Drug-induced parkinsonism

Subcortical structure alteration in patients with drug-induced parkinsonism: Evidence from neuroimaging

Parkinson's Disease (PD) and Drug-induced parkinsonism (DIP) are the most common subtypes of parkinsonism, yet no studies have reported that the subcortical volume alterations in DIP patients. This study aimed to identify specific alterations of subcortical structures volume in DIP patients, and investigate association between the subcortical structure modifications and clinical symptoms. We recruited 27 PD patients, 25 DIP patients and 30 healthy controls (HCs). The clinical symptom-related parameters (Unified Parkinson's Disease Rating Scale, UPDRS) were evaluated. Structural imaging was performed on a 3.0 T scanner, and volumes of subcortical structures were obtained using FreeSurfer software. Analysis of covariance (ANCOVA) and partial correlation analysis were performed. DIP group had significantly smaller volume of the thalamus, pallidum, hippocampus and amygdala compared to HCs. ROC curve analysis demonstrated that the highest area under curve (AUC) value was in the right pallidum (AUC = 0.831) for evaluating the diagnostic efficacy in DIP from HCs. Moreover, the volumes of the putamen, hippocampus and amygdala were negatively correlated with UPDRSII in the DIP patients. The volume of the amygdala was negatively correlated with UPDRSIII. The present study provides novel information regarding neuroanatomical alteration of subcortical nuclei in DIP patients, suggesting that these methods might provide the basis for early diagnosis and differential diagnosis of DIP.

Neurocognitive Impairment and Social Cognition in Parkinson's Disease Patients

In addition to motor symptoms, neurocognitive impairment (NCI) affects patients with prodromal Parkinson's disease (PD). NCI in PD ranges from subjective cognitive complaints to dementia. The purpose of this review is to present the available evidence of NCI in PD and highlight the heterogeneity of NCI phenotypes as well as the range of factors that contribute to NCI onset and progression. A review of publications related to NCI in PD up to March 2023 was performed using PubMed/Medline. There is an interconnection between the neurocognitive and motor symptoms of the disease, suggesting a common underlying pathophysiology as well as an interconnection between NCI and non-motor symptoms, such as mood disorders, which may contribute to confounding NCI. Motor and non-motor symptom evaluation could be used prognostically for NCI onset and progression in combination with imaging, laboratory, and genetic data. Additionally, the implications of NCI on the social cognition of afflicted patients warrant its prompt management. The etiology of NCI onset and its progression in PD is multifactorial and its effects are equally grave as the motor effects. This review highlights the importance of the prompt identification of subjective cognitive complaints in PD patients and NCI management.

Evaluate the in vitro effect of anthracycline and alkylating cytophosphane chemotherapeutics on dopaminergic neurons

BACKGROUND

Iatrogenesis is an inevitable global threat to healthcare that drastically increases morbidity and mortality. Cancer is a fatal pathological condition that affects people of different ages, sexes, and races around the world. In addition to the detrimental cancer pathology, one of the most common contraindications and challenges observed in cancer patients is severe adverse drug effects and hypersensitivity reactions induced by chemotherapy. Chemotherapy-induced cognitive neurotoxicity is clinically referred to as Chemotherapy-induced cognitive impairment (CICI), chemobrain, or chemofog. In addition to CICI, chemotherapy also causes neuropsychiatric issues, mental disorders, hyperarousal states, and movement disorders. A synergistic chemotherapy regimen of Doxorubicin (Anthracycline-DOX) and Cyclophosphamide (Alkylating Cytophosphane-CPS) is indicated for the management of various cancers (breast cancer, lymphoma, and leukemia). Nevertheless, there are limited research studies on Doxorubicin and Cyclophosphamide's pharmacodynamic and toxicological effects on dopaminergic neuronal function.

AIM

This study evaluated the dopaminergic neurotoxic effects of Doxorubicin and Cyclophosphamide.

METHODS AND RESULTS

Doxorubicin and Cyclophosphamide were incubated with dopaminergic (N27) neurons. Neuronal viability was assessed using an MTT assay. The effect of Doxorubicin and Cyclophosphamide on various prooxidants, antioxidants, mitochondrial Complex-I & IV activities, and BAX expression were evaluated by Spectroscopic, Fluorometric, and RT-PCR methods, respectively. Prism-V software (La Jolla, CA, USA) was used for statistical analysis. Chemotherapeutics dose-dependently inhibited the proliferation of the dopaminergic neurons. The dopaminergic neurotoxic mechanism of Doxorubicin and Cyclophosphamide was attributed to a significant increase in prooxidants, a decrease in antioxidants, and augmented apoptosis without affecting mitochondrial function.

CONCLUSION

This is one of the first reports that reveal Doxorubicin and Cyclophosphamide induce significant dopaminergic neurotoxicity. Thus, Chemotherapy-induced adverse drug reaction issues substantially persist during and after treatment and sometimes never be completely resolved clinically. Consequently, failure to adopt adequate patient care measures for cancer patients treated with certain chemotherapeutics might substantially raise the incidence of numerous movement disorders.

Increasing incidence of Parkinson's disease in patients with epilepsy: A Nationwide cohort study

BACKGROUND

Although epilepsy is an uncommon comorbidity of Parkinson's disease (PD), the exact incidence of PD among the patients with epilepsy is not clarified yet.

OBJECTIVES

We aimed to estimate the incidence of PD in patients with epilepsy and explore the association between epilepsy and PD.

METHODS

Epilepsy patients enrolled in the National Health Insurance Service Health Screening Cohort (NHIS-HealS) (2002-2013) between 2003 and 2007 were set up as the experimental group. The major outcome was the occurrence of PD. Non-epilepsy patients were obtained through Propensity Score Matching of 'greedy nearest neighbor' algorithm in 1:1 ratio. The Cox Proportional Hazards model was used to calculate PD incidence and hazard ratio (HR).

RESULTS

A total of 10,510 patients were finally included in the study, which contained 5255 patients in epilepsy and non-epilepsy groups, respectively. During the follow-up period, 85 patients with Parkinson's disease among 5255 patients with epilepsy and 57 patients with Parkinson's disease among 5255 patients without epilepsy occurred. The 10,000 Person-Year (PY), representing the number of PD patients per 10,000 per year, was 21.38 in the epilepsy group and 11.18 in the non-epilepsy group. When all variables were adjusted, it was found that the epilepsy group had a 2.19 times significantly higher risk of developing Parkinson's disease than the control group (The adjusted HR: 2.19 (95% CI, 1.55-3.12)).

CONCLUSION

This study indicates an increased risk of PD in patients with epilepsy. However, further research is needed to prove an exact causal relationship between these two brain disorders.

Drug clustering to anticipate new aspects of drug safety profile: Application to gabapentinoids and other voltage-gated calcium channel ligand drugs

AIMS

Gabapentin and pregabalin bind to α2-δ subunit of voltage-gated calcium channels (Cav ). Other drugs targeting Cav include cardiovascular calcium channel blockers (CCBs) and anticonvulsants (levetiracetam, ethosuximide and zonisamide). In addition to pharmacodynamics, the safety profile of gabapentinoids seems to overlap with the one of cardiovascular CCBs (oedema) and Cav -blocking anticonvulsants (suicide and ataxia). The objective of this study was to cluster the safety profile of different Cav -ligand drugs by focusing on whether gabapentinoids present a distinct adverse drug reaction (ADR) signature from cardiovascular CCBs and anticonvulsants.

METHODS

We extracted all ADRs with at least one significant disproportionate reporting (reporting odds ratio) related to gabapentinoids, CCBs or anticonvulsants in VigiBase. After principal component analysis preprocessing, a hierarchical ascendent classification was performed to cluster gabapentinoids and other Cav -ligand drugs that share a similar ADR signature. The robustness of the results was determined through four sensitivity analyses, varying on the dataset or the clustering method.

RESULTS

A total of 16 drugs and 65 ADRs were included. Gabapentinoids were in Cluster #1, which included eight other drugs (isradipine, nicardipine, lacidipine, lercanidipine, ethosuximide, levetiracetam, zonisamide and nimodipine). Cluster #2 contained two drugs (diltiazem and verapamil) and Cluster #3 contained four drugs (amlodipine, felodipine, nifedipine and nitrendipine). The clustering results were consistent in all sensitivity analyses.

CONCLUSIONS

The safety profile of gabapentinoids overlaps with those of some dihydropyridine CCBs and Cav -blocking anticonvulsants. These results could be used to anticipate some unidentified ADRs of gabapentinoids from information accumulated with older drugs and sharing a common molecular target and ADR signature.

Prevention of Parkinson's Disease: From Risk Factors to Early Interventions

Parkinson's disease (PD) is a debilitating neurological disorder characterized by progressively worsening motor dysfunction. Currently, available therapies merely alleviate symptoms, and there are no cures. Consequently, some researchers have now shifted their attention to identifying the modifiable risk factors of PD, with the intention of possibly implementing early interventions to prevent the development of PD. Four primary risk factors for PD are discussed including environmental factors (pesticides and heavy metals), lifestyle (physical activity and dietary intake), drug abuse, and individual comorbidities. Additionally, clinical biomarkers, neuroimaging, biochemical biomarkers, and genetic biomarkers could also help to detect prodromal PD. This review compiled available evidence that illustrates the relationship between modifiable risk factors, biomarkers, and PD. In summary, we raise the distinct possibility of preventing PD via early interventions of the modifiable risk factors and early diagnosis.

