Anticholinergics May Carry Significant Cognitive and Gait Burden in Parkinson's Disease

Cholinergic basal forebrain system degeneration underlies postural instability/gait difficulty and attention impairment in Parkinson's disease

BACKGROUND AND PURPOSE

The specific pathophysiological mechanisms underlying postural instability/gait difficulty (PIGD) and cognitive function in Parkinson's disease (PD) remain unclear. Both postural and gait control, as well as cognitive function, are associated with the cholinergic basal forebrain (cBF) system.

METHODS

A total of 84 PD patients and 82 normal controls were enrolled. Each participant underwent motor and cognitive assessments. Diffusion tensor imaging was used to detect structural abnormalities in the cBF system. The cBF was segmented using FreeSurfer, and its fiber tract was traced using probabilistic tractography. To provide information on extracellular water accumulation, free-water fraction (FWf) was quantified. FWf in the cBF and its fiber tract, as well as cortical projection density, were extracted for statistical analyses.

RESULTS

Patients had significantly higher FWf in the cBF (p < 0.001) and fiber tract (p = 0.021) than normal controls, as well as significantly lower cBF projection in the occipital (p < 0.001), parietal (p < 0.001) and prefrontal cortex (p = 0.005). In patients, a higher FWf in the cBF correlated with worse PIGD score (r = 0.306, p = 0.006) and longer Trail Making Test A time (r = 0.303, p = 0.007). Attentional function (Trail Making Test A) partially mediated the association between FWf in the cBF and PIGD score (indirect effect, a*b = 0.071; total effect, c = 0.256; p = 0.006).

CONCLUSIONS

Our findings suggest that degeneration of the cBF system in PD, from the cBF to its fiber tract and cortical projection, plays an important role in cognitive-motor interaction.

Recommendations for a paradigm shift in approach to increase the recognition and treatment of sialorrhea in Parkinson's disease

Sialorrhea, or drooling, is defined as excessive saliva accumulation and unwanted loss of saliva from the mouth or over the tongue and into the pharynx. It constitutes one of the most frequent and bothersome complaints of patients with Parkinson's disease (PD), affecting up to 84% of them. Sialorrhea is a distressing and challenging condition that may result in social isolation, embarrassment, depression, skin infections, poor oral health, and aspiration pneumonia. To better understand the burden of sialorrhea on patients with PD, Parkinson's Europe carried out a worldwide patient survey which showed that sialorrhea remains an underrecognized and undertreated issue in patients with PD. This is especially problematic because effective therapeutic options are available. This article presents the results of the Parkinson's Europe Sialorrhea Survey, which were considered by a multidisciplinary panel of experts to provide recommendations for improving the awareness, diagnosis, management, and treatment of sialorrhea in patients with PD. A shift in the treatment paradigm for sialorrhea in patients with PD is emerging. It is essential to better educate patients, family members, caregivers, and healthcare professionals about sialorrhea; to engage all those involved to actively discuss sialorrhea and measure its impact on quality of life; and to recognize the role of botulinum toxin and speech and language therapy as first-line therapies.

Predicting Ambulatory Capacity in Parkinson's Disease to Analyze Progression, Biomarkers, and Trial Design

BACKGROUND

In Parkinson's disease (PD), gait and balance is impaired, relatively resistant to available treatment and associated with falls and disability. Predictive models of ambulatory progression could enhance understanding of gait/balance disturbances and aid in trial design.

OBJECTIVES

To predict trajectories of ambulatory abilities from baseline clinical data in early PD, relate trajectories to clinical milestones, compare biomarkers, and evaluate trajectories for enrichment of clinical trials.

METHODS

Data from two multicenter, longitudinal, observational studies were used for model training (Tracking Parkinson's, n = 1598) and external testing (Parkinson's Progression Markers Initiative, n = 407). Models were trained and validated to predict individuals as having a "Progressive" or "Stable" trajectory based on changes of ambulatory capacity scores from the Movement Disorders Society Unified Parkinson's Disease Rating Scale parts II and III. Survival analyses compared time-to-clinical milestones and trial outcomes between predicted trajectories.

