-based methods to prevent and treat PD, followed by describing specific strains that affect the host brain function through the gut-brain axis. We explained in detail how gut microbiota directly produces neurotransmitters or regulate the host biosynthesis of neurotransmitters. The neurotransmitters secreted by the intestinal lumen bacteria may induce epithelial cells to release molecules that, in turn, can regulate neural signaling in the enteric nervous system and subsequently control brain function and behavior through the brain-gut axis. Finally, we proved that the microbial regulation of the host neuronal system. Endogenous α-syn can be transmitted long distance and bidirectional between ENS and brain through the circulatory system which gives us a new option that the possibility of altering the community of gut microbiota in completely new medication option for treating PD.

From Psychiatry to Neurology and Endocrinology: A Case of Hypoparathyroidism

A 31-year-old male patient developed extrapyramidal symptoms while on treatment for depression. He was investigated and found to suffer from hypoparathyroidism. He had calcification in the brain, signs and symptoms of neuromuscular irritability, and QT prolongation on electrocardiogram. He was treated with calcium carbonate and calcitriol. Although he had marked improvement, bradykinesia persisted. This report highlights the importance of maintaining a high index of suspicion for hypocalcemia, and the importance of searching for an organic basis for psychiatric symptoms.