Chronic diseases and multimorbidity patterns, their recent onset, and risk of new-onset Parkinson's disease and related functional degeneration in older adults: a prospective cohort study

Background

Certain chronic diseases contribute to increased risks of Parkinson's disease (PD), but the association between time-varying multimorbidity patterns and new-onset PD remains underexplored.

Methods

Data were from the Survey of Health, Ageing and Retirement in Europe (SHARE) waves 5-8 conducted between January 2013 and March 2020. Eleven chronic diseases were included, with ≥2 denoting multimorbidity. Three multimorbidity patterns were further defined: somatic multimorbidity (SMM), neuropsychiatric multimorbidity (NPM), and cardiometabolic multimorbidity (CMM). PD-related function degeneration included functional limitations, mobility limitations, depressive symptoms, and cognitive decline. Time-dependent analyses, competing-risk analyses, and mixed-effect models were utilised.

Findings

In this prospective cohort study, 557 developed new-onset PD during follow-ups among 64,273 participants included at baseline, as defined by participants' self-reported physician diagnoses. Participants with (vs. without) multimorbidity, SMM, NPM, and CMM were at 1.40-2.70 times higher PD risk after considering the competing role of all-cause death, which remained significant in all sensitivity analyses and were more pronounced in lower-income participants (P for interaction <0.05). Similarly, they tended to develop functional degeneration faster than those without these multimorbidity patterns (P < 0.05). Participants with recent-onset (newly diagnosed in 2015) multimorbidity patterns were at 1.45-3.72 times higher risk of PD than those never diagnosed. Interestingly, they were at comparable or even higher (though P values for >0.05) PD risk compared to participants with multimorbidity patterns diagnosed in 2013 or before. Furthermore, recent-onset (vs. prior diagnosed) NPM exhibited faster functional deterioration and cognitive decline (P for difference <0.05).

Interpretation

Our findings suggest that promoting early prevention of multimorbidity, especially recent-onset multimorbidity and NPM, could prevent some subsequent cases of PD and related functional degeneration among older adults. However, further studies are needed to confirm this association.

Funding

The National Key Research and Development Program, Ministry of Science and Technology, China; Zhongnanshan Medical Foundation of Guangdong Province; Major Project of the National Social Science Fund of China; Fundamental Research Funds for the Central Universities.

Effects of defoliant exposure and medication use on the development of Parkinson's disease in veterans

BACKGROUND

Vietnam-era veterans were exposed to Agent Orange (AO), which is associated with a high prevalence of Parkinson's disease (PD). However, little is known about the development of PD-like symptoms caused by drug-induced parkinsonism (DIP) in such populations. This study aimed to investigate PD incidence and PD risk following exposure to AO or DIP-risk drugs in veterans.

METHODS

A retrospective cohort study was conducted using 12 years (2009-2020) of electronic medical records of the Veterans Health Service Medical Center, the largest Veterans Affairs hospital in South Korea (n = 37,246; 100% male; age, 65.57 ± 8.12 years). Exposure to AO or DIP-risk drugs, including antipsychotic, prokinetic, anti-epileptic, dopamine-depleting and anti-anginal agents, was assessed in veterans with PD, operationally defined as having a PD diagnosis and one or more prescriptions for PD treatment. The PD risk was calculated using multiple logistic regression analysis adjusted for age and comorbidities.

RESULTS

The rates of DIP-risk drug use and AO exposure were 37.92% and 62.62%, respectively. The PD incidence from 2010 to 2020 was 3.08%; 1.30% with neither exposure, 1.63% with AO exposure, 4.38% with DIP-risk drug use, and 6.33% with both. Combined exposure to AO and DIP-risk drugs increased the PD risk (adjusted odds ratio = 1.68, 95% confidence interval, 1.36-2.08, P < 0.001).

CONCLUSIONS

The PD incidence was 1.31 times higher with AO exposure alone and 1.68 times higher with AO exposure and DIP-risk drug use. The results suggest the necessity for careful monitoring and DIP-risk drug prescription in patients with AO exposure.

Prevalence and causative drugs of drug-induced Parkinsonism in pediatric patients

Although several studies provided evidence on the epidemiology of drug-induced Parkinsonism (DIP) and its causative drugs, it is still limited in pediatrics. This study aimed to investigate the prevalence and risk of DIP in pediatrics. We used the Health Insurance Review and Assessment Service-Pediatric Patients Sample in Korea between 2010 and 2017 to estimate the annual prevalence of DIP and causative drug use using a cross-sectional design. The risk of DIP associated with causative drugs was evaluated using a case-crossover design. Adjusted odds ratios (aOR) with 95% confidence intervals (CI) were calculated using a conditional logistic regression. A total of 2925 pediatric patients had diagnosed with DIP from 2010 to 2017. Most patients were aged between 12 and19 years old, and 99.8% had any diagnosis of mental health disorder (MHD). During the study period, the prevalence of DIP increased by 10.0-fold from 2010 to 2017. All causative drugs showed a corresponding increase in their use, with atypical antipsychotics being the most prominent (increase ratio, 2.07). For both in the prevalence of DIP and atypical antipsychotic use, the increment was much bigger in patients with non-psychotic MHD than that in patients with psychotic MHD. In the case-crossover study, antipsychotics showed the largest aOR with DIP. Risperidone among antipsychotics showed the highest risk for DIP (aOR = 7.09, 95% CI = 3.83-13.09), followed by aripiprazole (aOR = 5.03, 95% CI = 2.88-8.80). This study suggests that the increase in DIP prevalence in pediatric patients might be because of the increased use of atypical antipsychotics.

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.

Treatment Changes and Prognoses in Patients with Incident Drug-Induced Parkinsonism Using a Korean Nationwide Healthcare Claims Database

This retrospective cohort study assessed treatment changes and prognoses after incident drug-induced parkinsonism (DIP). We used the National Health Insurance Service's National Sample Cohort database in South Korea. We selected patients diagnosed with incident DIP and given prescriptions to take offending drugs (antipsychotics, gastrointestinal (GI) motility drugs, or flunarizine) for a period of time that overlapped with the time of DIP diagnosis during 2004-2013. The proportion of patients experiencing each type of treatment change and prognosis was assessed for 2 years after DIP diagnosis. We identified 272 patients with incident DIP (51.9% of patients were aged ≥ 60 years and 62.5% of them were women). Switching (38.4%) and reinitiation (28.8%) were the most common modifications in GI motility drug users, whereas dose adjustment (39.8%) and switching (23.0%) were common in antipsychotic users. The proportion of persistent users was higher among antipsychotic users (7.1%) than that among GI motility drug users (2.1%). Regarding prognosis, 26.9% of patients experienced DIP recurrence or persistence, the rate being the highest in persistent users and the lowest in patients who discontinued the drug. Among patients with incident DIP diagnoses, the patterns of treatment change and prognosis differed across the types of offending drugs. Over 25% of patients experienced DIP recurrence or persistence, highlighting the need for an effective strategy to prevent DIP.

Risk of parkinsonism and related movement disorders with gabapentinoids or tramadol: A case-crossover study

INTRODUCTION

A safety signal concerning parkinsonism and related movement disorders with gabapentinoids (gabapentin and pregabalin) or tramadol was detected by reviewing individual case reports and data mining in spontaneous report databases. Well-designed pharmacoepidemiological studies are needed to assess the signal.

OBJECTIVE

This study aimed to investigate the association of exposure to gabapentinoids or tramadol with the risk of parkinsonism and related movement disorders.

METHODS

We conducted a case-crossover study using a Japanese electronic medical records database. Patients with newly diagnosed parkinsonism or related movement disorders between January 1, 2007, and April 14, 2019, were identified. The diagnosis date of outcomes was defined as the index date. We assessed the exposure of each patient to gabapentinoids or tramadol during a 90-day hazard period ending 1 day before the index date and in three 90-day reference periods. Multivariable conditional logistic regression models were employed to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs). To confirm the robustness of the primary findings, we also performed sensitivity analyses using a case-case-time-control design, a different time window for hazard and reference periods, a different definition of outcome, and different number of reference periods.

RESULTS

A total of 28,972 eligible cases were included in the primary analysis. Exposure to gabapentinoids (aOR, 2.12; 95% CI, 1.73-2.61) and tramadol (aOR, 2.04; 95% CI, 1.57-2.64) was associated with increased risk. Results were consistent across sensitivity analyses.

CONCLUSION

Our findings serve as a caution to physicians who prescribe gabapentinoids or tramadol in routine clinical practice.

Permanent non-progressive cinnarizine and flunarizine-induced parkinsonism: An under-recognized tardive syndrome in the elderly?