RESULTS

On external evaluation, a support vector machine model predicted Progressive trajectories using baseline clinical data with an accuracy, weighted-F1 (proportionally weighted harmonic mean of precision and sensitivity), and sensitivity/specificity of 0.735, 0.799, and 0.688/0.739, respectively. Over 4 years, the predicted Progressive trajectory was more likely to experience impaired balance, loss of independence, impaired function and cognition. Baseline dopamine transporter imaging and select biomarkers of neurodegeneration were significantly different between predicted trajectory groups. For an 18-month, randomized (1:1) clinical trial, sample size savings up to 30% were possible when enrollment was enriched for the Progressive trajectory versus no enrichment.

CONCLUSIONS

It is possible to predict ambulatory abilities from clinical data that are associated with meaningful outcomes in people with early PD. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

The Impact of Polypharmacy on Management of Lower Urinary Tract Symptoms in Parkinson's Disease

Lower urinary tract (LUT) symptoms are a common presentation of autonomic dysfunction in Parkinson's disease (PD). Symptoms significantly impact quality of life and are associated with worsening of motor symptoms and increased risk for falls. Different medical co-morbidities can often contribute to LUT symptoms, and a thorough evaluation therefore becomes essential. The effects of medications used for Parkinson's disease and other co-existing medical co-morbidities on LUT symptoms is often underestimated. Treatment options include behavioural therapy, oral agents such as antimuscarinic and beta-3 receptor agonist agents, botulinum toxin and neuromodulation. The first-line oral agents cause adverse effects that may exacerbate pre-existing Parkinson's disease-related symptoms. Furthermore, these oral agents can interact with other medications used in Parkinson's disease, and the challenges posed by interactions on pharmacological effects and metabolism are discussed. Knowledge about drug interactions can help in effective management of such patients and mitigate the risks for developing adverse effects.

Development of the Swedish anticholinergic burden scale (Swe-ABS)

BACKGROUND

Drugs with anticholinergic properties are associated with cognitive adverse effects, especially in patients vulnerable to central muscarinic antagonism. A variety of drugs show weak, moderate or strong anticholinergic effects. Therefore, the cumulative anticholinergic burden should be considered in patients with cognitive impairment. This study aimed to develop a Swedish Anticholinergic Burden Scale (Swe-ABS) to be used in health care and research.

METHODS

A systematic literature review was conducted in PubMed and Ovid Embase to identify previously published tools quantifying anticholinergic drug burden (i.e., exposure). Drugs and grading scores (0-3, no to high anticholinergic activity) were extracted from identified lists. Enteral and parenteral drugs authorized in Sweden were included. Drugs with conflicting scores in the existing lists were assessed by an expert group. Two drugs that were not previously assessed were also added to the evaluation process.

RESULTS

The systematic literature search identified the following nine anticholinergic burden scales: Anticholinergic Activity Scale, Anticholinergic Burden Classification, updated Anticholinergic Cognitive Burden scale, Anticholinergic Drug Scale, Anticholinergic Load Scale, Anticholinergic Risk Scale, updated Clinician-rated Anticholinergic Scale, German Anticholinergic Burden Scale and Korean Anticholinergic Burden Scale. A list of drugs with significant anticholinergic effects provided by The Swedish National Board of Health and Welfare was included in the process. The suggested Swe-ABS consists of 104 drugs scored as having weak, moderate or strong anticholinergic effects. Two hundred and fifty-six drugs were listed as having no anticholinergic effects based on evaluation in previous scales. In total, 62 drugs were assessed by the expert group.

CONCLUSIONS

Swe-ABS is a simplified method to quantify the anticholinergic burden and is easy to use in clinical practice. Publication of this scale might make clinicians more aware of drugs with anticholinergic properties and patients' total anticholinergic burden. Further research is needed to validate the Swe-ABS and evaluate anticholinergic exposure versus clinically significant outcomes.