Secondary parkinsonism induced by exposure to dopamine (DA) receptor antagonists as first and second generation antipsychotics, DA storage depleters, calcium channel blockers, benzamides substituted and other classes of drugs is traditionally believed to be completely reversible in most of patients following withdrawal of the offending drug even though after a variable time delay. The lack of recovery or initial full recovery with subsequent development of progressive parkinsonism has been regarded to result from an underlying subclinical degenerative process like PD unmasked by the inducing drug. These well-recognized clinical outcomes of drug-induced parkinsonism (DIP) have disregarded the existence of another outcome, characterized by permanent non-progressive parkinsonism. This syndrome may fullfil the criteria of tardive parkinsonism, a controversial entity currently referred to as a persistent condition without indication of its long-term course and clinical features. On reviewing the published literature on DIP, we have identified two prospective long-term follow-up of elderly patients in which parkinsonism induced by the calcium channel antagonists cinnarizine and flunarizine became permanent and non-progressive following drug discontinuation in a non-negligible proportion of patients, consistent with the clinical concept of a true tardive syndrome, according to currently accepted criteria. The authors hypothesize that the development of tardive parkinsonism might be due to a neurotoxic effect of the pharmacodynamic proprieties of the calcium channel blockers and their metabolites, exerted on post-synaptic striatal neurons and/or a neurotoxic damage on presynaptic DA neurons in patients without an underlying subclinical degenerative parkinsonism, so accounting for the stable and non-progressive course over time.

Exploring the prevalence and characteristics of adverse drug events among older adults in South Korea using a national health insurance database

Background: Adverse drug events (ADEs) in the elderly frequently occur because of their multiple chronic diseases and complexity of drug therapy. To better understand adverse drug events, the prevalence and characteristics of adverse drug events in elderly South Korean patients were assessed.

Methods: The National Health Insurance databases for 2015 and 2016 were used for the analysis. We included patients aged ≥65 years that had at least one claim with the diagnosis codes ‘drug-induced,’ ‘poisoning by drug,’ and ‘vaccine-associated’ each year for the base-case analysis. To minimize the underestimation of adverse drug event prevalence, we also used an extended definition analysis by adding the ‘adverse drug event very likely’ codes. We estimated the prevalence of adverse drug events by sex, age group, and type of insurance and examined the frequent types of adverse drug events in 2015 and 2016.

Results: In the base-case analysis, adverse drug event prevalence in individuals aged 65 years and older was 2.75% in 2015 and 2.77% in 2016. With advanced age, the prevalence of adverse drug event tended to increase, peaking in the age group of 75–79 years. In addition, the adverse drug event prevalence was higher in females and Medical Aid enrollees. The most frequently occurring adverse drug event was ‘allergy, unspecified,’ followed by ‘other drug-induced secondary parkinsonism,’ and ‘generalized skin eruption due to drugs and medicaments.’ When we examined the extended definition analysis, the prevalence of adverse drug events was 4.47% in 2015 and 4.52% in 2016, which significantly increased from those estimated in the base-case analysis.

Conclusion: Among the older adults, the prevalence of adverse drug event was higher in advanced age, females, and Medical Aid enrollees. In particular, allergy and drug-induced secondary parkinsonism frequently occurred. This study provides evidence that health policies addressing the prevention and management of adverse drug events should be a priority for the most vulnerable elderly patients.

Parkinsonism Attenuation by Antihistamines via Downregulating the Oxidative Stress, Histamine, and Inflammation

Parkinson disease (PD) is a neurodegenerative disorder of the motor activity of the brain, regulated by dopaminergic neurons of substantia nigra, resulting in an increased density of histaminergic fibers. This study was aimed to evaluate the effects of H1 antagonist's ebastine and levocetirizine in PD per se and in combination. Animals were divided into 9 groups (n = 10). Group 1 received carboxymethyl cellulose CMC (1 mL/kg). Group II was treated with haloperidol (1 mg/kg) (diseased group). Group III was treated with levodopa/carbidopa (levo 20 mg/kg). Groups IV and V were treated with ebastine at dose levels of 2 and 4 mg/kg, respectively. Groups VI and VII were treated with levocetirizine at dose levels of 0.5 and 1 mg/kg, respectively. Group VIII was treated with ebastine (4 mg/kg) + levo (20 mg/kg) in combination. Group IX was treated with levocetirizine (1 mg/kg) + levo (20 mg/kg). PD was induced with haloperidol (1 mg/kg iv, once daily for 23 days) for a duration of 30 min. Behavioral tests like rotarod, block and triple horizontal bars, actophotometer, and open field were performed. Biochemical markers of oxidative stress, i.e., SOD, CAT, GSH, MDA, dopamine, serotonin, and nor-adrenaline and nitrite, were determined. Histamine, mRNA expression of α-synuclein, and TNF-α level in the serum and brain of mice were analyzed. Endogenous biochemical markers were increased except mRNA expression of α-synuclein, which was reduced. In combination therapy with the standard drug, ebastine (4 mg/kg) significantly improved the cataleptic state and dopamine levels, but no significant difference in the renal and liver functioning tests was observed. This study concluded that ebastine (4 mg/kg) might work in the treatment of PD as it improves the cataleptic state in haloperidol-induced catalepsy.

Time to onset of drug-induced parkinsonism: Analysis using a large Japanese adverse event self-reporting database

Whether there are differences in the time to onset of drug-induced parkinsonism (DIP) depending on the type of drugs causing DIP remains uncertain, so that question was investigated here using a large real-world database. Fourteen DIP-related drug categories were defined to perform a disproportionality analysis using a large Japanese pharmacovigilance database containing more than 600,000 self-reported adverse events (AEs) recorded between April 2004 and September 2021 to identify AEs indicating "parkinsonism" in association with the defined drug categories. The time from drug administration to the onset of DIP was comparatively analyzed. Results indicated that the median time to onset was shorter than 1 month in more than half of the cases of DIP; it was shortest with peripheral dopamine antagonists (median: 0.1 weeks), followed by benzodiazepine (median: 0.5 weeks), butyrophenone (median: 0.7 weeks), novel antidepressants (median: 2.5 weeks), atypical antipsychotics (median: 3.3 weeks), other antidepressants (e.g., lithium, median: 3.7 weeks), and benzamide (median: 4.5 weeks). In contrast, anti-dementia drugs, tricyclic antidepressants, and antiepileptic drugs resulted in a relatively longer time to onset (median: 9.9, 17.2, and 28.4 weeks, respectively). In addition, a maximum delay of even longer than 2 years was reported for benzamide (846 weeks), anti-Parkinsonism drugs (382 weeks), phenothiazine (232 weeks), atypical antipsychotics (167 weeks), anti-dementia drugs (161 weeks), and benzodiazepines (120 weeks). The current results suggested that the characteristics of the time to onset of DIP may substantially differ depending on the type of drug causing that DIP. This finding may help when diagnosing patients with parkinsonism.

Doxorubicin induced aggregation of α-synuclein: Insights into the mechanism of drug induced Parkinsonism

The aggregation of α-synuclein is a prominent feature of Parkinson's disease. It is induced by factors such as genetic mutations and presence of metal salts leading to Parkinson's like symptoms. Existing case studies show that patients undergoing cancer chemotherapeutics are also prone to developing Parkinson's like symptoms. However, the underlying cause behind onset of these symptoms is not understood. It is not clear whether the administration of chemotherapeutic drugs alter the structural stability of α-synuclein. In the present study, we address this question by looking into the effect of chemotherapeutic drug namely doxorubicin on the α-synuclein stability. Using complementary spectroscopic, molecular docking and imaging techniques, we observe that doxorubicin interacted with central aggregation prone region of α-synuclein and induces destabilization leading to aggregation. We also show that the combination of doxorubicin and L-DOPA drugs impedes the α-synuclein aggregation. This may explain the reason behind the effectiveness of using L-DOPA against Parkinson's like symptoms.

Protective Effect of Renin-Angiotensin System Inhibitors on Parkinson's Disease: A Nationwide Cohort Study

Background: Renin-angiotensin system (RAS) inhibitors have been suggested as protective agents in Parkinson's disease (PD). However, epidemiological evidence on the association between RAS inhibitors and the development of PD is inconsistent. Objectives: To investigate the effect of RAS inhibitors on PD risk in patients with ischemic heart disease (IHD) by type and cumulative duration of RAS inhibitors and their degree of blood-brain barrier (BBB) penetration ability. Methods: This was a propensity score-matched retrospective cohort study using 2008-2019 healthcare claims data from the Korean Health Insurance Review and Assessment database. The association between RAS inhibitor use and PD in patients with IHD was evaluated using multivariate Cox proportional hazard regression analysis. The risks are presented as adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs). Results: Over a 10-year follow-up, 1,086 of 62,228 IHD patients developed PD. The Cox regression model showed that the use of RAS inhibitors was significantly associated with a lower risk of PD (aHR = 0.75; 95% CI 0.66-0.85) than the non-use of RAS inhibitors. Specifically, this reduced risk of PD only remained with the use of BBB-crossing angiotensin II receptor blockers (ARBs) (aHR = 0.62; 95% CI = 0.53-0.74), and this association was more definite with an increasing cumulative duration. A significantly reduced risk of PD was not observed with the use of BBB-crossing angiotensin-converting enzyme inhibitors. Conclusions: The use of ARBs with BBB-penetrating properties and a high cumulative duration significantly reduces the risk of PD in IHD patients. This protective effect could provide insight into disease-modifying drug candidates for PD.