Screening and Targeting Risk Factors for Prodromal Synucleinopathy: Taking Steps toward a Prescriptive Multi-modal Framework

As the prevalence of Parkinson's disease (PD) grows, so too does the population at-risk of developing PD, those in the so-called prodromal period. This period can span from those experiencing subtle motor deficits yet not meeting full diagnostic criteria or those with physiologic markers of disease alone. Several disease-modifying therapies have failed to show a neuroprotective effect. A common criticism is that neurodegeneration, even in the early motor stages, has advanced too far for neuro-restoration-based interventions to be effective. Therefore, identifying this early population is essential. Once identified, these patients could then potentially benefit from sweeping lifestyle modifications to alter their disease trajectory. Herein, we review the literature on risk factors for, and prodromal symptoms of, PD with an emphasis on ones which may be modifiable in the earliest possible stages. We propose a process for identifying this population and speculate on some strategies which may modulate disease trajectory. Ultimately, this proposal warrants prospective studies.

Impact of Anticholinergic Medications on Speech Perception Performance after Cochlear Implantation

OBJECTIVE

To identify and characterize the impact of anticholinergic medications, which have known adverse effects on cognition in older adults, on speech perception after cochlear implantation.

STUDY DESIGN

Retrospective cohort.

SETTING

Tertiary referral center.

SUBJECT POPULATION

Adult patients who underwent cochlear implantation between January 2010 and September 2020 with speech perception scores at 3, 6, and 12 months.

INTERVENTIONS

Anticholinergic burden of patients' prescribed medications.

MAIN OUTCOME MEASURES

AzBio speech perception scores after implantation.

RESULTS

One hundred twenty-six patients had documented AzBio in quiet speech perception score at all three postactivation time points. Patients were divided into three groups by anticholinergic burden (ACB) score, including ACB = 0 (90 patients), 1 (23 patients), and ≥2 (13 patients). There was no statistically significant difference between ACB groups in audiologic performance at candidacy testing ( p = 0.77) or at 3 months after implantation ( p = 0.13). Beginning at 6 months, a lower mean AzBio was seen in patients with higher ACB scores (68% ACB = 0; 62% ACB = 1; 48.1% ACB ≥ 2; p = 0.03). At 12 months, there were further differences between the groups (71.0% ACB = 0, 69.5% ACB = 1, 48.0% ACB ≥2, p < 0.01). Controlling for the effects of age using multivariate linear regression showed persistent effects of ACB score on learning-related AzBio improvements. Comparatively, the negative impact of a single ACB score point was equivalent to nearly 10 years of aging ( p = 0.03).

CONCLUSIONS

Increased ACB is associated with worse speech perception scores after cochlear implantation, an effect that persists even when accounting for patient age, suggesting that these medications may have cognitive and learning effects that reduce cochlear implant performance.

Leveraging the regulatory framework to facilitate drug development in Parkinson's disease

There is an exigent need for disease-modifying and symptomatic treatment approaches for Parkinson's disease. A better understanding of Parkinson's disease pathophysiology and new insights in genetics has opened exciting new venues for pharmacological treatment targets. There are, however, many challenges on the path from discovery to drug approval. These challenges revolve around appropriate endpoint selection, the lack of accurate biomarkers, challenges with diagnostic accuracy, and other challenges commonly encountered by drug developers. The regulatory health authorities, however, have provided tools to provide guidance for drug development and to assist with these challenges. The main goal of the Critical Path for Parkinson's Consortium, a nonprofit public-private partnership part of the Critical Path Institute, is to advance these so-called drug development tools for Parkinson's disease trials. The focus of this chapter will be on how the health regulators' tools were successfully leveraged to facilitate drug development in Parkinson's disease and other neurodegenerative diseases.

Pharmacological Treatment of Tremor in Parkinson's Disease Revisited

The pathophysiology of Parkinson's disease (PD) tremor remains incompletely understood and there is a lack of clinical trials specifically addressing its pharmacological treatment. Levodopa is the most efficacious drug for most patients and should be used as primary approach to control troublesome tremor. While the efficacy of oral dopamine agonists on PD tremor has been demonstrated in controlled trials, there is no evidence of greater antitremor efficacy compared to levodopa. The magnitude of the antitremor effect of anticholinergics is generally lower than that of levodopa. Due to their adverse effects, anticholinergics have a limited role in selected young and cognitively intact patients. Propranolol may improve resting and action tremor and may be considered as an adjunct in patients with insufficient tremor response to levodopa and this also applies to clozapine, despite its unfavorable adverse effect profile. Treating motor fluctuations with MAO-B and COMT inhibitors, dopamine agonists, amantadine, or on-demand treatments such as subcutaneous or sublingual apomorphine and inhaled levodopa as well as with continuous infusions of levodopa or apomorphine will improve off period tremor episodes. For patients with drug-refractory PD tremor despite levodopa optimization deep brain stimulation and focused ultrasound are first-line considerations. Surgery can also be highly effective for the treatment medication-refractory tremor in selected patients without motor fluctuations. The present review highlights the clinical essentials of parkinsonian tremor, critically examines available trial data on the effects of medication and surgical approaches and provides guidance for the choice of treatments to control PD tremor in clinical practice.

Polymeric nanoparticles for dopamine and levodopa replacement in Parkinson's disease

As the world's population ages, the incidence of Parkinson's disease (PD), the second most common neurological ailment, keeps increasing. It is estimated that 1% of the global population over the age of 60 has the disease. The continuous loss of dopaminergic neurons and the concomitant brain depletion of dopamine levels represent the hallmarks of PD. As a result, current PD therapies primarily target dopamine or its precursor (levodopa). Therapeutic approaches that aim to provide an exogenous source of levodopa or dopamine are hindered by their poor bioavailability and the blood-brain barrier. Nevertheless, the fabrication of many polymeric nanoparticles has been exploited to deliver several drugs inside the brain. In addition to a brief introduction of PD and its current therapeutic approaches, this review covers novel polymeric nanoparticulate drug delivery systems exploited lately for dopamine and levodopa replacement in PD.

Effects of trihexyphenidyl on prefrontal executive function and spontaneous neural activity in patients with tremor-dominant Parkinson's disease: An fNIRS study

INTRODUCTION

The use of the anti-parkinsonian drug trihexyphenidyl (THP) to treat patients with Parkinson's disease (PD), particularly those with tremor-dominant PD (tdPD), has been well documented. Despite growing concerns about THP causing cognitive decline in tdPD patients, the underlying neural correlates remain unclear. Therefore, we investigated the effects of THP on prefrontal executive function and spontaneous neural activity in patients with tdPD by utilizing functional near-infrared spectroscopy (fNIRS).

METHODS

We recruited 30 patients with tdPD, including 15 patients receiving THP and 15 patients not receiving THP. We performed comprehensive neuropsychological and clinical assessments to evaluate each patient's cognitive function, mental status, and clinical symptoms. We measured brain activation elicited from the verbal fluency task (VFT) and changes in amplitude of low-frequency fluctuations (ALFF) at rest to investigate executive function and spontaneous neural activity, respectively. In addition, we examined the relationship between altered activation during task and resting state and neuropsychological and clinical data.

RESULTS

Compared with tdPD patients not taking THP, tdPD patients taking THP showed no differences on neuropsychological tests. However, there was insufficient activity of the dorsolateral prefrontal cortex (DLPFC) during VFT and reduced ALFF values for the DLPFC, ventrolateral prefrontal cortex (VLPFC), and the orbitofrontal cortex (OFC) related to the frontoparietal network (FPN) at rest. Furthermore, ALFF values of the VLPFC were positively correlated with scores of multiple cognitive domain functions.

CONCLUSION

These findings suggest that THP treatment may lead to prefrontal dysfunction in tdPD patients, attenuating brain activation in executive function and cognition-related spontaneous neural activity.

Apolipoprotein A-I mimetic peptides (ApoAI MP) improve oxidative stress and inflammatory responses in Parkinson’s disease mice

Purpose: Parkinson’s disease (PD) is closely associated with oxidative stress and inflammatory situation. Apolipoprotein A-I mimetic peptides (ApoAI MP) have antioxidant and anti-inflammatory properties. We aimed to study the therapeutic effect of ApoAI MP on PD mice, and to explore the related mechanisms.