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.

Decreased thalamic monoamine availability in drug-induced parkinsonism

Drug-induced parkinsonism (DIP) is caused by a dopamine receptor blockade and is a major cause of misleading diagnosis of Parkinson’s disease (PD). Striatal dopamine activity has been investigated widely in DIP; however, most studies with dopamine transporter imaging have focused on the clinical characteristics and prognosis. This study investigated differences in striatal subregional monoamine availability among patients with DIP, normal controls, and patients with early PD. Thirty-five DIP patients, the same number of age-matched PD patients, and 46 healthy controls were selected for this study. Parkinsonian motor status was examined. Brain magnetic resonance imaging and positron emission tomography with ¹⁸F-N-(3-fluoropropyl)-2beta-carbon ethoxy-3beta-(4-iodophenyl) nortropane were performed, and the regional standardized uptake values were analyzed with a volume-of-interest template and compared among the groups. The groups were evenly matched for age, but there were numerically more females in the DIP group. Parkinsonian motor symptoms were similar in the DIP and PD groups. Monoamine availability in the thalamus of the DIP group was lower than that of the normal controls and similar to that of the PD group. In other subregions (putamen, globus pallidus, and ventral striatum), monoamine availability in the DIP group and normal controls did not differ and was higher than that in the PD group. This difference compared to healthy subject suggests that low monoamine availability in the thalamus could be an imaging biomarker of DIP.

Diagnostic accuracy of brain stem auditory evoked response in distinguishing drug-induced parkinsonism from Parkinson'sdisease

OBJECTIVES

Brainstem auditory evoked response (BAER) is a non-invasive modality that can be used to investigate brainstem neuronal function in movement disorders. The differentiation between drug-induced parkinsonism (DIP) and Parkinson's disease (PD) can be very challenging. Although PD and DIP to some extent display similar clinical symptoms, the underlying pathophysiologic mechanisms are entirely different. Given these differences in pathogenesis, and the diagnostic utility of BAER for detecting brainstem function, BAER may help to distinguish between PD and DIP. This study aimed to assess the accuracy and predictive values of BAER parameters in differentiating DIP from PD.

METHODS

We prospectively studied143 participants classified within three groups, including 50 controls, 57 PD, and 36 DIP. BAER was performed on all patients in the study. Patients in the DIP group were followed up for at least one year after discontinuation of the causative drug and examined for final diagnosis. We compared BAER latencies of the three groups and measured sensitivity, specificity, predictive values, likelihood ratios, and accuracy of BAER in diagnosing DIP.

RESULT

Waves V, I-V, and III-V latencies were significantly prolonged among the PD patients compared to the DIP and the control group; however, there were no significant differences in BAER latencies between the DIP and the control group. Waves V and I-V latencies revealed the highest accuracy (86% and 79%, respectively) in distinguishing DIP from PD with high negative predictive value(89% and 83%, respectively) as well as a high negative likelihood ratio (0.2and 0.3, respectively).

CONCLUSION

This study showed that waves V and I-V latencies are significantly prolonged in PD patients compared to those with DIP, consistent with the proposed mechanisms of neurodegeneration in PD, particularly in the midbrain and pons. Consequently, BAER could be used as a useful diagnostic tool for differentiating DIP from PD.

A comparison of prediction approaches for identifying prodromal Parkinson disease

Identifying people with Parkinson disease during the prodromal period, including via algorithms in administrative claims data, is an important research and clinical priority. We sought to improve upon an existing penalized logistic regression model, based on diagnosis and procedure codes, by adding prescription medication data or using machine learning. Using Medicare Part D beneficiaries age 66–90 from a population-based case-control study of incident Parkinson disease, we fit a penalized logistic regression both with and without Part D data. We also built a predictive algorithm using a random forest classifier for comparison. In a combined approach, we introduced the probability of Parkinson disease from the random forest, as a predictor in the penalized regression model. We calculated the receiver operator characteristic area under the curve (AUC) for each model. All models performed well, with AUCs ranging from 0.824 (simplest model) to 0.835 (combined approach). We conclude that medication data and random forests improve Parkinson disease prediction, but are not essential.

Cell-Type-Specific High Throughput Toxicity Testing in Human Midbrain Organoids

Toxicity testing is a crucial step in the development and approval of chemical compounds for human contact and consumption. However, existing model systems often fall short in their prediction of human toxicity in vivo because they may not sufficiently recapitulate human physiology. The complexity of three-dimensional (3D) human organ-like cell culture systems ("organoids") can generate potentially more relevant models of human physiology and disease, including toxicity predictions. However, so far, the inherent biological heterogeneity and cumbersome generation and analysis of organoids has rendered efficient, unbiased, high throughput evaluation of toxic effects in these systems challenging. Recent advances in both standardization and quantitative fluorescent imaging enabled us to dissect the toxicities of compound exposure to separate cellular subpopulations within human organoids at the single-cell level in a framework that is compatible with high throughput approaches. Screening a library of 84 compounds in standardized human automated midbrain organoids (AMOs) generated from two independent cell lines correctly recognized known nigrostriatal toxicants. This approach further identified the flame retardant 3,3',5,5'-tetrabromobisphenol A (TBBPA) as a selective toxicant for dopaminergic neurons in the context of human midbrain-like tissues for the first time. Results were verified with high reproducibility in more detailed dose-response experiments. Further, we demonstrate higher sensitivity in 3D AMOs than in 2D cultures to the known neurotoxic effects of the pesticide lindane. Overall, the automated nature of our workflow is freely scalable and demonstrates the feasibility of quantitatively assessing cell-type-specific toxicity in human organoids in vitro.

Exploring Movement Impairments in Patients With Parkinson's Disease Using the Microsoft Kinect Sensor: A Feasibility Study

Background: Current assessments of motor symptoms in Parkinson's disease are often limited to clinical rating scales. Objectives: To develop a computer application using the Microsoft Kinect sensor to assess performance-related bradykinesia. Methods: The developed application (Motorgame) was tested in patients with Parkinson's disease and healthy controls. Participants were assessed with the Movement Disorder Society Unified Parkinson's disease Rating Scale (MDS-UPDRS) and standardized clinical side effect rating scales, i.e., UKU Side Effect Rating Scale and Simpson-Angus Scale. Additionally, tests of information processing (Symbol Coding Task) and motor speed (Token Motor Task), together with a questionnaire, were applied. Results: Thirty patients with Parkinson's disease and 33 healthy controls were assessed. In the patient group, there was a statistically significant (p < 0.05) association between prolonged time of motor performance in the Motorgame and upper body rigidity and bradykinesia (MDS-UPDRS) with the strongest effects in the right hand (p < 0.001). In the entire group, prolonged time of motor performance was significantly associated with higher Simson-Angus scale rigidity score and higher UKU hypokinesia scores (p < 0.05). A shortened time of motor performance was significantly associated with higher scores on information processing (p < 0.05). Time of motor performance was not significantly associated with Token Motor Task, duration of illness, or hours of daily physical activity. The Motorgame was well-accepted. Conclusions: In the present feasibility study the Motorgame was able to detect common motor symptoms in Parkinson's disease in a statistically significant and clinically meaningful way, making it applicable for further testing in larger samples.

Amitriptyline interferes with autophagy-mediated clearance of protein aggregates via inhibiting autophagosome maturation in neuronal cells

Amitriptyline is a tricyclic antidepressant commonly prescribed for major depressive disorders, as well as depressive symptoms associated with various neurological disorders. A possible correlation between the use of tricyclic antidepressants and the occurrence of Parkinson's disease has been reported, but its underlying mechanism remains unknown. The accumulation of misfolded protein aggregates has been suggested to cause cellular toxicity and has been implicated in the common pathogenesis of neurodegenerative diseases. Here, we examined the effect of amitriptyline on protein clearance and its relevant mechanisms in neuronal cells. Amitriptyline exacerbated the accumulation of abnormal aggregates in both in vitro neuronal cells and in vivo mice brain by interfering with the (1) formation of aggresome-like aggregates and (2) autophagy-mediated clearance of aggregates. Amitriptyline upregulated LC3B-II, but LC3B-II levels did not increase further in the presence of NH₄Cl, which suggests that amitriptyline inhibited autophagic flux rather than autophagy induction. Amitriptyline interfered with the fusion of autophagosome and lysosome through the activation of PI3K/Akt/mTOR pathway and Beclin 1 acetylation, and regulated lysosome positioning by increasing the interaction between proteins Arl8, SKIP, and kinesin. To the best of our knowledge, we are the first to demonstrate that amitriptyline interferes with autophagic flux by regulating the autophagosome maturation during autophagy in neuronal cells. The present study could provide neurobiological clue for the possible correlation between the amitriptyline use and the risk of developing neurodegenerative diseases.

Trimetazidine Use and the Risk of Parkinsonism: A Nationwide Population-Based Study

An association between trimetazidine (TMZ), an anti-anginal drug, and parkinsonism has been reported in a number of studies. However, evidence from studies with long-term follow-up and better validity is lacking. We investigated the risk of TMZ-associated parkinsonism, specifically the incidence rate, cumulative dose–response relationship, and combined effects with other parkinsonism-inducing medications. This propensity score-matched retrospective cohort study was conducted using 14-year health insurance claims data in South Korea. The risk of parkinsonism was evaluated using multivariate Cox proportional hazard regression analysis, adjusted for comorbidities and concurrent medications. A total of 9712 TMZ users and 29,116 matched non-TMZ users were included. TMZ users had a significantly higher incidence rate of parkinsonism than non-TMZ users (9.34 vs. 6.71 per 1000 person-years; p < 0.0001). TMZ use significantly increased the risk of parkinsonism (adjusted hazard ratio = 1.38; 95% confidence interval = 1.26–1.51). Increased risks were observed with accumulated doses of TMZ, as well as concurrent use of other parkinsonism-inducing medications. The findings indicate that TMZ use significantly increases the risk of parkinsonism in the South Korean population. Closer monitoring should be considered for TMZ users, especially for those who are older, using TMZ at high cumulative doses and other parkinsonism-inducing medications.

Investigation of anti-Parkinson activity of dicyclomine

BACKGROUND

Parkinson's disease (PD) is a progressive neurodegenerative disorder. The major causative factors that progress the PD are age, genetic abnormalities, environmental factors and degeneration of dopamine neurons in substantia nigra. PD normally exerts a tonic inhibitory effect on striatal cholinergic interneurons. Anticholinergics act by normalizing the disequilibrium between striatal dopamine and acetylcholine-resulted reduction in tremors.

OBJECTIVE

This study sought to evaluate the anti-Parkinson potential of dicyclomine in haloperidol (HAL)- and paraquat (PQT)-induced Parkinsonism models in mice.

MATERIALS AND METHODS

Sixty albino mice were divided into six groups (n = 10) for each model. Group I: received distilled water 1 mL/kg, Group II: diseased group received HAL (1 mg/kg) for consecutive 21 days and PQT (2 mg/kg) every three days for three weeks, Group III: treated with sinemet (20 mg/kg), Group IV-VI: received 40, 80 and 160 mg/kg dose of dicyclomine, respectively, for consecutive 21 days. The effect of treatments on spontaneous locomotor activity and motor co-ordination was evaluated by using open field, rotarod, actophotometer and light and dark box tests. Cataleptic behavior was estimated by the block method and triple horizontal bar apparatus. Biochemical markers of oxidative stress and levels of neurotransmitters were estimated.

RESULTS

Findings from this study showed that dicyclomine at highest dose level of 160 mg/kg prevented HAL- and PQT-induced PD through enhancement of antioxidant defense system.

CONCLUSION

The study concluded that dicyclomine could be the potential drug in the management of Parkinsonism.

Shared functional neural substrates in Parkinson's disease and drug-induced parkinsonism: association with dopaminergic depletion

While drug-induced parkinsonism (DIP) is mainly caused by blockage of the dopaminergic pathway, multiple neurotransmitter systems besides the dopaminergic system are involved in Parkinson’s disease (PD). Therefore, alterations found in both DIP and PD might be manifestations of dopaminergic dysfunction. To prove this hypothesis, we aimed to define the areas commonly involved in DIP and PD and determine whether the overlapping areas were associated with the dopaminergic system. 68 PD patients, 69 DIP patients and 70 age-and sex-matched controls underwent resting-state functional MRI (rsfMRI). Regional homogeneity (ReHo), amplitude of low-frequency fluctuation (ALFF) and fractional ALFF were calculated and compared. Afterwards, we compared mean rsfMRI values extracted from the overlapping areas with uptake quantitatively measured on dopamine transporter (DAT) images and neuropsychological test results. Compared to the controls, both PD and DIP patients revealed altered rsfMRI values in the right insular cortex, right temporo-occipital cortex, and cerebellum. Among them, decreased ALFF in the right insular cortex and decreased ReHo in the right occipital cortex were correlated with decreased DAT uptake in the caudate as well as executive, visuospatial, and language function. Increased ReHo in the cerebellum was also correlated with decrease DAT uptake in the posterior and ventral anterior putamen, but not with cognitive function. In conclusion, the insular cortex, occipital cortex, and cerebellum were commonly affected in both PD and DIP patients and might be associated with altered dopaminergic modulation.

Buspirone-associated Movement Disorder: A Literature Review

Buspirone (BUS) belongs to the azapirone chemical class. The aim of this literature review is to evaluate the clinical epidemiological profile, pathological mechanisms, and management of BUS-associated movement disorders (MD). Relevant reports in six databases were identified and assessed by two reviewers without language restriction. A total of 25 reports containing 65 cases were assessed. The MD associated with BUS were: dyskinesia in 14 cases, 10 of akathisia, 8 of myoclonus, 6 of Parkinsonism, and 6 of dystonia. The cases not clearly defined were 7 tension, 14 incoordination, and the undefined number of dyskinesia, tics, and Parkinsonism. The mean age was 45.23 years (range: 15-74). The male was the predominant sex in 60.86% and the most common BUS-indication was anxiety disorder. The mean BUS-dose was 42.16 mg (range: 5-100). The time from the beginning of BUS administration to the MD onset was one month or less in 76%. The time from BUS withdrawal to complete recovery was within one month in 87.5%. The most common management was BUS withdrawal. In 16 patients the follow-up was reported: 14 had a full recovery, but in two (1 dyskinesia + 1 dystonia) the symptoms continued after the BUS withdrawal. MD associated with BUS were scarcely reported in the literature. Moreover, in the majority of cases, no clear description of the clinical profile, neurological examination, or the time data of the movement disorder onset and recovery were given.

Parkinsonism: A Rare Adverse Effect of Valproic Acid

Valproic acid (VPA) is an anti-epileptic drug (AED) used as a first-choice agent for most forms of epilepsy. It is used in the treatment of manic episodes, bipolar disorder, migraine prevention, and impulse control. Hence it is one of the most commonly prescribed drugs by physicians nowadays. VPA acts by increasing gama amino butyric acid (GABA) levels, and also reduces neuronal activation by blocking voltage-gated sodium, potassium, and calcium channels. VPA has various adverse effects like thrombocytopenia, hyperammonemia, teratogenicity causing spina bifida in newborns when exposed in utero. The focus of this review is to research one such easily overlooked adverse effect of VPA, which is VPA-induced Parkinsonism. We carried out a review of literature and gathered all comprehensive peer-reviewed articles from PubMed. The data for this research were collected ethically and legally after a thorough examination of the literature. Data obtained from the studies have suggested that Parkinsonism is an adverse effect of VPA. Chronic usage of VPA causes Parkinsonism. It occurs equally in males and females, more common in older people usually above the age of 55 years and not dose-dependent. According to the data obtained, all patients who developed Parkinsonism had serum levels in the therapeutic range (50-100 mcg/mL). Thus the chronic intake of maintenance dose of VPA seems to be the leading cause. The symptoms usually improve over a few weeks and fully resolve in a few months after stopping the drug. When the patient's symptoms do not improve, it means VPA has unmasked the underlying potential for developing Parkinson's disease. Such patients benefit from levodopa therapy. However, the mechanism of how VPA causes Parkinsonism remains unknown. Based on the articles reviewed, we hypothesize that VPA's mechanism of neuronal inactivation by blocking membrane channels across the neuronal membrane, primarily when used chronically could be the mechanism by which it causes Parkinsonism. VPA causes down regulation of sodium and potassium channels on neuronal membrane in order to stop the neurons from firing. Thereby a decrease in action potential across the neurons causes a temporary physiological inactivation of the neuron. When multiple neurons are inactivated in the basal ganglia of the brain, the patient develops symptoms of Parkinsonism. As the neurons are only temporarily inactivated physiologically, when the drug is stopped the membrane receptors are reactivated on the neuronal membranes. This leads to neuronal activation and neuronal membrane potential becomes the same as before. The above mechanism clarifies why the symptoms settle down when the medication is stopped.

Trimetazidine-Induced Parkinsonism: A Systematic Review

Importance: Trimetazidine (TMZ) is a medication given to patients with stable coronary artery disease. While it is reportedly well-tolerated, there are increasing numbers of reports of adverse events such as parkinsonism.

Objectives: The purpose of this study was to systematically review the currently available literature on TMZ-induced parkinsonism.

Evidence Review: A search of Scopus, MEDLINE, EMBASE, the Cochrane Library, the Health Technology Assessment Database, PubMed, Science Direct, and Google Scholar was conducted on or before November 7, 2019. The literature search included cohort studies, prospective and/or retrospective studies, meta-analysis, and other systematic reviews published as an original article, including abstracts and full texts. We included patients taking TMZ who developed one or more of the parkinsonian symptoms of bradykinesia, tremors, rigidity, and postural instability, where these symptoms improved after withdrawal of the said medication.