Methods: PD mice were induced by using 1-methyl-4-phenyl-1,2,3,6-tetrathydropyridine (MPTP). The model mice were treated with different concentrations of ApoAI MP. The open-field behavioral test assesses the total distance moved, the rest time, and the number of crossings and Rota-rod was used to evaluate motor coordination. Oxidative stress was identified by measuring the levels of superoxide dismutase (SOD), catalase (CAT), glutathionperoxidase (GSH-Px), malondialdehyde, ROS and H2O2. Inflammatory situation was analyzed by measuring the levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6). Meanwhile, the scavenging activities of ApoAI MP for ABTS, DPPH, hydroxyl radical and superoxide anion, and the effects of the peptide on neurotransmitters were evaluated.

Results: PD model establishment increased oxidative stress and inflammatory status by increasing the concentrations of ROS and H2O2 production, and the levels of TNF-α, IL-1β and IL-6 (p &lt; 0.05). ApoAI MP intervention improved PD symptoms by reducing the total moved distance and the number of passes (p &lt; 0.01), and the falling times from Rota-rod, and increasing rest time (p &lt; 0.05). ApoAI MP increased antioxidant properties by increasing the activities of SOD, CAT and GSH-Px, and reducing MDA concentration (p &lt; 0.05). ApoAI MP addition reduced oxidative stress by scavenging ABTS, DPPH, hydroxyl radicals and superoxide anion and reducing the concentrations of ROS and H2O2 production (p &lt; 0.05). ApoAI MP treatment increased anti-inflammatory capacities by reducing the concentrations of TNF-α, IL-1β and IL-6 (p &lt; 0.05). HPLC analysis showed that the peptide treatment improved neurotransmitters.

Conclusion: ApoAI MP can improve the behavioral performance of PD mice by improving antioxidant and anti-inflammatory capacities.

Anticholinergic Medication Burden in Parkinson's Disease Outpatients

BACKGROUND

Individuals with Parkinson's disease (PD) may be especially vulnerable to future cognitive decline from anticholinergic medications.

OBJECTIVE

To characterize anticholinergic medication burden, determine the co-occurrence of anticholinergic and cholinesterase inhibitors, and to assess the correlations among anticholinergic burden scales in PD outpatients.

METHODS

We studied 670 PD outpatients enrolled in a clinic registry between 2012 and 2020. Anticholinergic burden was measured with the Anticholinergic Cognitive Burden Scale (ACB), Anticholinergic Drug Scale (ADS), Anticholinergic Risk Scale (ARS), and Drug Burden Index-Anticholinergic component (DBI-Ach). Correlations between scales were assessed with weighted kappa coefficients.

RESULTS

Between 31.5 to 46.3% of PD patients were taking medications with anticholinergic properties. Among the scales applied, the ACB produced the highest prevalence of medications with anticholinergic properties (46.3%). Considering only medications with definite anticholinergic activity (scores of 2 or 3 on ACB, ADS, or ARS), the most common anticholinergic drug classes were antiparkinsonian (8.2%), antipsychotic (6.4%), and urological (3.3%) medications. Cholinesterase inhibitors and medications with anticholinergic properties were co-prescribed to 5.4% of the total cohort. The most highly correlated scales were ACB and ADS (κ= 0.71), ACB and ARS (κ= 0.67), and ADS and ARS (κ= 0.55).

CONCLUSION

A high proportion of PD patients (20%) were either taking antiparkinsonian, urological, or antipsychotic anticholinergic medications or were co-prescribed anticholinergic medications and cholinesterase inhibitors. By virtue of its detection of a high prevalence of anticholinergic medication usage and its high correlation with other scales, our data support use of the ACB scale to assess anticholinergic burden in PD patients.