Findings: There are currently five studies on TMZ use and associated parkinsonism. The literature included two case reports, one case series, and one retrospective and one prospective study. We found no results from randomized clinical trials. Overall, 88 patients developed TMZ-induced parkinsonism. Regression of parkinsonism was reported in all of the participants after withdrawal of TMZ. A total of 49 patients (55.7%) had complete regression of symptoms, while 39 patients (44.3%) had significant reduction of symptoms. The duration between TMZ (dose, 60–80 mg/day) intake and onset of symptoms ranged from 4 months to 20 years. The most commonly reported extrapyramidal symptoms were akinesia, rigidity, postural disturbances, and gait disorders, which were usually mild and symmetric.

Conclusions and Relevance: The current literature suggests that TMZ can induce parkinsonism that is reversible with drug withdrawal. It is warranted to examine patients, especially the elderly, on TMZ for parkinsonian symptoms and those with pre-existing neurodegenerative diseases. Further studies are needed to assess the risk-benefit ratio of this drug, especially in the elderly age group.

Symptomatic Characteristics of Parkinson's Disease Induced by Neuroleptic Drugs, Based on a Functional Neuroimaging Diagnosis

Objective When patients take neuroleptics, the distinction between Parkinson's disease (PD) and drug-induced parkinsonism (DIP) based solely on clinical features can become difficult. At present, ¹²³I-FP-CIT SPECT (DAT-SPECT) and ¹²³I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy are widely used to supplement the differential diagnosis of parkinsonism. This study assessed the clinical symptoms and neurological findings in the patients suspected of having DIP based on DAT-SPECT findings. Methods Twenty-three patients (11 men, 12 women, age: 52-81 years old) presenting with DIP were recruited. All patients underwent neurological examinations, including brain magnetic resonance imaging and DAT-SPECT. Patients who showed abnormal DAT-SPECT results underwent MIBG myocardial scintigraphy. Results Eleven patients showed a reduction in the ligand uptake on DAT-SPECT (DAT-positive group), and nine of these patients showed a low delayed heart-to-mediastinum (H/M) ratio on MIBG myocardial scintigraphy. The remaining 12 patients showed normal results on DAT-SPECT (DAT-negative group). All patients in the DAT-positive group had asymmetric motor symptoms, whereas only 4 in the DAT-negative group exhibited this clinical feature (p=0.001). A detailed medical history showed that 7 of the 11 patients in the DAT-positive group had prodromal symptoms for PD. However, only 1 patient in the DAT-negative group exhibited these symptoms (p= 0.009). Although two patients in the DAT-negative group showed poor improvement, they showed a normal H/M ratio on MIBG and no response to levodopa. Conclusion The patients in the DAT-positive group might have prodromal symptoms that were worsened by neuroleptic drugs. The results of detailed history-taking and neurological findings seem to indicate cases of compromised dopaminergic transmission before the administration of neuroleptic drugs.

Drug-Induced Parkinsonism Manifesting as Gait Freezing in a Patient With Traumatic Brain Injury: A Case Report

BACKGROUND

Among the neuropsychiatric complications commonly induced by traumatic brain injury (TBI), behavioral disorders, such as agitation and aggression, can hinder neurological recovery and deteriorate rehabilitation outcomes. Pharmacological treatment for behavioral disorders might be beneficial but could lead to drug-induced parkinsonism. We report a case of a patient with drug-induced parkinsonism manifested as freezing of gait after TBI, which improved with the cessation of the offending drugs and comprehensive rehabilitation.

CASE PRESENTATION

A 35-year-old male patient left with a TBI after a car accident was referred to our hospital. He had been on many neuropsychiatric medications, including atypical antipsychotics, for his agitated behaviors. He could walk independently but showed freezing of gait at the initiation of his gait, when turning to the side, when reaching his destination, and passing through narrow corridors. Under the impression of drug-induced parkinsonism, we gradually tapered the patient off his neuropsychiatric medications. He also underwent comprehensive rehabilitation, including gait training under visual and auditory cues and balance training. Five weeks after admission to the hospital, the patient's freezing of gait improved, with disappearance of his hesitation at gait initiation and a decreased freezing duration while turning around.

CONCLUSIONS

This is a rare report of drug-induced parkinsonism manifested as freezing of gait, which showed improvement after discontinuation of the causative drugs and subsequent rehabilitation.

Parkinsonism associated with gabapentinoid drugs: A pharmacoepidemiologic study

BACKGROUND

Use of gabapentinoids is increasing. Following recent case reports, we investigated a putative risk of parkinsonism with pregabalin or gabapentin.

METHODS

A disproportionality analysis of 5,653,547 individual case safety reports in the World Health Organization individual case safety report database, VigiBase, compared all patients with parkinsonism who were receiving gabapentinoids with other patients. Results are shown as reporting odds ratios and the information component, an indicator of disproportionate Bayesian reporting. Sensitivity analyses included comparisons with drugs used for similar indications (amitriptyline, duloxetine) and exclusion of drugs that induce parkinsonism.

RESULTS

Among 5,653,547 reports, 4925 parkinsonism reports were found with pregabalin and 4881 with gabapentin. Gabapentin and pregabalin were associated with increased reporting odds ratio (2.16 [2.10-2.23], 2.43 [2.36-2.50]). Similar trends were found using information components after excluding drugs that induce parkinsonism and for pregabalin compared with amitriptyline or duloxetine.

CONCLUSIONS

This study found that gabapentinoids (particularly pregabalin) can be associated with parkinsonism. © 2019 International Parkinson and Movement Disorder Society.

Prevalence and incidence of Parkinson's disease and drug-induced parkinsonism in Korea

Background

Parkinson’s disease (PD) and drug-induced parkinsonism (DIP) are the major diseases of parkinsonism. To better understand parkinsonism, we aimed to assess the prevalence and incidence of PD and DIP in Korea from 2012 to 2015.

Methods

We used the Health Insurance Review and Assessment Service database, which covers the entire population in Korea. We used claims during 2011–2015 to assess epidemiology of PD and DIP during 2012–2015. Retrospective cross-sectional study design was employed to assess prevalence, whereas retrospective cohort study design was used to determine incidence. Patients with at least one claim with ICD-10 G20 and who received antiparkinsonian drugs for at least 60 days were classified as having PD. We excluded patients with antiparkinsonian drugs that can be used for indications other than PD. Patients with at least one claim with ICD-10 G211 or G251 during the prescription period of drugs that are frequently related with DIP were classified as having DIP. Incident cases had a disease-free period of 1 year before diagnosis. To evaluate the significance of changes in the prevalence or incidence over time, Poisson regression was used to determine p for trend.

Results

The prevalence of PD increased from 156.9 per 100,000 persons in 2012 to 181.3 per 100,000 persons in 2015 (p for trend< 0.0001). The incidence of PD decreased steadily from 35.4 per 100,000 person-years in 2012 to 33.3 per 100,000 person-years in 2015 (p for trend< 0.0001). The prevalence of DIP increased from 7.3 per 100,000 persons in 2012 to 15.4 per 100,000 persons in 2015 (p for trend< 0.0001) and the incidence of DIP increased from 7.1 per 100,000 person-years in 2012 to 13.9 per 100,000 person-years in 2015 (p for trend< 0.0001).

Conclusions

Our study suggests that the incidence of PD has gradually decreased whereas, the incidence of DIP increased from 2012 to 2015. Further studies are warranted to examine possible causes of increased DIP incidence in order to develop management strategy for parkinsonism.

Metoclopramide as a prokinetic agent for diabetic gastroparesis: revisiting the risk of Parkinsonism

Background:

Metoclopramide is used to relieve gastrointestinal symptoms, however, it could cause adverse reactions of motor disorders. The aim of this study was to investigate whether metoclopramide treatment has a duration–response or dose–response effect and to estimate the risk of developing Parkinsonism following different and specific durations of treatment.

Methods:

A cohort study of newly diagnosed type 2 diabetes mellitus in 45- to 79-year-old patients, between 1999 and 2008, was selected using the Longitudinal Health Insurance Database 2005. A nested case–control study was conducted in the diabetes cohort in which all incident cases of Parkinsonism were identified. We randomly matched each case with up to 10 controls from the risk set. Conditional logistic regression was utilized to estimate odds ratio of Parkinsonism associated with metoclopramide use.

Results:

A total of 34,685 patients with diabetes were assembled as the cohort, and 541 incident Parkinsonism cases were identified. There were duration–response and dose–response effects on the risk of developing Parkinsonism. Compared with never-use patients, the adjusted odds ratios (ORs) of continuing therapy for 0–1 month, 1–2 months, 2–3 months, 3–5 months, and more than 5 months were 1.17 [95% confidence interval (CI) 0.93–1.45], 1.44 (95% CI 1.04–2.00), 1.74 (95% CI 1.14–2.65), 1.90 (95% CI 1.23–2.93), and 2.17 (95% CI 1.50–3.12), respectively.