Anticholinergic Burden, Polypharmacy, and Cognition in Parkinson's Disease Patients with Mild Cognitive Impairment: A Cross-Sectional Observational Study

INTRODUCTION

Anticholinergic burden may be an important risk factor for the cognitive impairment. Especially in polypharmacy, even drugs with low anticholinergic effects may contribute to a significant anticholinergic burden. The drugs with anticholinergic effects are used in treatment of motor and nonmotor symptoms of Parkinson's disease (PD). Therefore, it is important to screen for polypharmacy and anticholinergic burden in PD patients with mild cognitive impairment (MCI).

METHODS

This cross-sectional study was conducted with 58 patients with PD. PD-MCI was diagnosed according to MDS Level 2 Comprehensive Assessment. Cognitive performance (attention - working memory, executive functions, language, memory, and visuospatial functions) of patients was evaluated. The anticholinergic burden was scored by Anticholinergic Cognitive Burden (ACB) Scale, Anticholinergic Risk Scale (ARS), and Anticholinergic Drug Scale (ADS).

RESULTS

There was no significant difference in anticholinergic burden between PD-MCI and PD-normal cognition. A significant concordance was observed between ACB, ARS, and ADS scores (p < 0.001; Kendall's W = 0.653). While the variable predicting anticholinergic burden was the total number of drugs for ACB and ADS scales, it was the number of antiparkinson drugs for ARS scale.

CONCLUSION

Patients with PD are at high risk for polypharmacy and anticholinergic burden. Anticholinergic burden should be considered in the selection of drugs, especially for comorbidities in patients with PD. No significant correlation was found between the cognition and anticholinergic burden in patients with PD-MCI. Although the risk scores of antiparkinson and other drugs were different among the 3 scales, significant concordance was observed between scales.

Potential roles of gut microbiota and microbial metabolites in Parkinson's disease

Parkinson's disease (PD) is a complicated neurodegenerative disease attributed to multifactorial changes. However, its pathological mechanism remains undetermined. Accumulating evidence has revealed the emerging functions of gut microbiota and microbial metabolites, which can affect both the enteric nervous system and the central nervous system via the microbiota-gut-brain axis. Accordingly, intestinal dysbiosis might be closely associated with PD. This review explores alterations to gut microbiota, correlations with clinical manifestations of PD, and briefly probes the underlying mechanisms. Next, the highly controversial roles of microbial metabolites including short-chain fatty acids (SCFAs), H₂ and H₂S are discussed. Finally, the pros and cons of the current treatments for PD, including those targeting microbiota, are assessed. Advancements in research techniques, further studies on levels of specific strains and longitudinal prospective clinical trials are urgently needed for the identification of early diagnostic markers and the development of novel therapeutic approaches for PD.

An Update on Medical and Surgical Treatments of Parkinson's Disease

Parkinson’s disease (PD) is characterized by degeneration of dopaminergic neurons in the substantia nigra pars compacta and other neuronal populations. The worldwide prevalence of PD is over 7 million and has been increasing more rapidly than many other neurodegenerative disorders. PD symptoms can be broadly divided into motor (slowness, stiffness, tremor) and non-motor symptoms (such as depression, dementia, psychosis, orthostatic hypotension). Patients can also have prodromal symptoms of rapid eye movement sleep behavior disorder, hyposmia, and constipation. The diagnosis of PD is mainly clinical, but dopamine transporter single-photon emission computed tomography can improve the accuracy of the diagnosis. Dopamine based therapies are used for the treatment of motor symptoms. Non-motor symptoms are treated with other medications such as selective serotonin reuptake inhibitors (depression/anxiety), acetylcholinesterase inhibitors (dementia), and atypical antipsychotics (psychosis). Patients with motor fluctuations or uncontrolled tremor, benefit from deep brain stimulation. Levodopa-carbidopa intestinal gel is an alternative to deep brain stimulation for uncontrolled motor fluctuations. Rehabilitative therapies such as physical, occupational, and speech therapy are important during all stages of the disease. Management of PD is complex but there have been significant advancements in the treatment of motor and non-motor symptoms over the past few years. This review discusses the updates in the medical and surgical management of PD.