Conclusions:

With metoclopramide treatment, regardless of less or more than 3 months of use, the risk of developing Parkinsonism in patients with newly diagnosed diabetes escalated with the duration of therapy. Therefore, we recommend close monitoring for the development of Parkinsonism in patients treated with metoclopramide, particularly (but not limited to) those with prolonged exposure.

Association Between Drug Exposure and Occurrence of Parkinsonism in Korea: A Population-Based Case-Control Study

Background: Although drug-induced parkinsonism is reversible in most cases, some patients can suffer from persistent/recurrent symptoms. Therefore, prevention is the most efficient way to manage drug-induced parkinsonism. However, there is a paucity of studies exploring the relationship between parkinsonism and drug exposure. Objective: To examine the association between drug exposure and the risk of parkinsonism using Korean population-based data. Methods: We conducted a matched case-control study using the National Health Insurance Service-National Sample Cohort database. Cases and controls were defined as individuals with and without parkinsonism, respectively, between 2007 and 2013. Cases and controls were matched for sex, age group, income, type of insurance, and Charlson comorbidity index. Drug exposures, including propulsives, antipsychotics, and flunarizine, were identified at 1 year before the first date of parkinsonism and stratified by recency and cumulative dose. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% CIs. Results: We identified 5496 cases and 5496 controls. ORs for current use group of propulsives, antipsychotics, and flunarizine compared with those of the never use group were 2.812 (95% CI = 2.466-3.206), 3.009 (95% CI = 1.667-5.431), and 4.950 (95% CI = 2.711-9.037), respectively. ORs were greater in those more recently exposed and those exposed to higher cumulative doses. Conclusion and Relevance: At the population level, use of propulsives, antipsychotics, and flunarizine had a significant association with the increased risk of parkinsonism, depending on recency and cumulative dose. Drugs associated with parkinsonism should be used with careful monitoring to prevent drug-induced parkinsonism.

An Unusual Cause of Camptocormia

Background

Camptocormia is defined as forward flexion of the spine that manifests during walking and standing and disappears in recumbent position. The various etiologies include idiopathic Parkinson’s disease, multiple system atrophy, myopathies, degenerative joint disease, and drugs.

Case Report

A 67-year-old diabetic female presented with bradykinesia and camptocormia that started 1 year prior to presentation. Evaluation revealed levosulpiride, a dopamine receptor blocker commonly used for dyspepsia, to be the culprit.

Discussion

It is well known that dopamine receptor blockers cause parkinsonism and tardive syndromes. We report a rare and unusual presentation of camptocormia attributed to this commonly used gastrointestinal drug in the Asian population.

Anticholinergic and sedative medication use in older community-dwelling people: A national population study in the Netherlands

Purpose

To identify the proportion of older adults with a high anticholinergic/sedative load and to identify patient subgroups based on type of central nervous system (CNS)‐active medication used.

Methods

A cross‐sectional study of a nationwide sample of patients with anticholinergic/sedative medications dispensed by 1779 community pharmacies in the Netherlands (90% of all community pharmacies) in November 2016 was conducted. Patients aged older than 65 years with a high anticholinergic/sedative load defined as having a drug burden index (DBI) greater than 1 were included. Proportion of patients with a high anticholinergic/sedative load was calculated by dividing the number of individuals in our study population by the 2.4 million older patients using medications dispensed from study pharmacies. Patient subgroups based on type of CNS‐active medications used were identified with latent class analysis.

Results

Overall, 8.7% (209 472 individuals) of older adults using medications had a DBI greater than 1. Latent class analysis identified four patient subgroups (classes) based on the following types of CNS‐active medications used: “combined psycholeptic/psychoanaleptic medication” (class 1, 57.9%), “analgesics” (class 2, 17.9%), “antiepileptic medication” (class 3, 17.8%), and “anti‐Parkinson medication” (class 4, 6.3%).

Conclusions

A large proportion of older adults in the Netherlands had a high anticholinergic/sedative load. Four distinct subgroups using specific CNS‐active medication were identified. Interventions aiming at reducing the overall anticholinergic/sedative load should be tailored to these subgroups.

NADPH ameliorates MPTP-induced dopaminergic neurodegeneration through inhibiting p38MAPK activation

Parkinson's disease (PD) is the second most common neurodegenerative disorder characterized by the selective loss of dopaminergic neurons in substantia nigra pars compacta (SNpc). Although the pathogenic mechanism underlying PD remains largely unknown, decreased nigral glutathione (GSH) in postmortem brains of PD patients supports the presence of oxidative stress in PD. We found that Nicotinamide adenine dinucleotide phosphate (NADPH), which is important for maintaining the level of GSH, protected dopaminergic (DA) neurons from neurotoxicity of MPTP/MPP⁺. In the present study, NADPH prevented DA neurons from MPTP toxicity with increased GSH and decreased reactive oxygen species (ROS) levels in the ventral midbrain of mice, and improved motor activity. Our present results demonstrated that NADPH inhibited the phosphorylation of p38MAPK, decreased the level of TP53 protein, and inhibited TP53 nuclear translocation in DA neurons of SNpc and in MES23.5 cells. Furthermore, NADPH decreased the protein level of TP53 target gene, Bax, cleavage of PARP, and nuclei condensation. Taken together, NADPH abrogated MPTP-induced p38MAPK phosphorylation, TP53 nuclear translocation, and Bax induction, and finally, MPTP/MPP⁺-induced apoptosis of DA neurons. This study suggests that NADPH may be a novel therapeutic candidate for PD.

Clinical features of drug-induced Parkinsonism

Drug-induced Parkinsonism is often reversible after withdrawal of the causative drug. Its clinical course, however, is not well understood, as the majority of cases are caused by drugs prescribed by departments outside of neurology. We reviewed 21 cases of drug-induced parkinsonism for several factors, including age, sex, causative drug and reason for prescription, department by which it was prescribed, and outcome. The age at onset ranged from 40 to 87 years, with an average Hoehn and Yahr Scale score of 4, indicating severe disability. Sulpiride was the most commonly observed causative drug (71.4%). All causative drugs were prescribed in non-neurological departments and over one half were prescribed in non-psychiatric departments; most were prescribed to treat depression or abdominal discomfort. Ten patients (48%) were previously diagnosed with a neuromuscular disease, including cerebrovascular diseases and Parkinson's disease. Recovery was observed in 15 cases (71%) after withdrawal of the causative drug, but lingering symptoms were observed in the remaining cases. It is suggested that physicians should be more cautious of Parkinsonian side effects when prescribing such drugs.

Tramadol-induced parkinsonism: a case report of a 75-year-old woman

Adverse drug reaction (ADR) is a form of unwanted reaction and is the crucial reason for illness and death. Tramadol-induced parkinsonism is a kind of ADR that occurs after the repeated intake of tramadol. Long-term exposure to tramadol has been known to induce tremor and alter the functioning of dopamine. This case report introduces a 75-year-old woman diagnosed with tramadol-induced parkinsonism due to the administration of tramadol for the treatment of post-operated (breast cancer) acute onset of severe pain on the left side of the chest. The assessment of the offending drug was carried out via Naranjo probability scale. A score of 6 was reported for this patient, defining tramadol as a probable cause of this reaction. For the management of the drug-induced parkinsonism, levodopa/carbidopa was prescribed and the symptoms related to parkinsonism resolved within a week. The age of the patient and the female gender is considered to be the main risk factor for the occurrence of such reaction. This case report is an attempt to spread awareness about the negative consequences of long-term use of tramadol in old patients. Thus, the medical practitioners must be very careful while administering tramadol to the old aged population.

Cross-sectional examination of extrapyramidal side effects in a specialist palliative care inpatient unit

OBJECTIVES

Extrapyramidal side effects (EPSEs) are serious potentially reversible side effects of antipsychotic and other medications that can cause distress for patients. A core principle of palliative care involves optimising quality of life. If side effects of medications are burdensome, it is imperative that we address this issue. The aim of the study was to determine and describe the burden of EPSEs in a specialist inpatient unit.

METHODS

Consenting patients who met inclusion criteria were assessed for EPSE with two validated screening tests, the Modified Simpson-Angus Scale (MSAS) and Barnes Akathisia Rating Scale (BARS). Additional demographic data were collected including medications associated with EPSE, previous history of EPSE and known risk factors that may predispose a patient to EPSE.

RESULTS

43% inpatients met inclusion criteria. At least 66% of patients were taking regular medications associated with EPSE. Of those, 25% were taking ≥2 medications associated with EPSE. The MSAS revealed 50% scored <3, 44% scored 3-5% and 6% scored 6-11. Seven patients had at least one 'not rateable score'. In the BARS (sitting±standing), 94% scored 0/5 and 6% scored 1/5. 12.5% of participants were able to stand for 2 min to complete the BARS.

CONCLUSIONS

50% screened positive for EPSE. The complete BARS was unsuitable for most participants. The MSAS, while allowing a not rateable score, may underestimate EPSE. The frailty of an inpatient unit population impacts on applicability of screening tools and may therefore underestimate the burden of the problem in this population. Development of a population-specific screening tool warrants further investigation.

Acute dopamine receptor blockade in substantia nigra pars reticulata: a possible model for drug-induced Parkinsonism

Dopamine (DA) depletion modifies the firing pattern of neurons in the substantia nigra pars reticulata (SNr), shifting their mostly tonic firing toward irregularity and bursting, traits of pathological firing underlying rigidity and postural instability in Parkinson's disease (PD) patients and animal models of Parkinsonism (PS). Drug-induced Parkinsonism (DIP) represents 20-40% of clinical cases of PS, becoming a problem for differential diagnosis, and is still not well studied with physiological tools. It may co-occur with tardive dyskinesia. Here we use in vitro slice preparations including the SNr to observe drug-induced pathological firing by using drugs that most likely produce it, DA-receptor antagonists (SCH23390 plus sulpiride), to compare with firing patterns found in DA-depleted tissue. The hypothesis is that SNr firing would be similar under both conditions, a prerequisite to the proposal of a similar preparation to test other DIP-producing drugs. Firing was analyzed with three complementary metrics, showing similarities between DA depletion and acute DA-receptor blockade. Moreover, blockade of either nonselective cationic channels or Ca_v3 T-type calcium channels hyperpolarized the membrane and abolished bursting and irregular firing, silencing SNr neurons in both conditions. Therefore, currents generating firing in control conditions are in part responsible for pathological firing. Haloperidol, a DIP-producing drug, reproduced DA-receptor antagonist firing modifications. Since acute DA-receptor blockade induces SNr neuron firing similar to that found in the 6-hydroxydopamine model of PS, output basal ganglia neurons may play a role in generating DIP. Therefore, this study opens the way to test other DIP-producing drugs. NEW & NOTEWORTHY Dopamine (DA) depletion enhances substantia nigra pars reticulata (SNr) neuron bursting and irregular firing, hallmarks of Parkinsonism. Several drugs, including antipsychotics, antidepressants, and calcium channel antagonists, among others, produce drug-induced Parkinsonism. Here we show the first comparison between SNr neuron firing after DA depletion vs. firing found after acute blockade of DA receptors. It was found that firing in both conditions is similar, implying that pathological SNr neuron firing is also a physiological correlate of drug-induced Parkinsonism.

Parkinson Disease

Parkinson disease is a common neurodegenerative disorder that causes progressive motor and nonmotor disability. It is diagnosed clinically and requires a detailed history and neurologic examination to exclude alternative diagnoses. Although disease-modifying therapies do not exist for Parkinson disease, effective symptomatic therapies, including dopaminergic medications and surgery, allow patients to maintain good quality of life for many years. Nonmotor symptoms, including mood, cognitive, sleep, autonomic, and gastrointestinal symptoms, should be managed by a multidisciplinary team of clinicians. Recent advances include new diagnostic criteria from the Movement Disorder Society and the addition of new symptomatic therapies for treating motor complications and nonmotor symptoms in advanced disease.

High exposure compared with standard exposure to metoclopramide associated with a higher risk of parkinsonism: a nationwide population-based cohort study

AIMS

We conducted a cohort study utilizing a nationwide health insurance database to assess the European Medicines Agency's restrictions on using metoclopramide and its association with the risk of parkinsonism.

METHODS

New oral metoclopramide users aged ≥20 years, and age- and gender-matched non-users were recruited between 2001 and 2011. Users were divided into high-exposure (dose >30 mg day^-1 and/or duration >5 days) and standard-exposure (dose ≤30 mg day^-1 and duration ≤5 days) groups. The adjusted hazard ratio (aHR) with 95% confidence interval (CI) estimated the risk of parkinsonism.

RESULTS

During a 1-year period, 122 of 218 931 (0.06%) users of metoclopramide vs. 56 of 218 931 (0.03%) non-users developed parkinsonism (P < 0.001). Among the 122 cases of parkinsonism in users, 64 (0.04%) were from 168 566 standard-exposure users and 58 (0.12%) from 50 365 high-exposure users. Compared with non-users, the risk of parkinsonism was higher in users (aHR 2.16; 95% CI 1.54, 3.02), including standard-exposure (aHR 1.73; 95% CI 1.11, 2.70), and high-exposure (aHR 3.15; 95% CI 1.78, 5.57) users. High-exposure users had a higher risk of parkinsonism than standard-exposure users (aHR 1.83; 95% CI 1.28, 2.63). Within the high-exposure group, 45 233 of 50 365 (89.81%) users and 55 of 58 (94.83%) parkinsonism were from long-duration exposure; 5 132 of 50 365 (10.19%) users and 3 of 58 (5.17%) parkinsonism were from high-dose exposure and long-duration + high-dose exposure.

CONCLUSIONS

The risk of parkinsonism in metoclopramide users, although extremely low (0.06%), is 2.16-fold greater than in non-users. High-exposure users have a 1.83-fold higher risk than standard-exposure users. As users in high-exposure group had a higher risk of parkinsonism than in standard-exposure group, and the majority of users and parkinsonism in high-exposure group were from long-duration exposure; thus, physician are advised to avoid prescribing metoclopramide for >5 days, even if the daily dose is ≤30 mg.

Typical features of Parkinson disease and diagnostic challenges with microdeletion 22q11.2

OBJECTIVE

To delineate the natural history, diagnosis, and treatment response of Parkinson disease (PD) in individuals with 22q11.2 deletion syndrome (22q11.2DS), and to determine if these patients differ from those with idiopathic PD.

METHODS

In this international observational study, we characterized the clinical and neuroimaging features of 45 individuals with 22q11.2DS and PD (mean follow-up 7.5 ± 4.1 years).

RESULTS

22q11.2DS PD had a typical male excess (32 male, 71.1%), presentation and progression of hallmark motor symptoms, reduced striatal dopamine transporter binding with molecular imaging, and initial positive response to levodopa (93.3%). Mean age at motor symptom onset was relatively young (39.5 ± 8.5 years); 71.4% of cases had early-onset PD (<45 years). Despite having a similar age at onset, the diagnosis of PD was delayed in patients with a history of antipsychotic treatment compared with antipsychotic-naive patients (median 5 vs 1 year, p = 0.001). Preexisting psychotic disorders (24.5%) and mood or anxiety disorders (31.1%) were common, as were early dystonia (19.4%) and a history of seizures (33.3%).

CONCLUSIONS

Major clinical characteristics and response to standard treatments appear comparable in 22q11.2DS-associated PD to those in idiopathic PD, although the average age at onset is earlier. Importantly, treatment of preexisting psychotic illness may delay diagnosis of PD in 22q11.DS patients. An index of suspicion and vigilance for complex comorbidity may assist in identifying patients to prioritize for genetic testing.

Methamphetamine use and future risk for Parkinson's disease: Evidence and clinical implications

BACKGROUND

Methamphetamine use has been posited to be a risk factor for the development of Parkinson's disease (PD) and parkinsonism. The clinical implications of a potential association between methamphetamine use and PD are considered.

METHODS

A review of methamphetamine and PD and parkinsonism was conducted, including evidence from animal models, clinical and population studies.

RESULTS

There is biological plausibility to a link between methamphetamine use and PD. Though clinical and epidemiological evidence in this area is scant, a number of studies suggest that methamphetamine is associated with a moderately increased risk of PD and parkinsonism, and may also lead to premature onset of PD. The long lag time between exposure to methamphetamine and onset of PD, the potential for recovery from neurotoxic effects, and tobacco smoking each may attenuate the association. Individual and drug use characteristics that may modulate a user's risk remain poorly understood.

CONCLUSIONS

The use of methamphetamine may be an initiating event in the development of PD and parkinsonism, in addition to other risk factors that a given individual may hold. Clinicians should be vigilant to signs of prodromal and emerging PD among methamphetamine users. In individuals with premature onset illness, information on current or prior exposure to methamphetamine should be sought.

Neuroimaging in Parkinson's disease: focus on substantia nigra and nigro-striatal projection

PURPOSE OF REVIEW

The diagnosis of Parkinson disease is based on clinical features; however, unmet need is an imaging signature for Parkinson disease and the early differential diagnosis with atypical parkinsonisms. A summary of the molecular imaging and MRI recent evidences for Parkinson disease diagnosis will be presented in this review.

RECENT FINDINGS

The nigro-striatal dysfunction explored by dopamine transporter imaging is not a mandatory diagnostic criterion for Parkinson disease, recent evidence supported its utility as in-vivo proof of degenerative parkinsonisms, and there might be compensatory mechanisms leading to an early overestimation. The visualization of abnormalities in substantia nigra by MRI has been recently described as sensitive and specific tool for Parkinson disease diagnosis, even in preclinical conditions, whereas it is not useful for distinguishing between Parkinson disease and atypical parkinsonisms. The relationship between the nigral anatomical changes, evaluated as structural alterations or neuromelanin signal decrease and the dopaminergic nigro-striatal function needs to be further clarified.

SUMMARY

With the hopeful advent of potential neuroprotective drugs for PD, it is crucial to have imaging measures that are able to detect at risk subjects. Moreover it is desirable to increase the knowledge about which measure better predicts the probability and the time of clinical conversion to PD.