Cognitive impairment and dementia in Parkinson's disease: clinical features, diagnosis, and management

Emerging pharmacological approaches for Huntington's disease

Huntington's disease (HD) is a progressive neurodegenerative disorder characterized by cognitive, motor, and psychiatric symptoms. Despite significant advances in understanding the underlying molecular mechanisms of HD, there is currently no cure or disease-modifying treatment available. Emerging pharmacological approaches offer promising strategies to alleviate symptoms and slow down disease progression. This comprehensive review aims to provide a critical appraisal of the latest developments in pharmacological interventions for HD. The review begins by discussing the pathogenesis of HD, focusing on the role of mutant huntingtin protein, mitochondrial dysfunction, excitotoxicity, and neuro-inflammation. It then explores emerging therapeutic targets, including the modulation of protein homeostasis, mitochondrial function, neuro-inflammation, and neurotransmitter systems. Pharmacological agents targeting these pathways are discussed, including small molecules, gene-based therapies, and neuroprotective agents. In recent years, several clinical trials have been conducted to evaluate the safety and efficiency of novel compounds for HD. This review presents an update on the outcomes of these trials, highlighting promising results and challenges encountered. Additionally, it discusses the potential of repurposing existing drugs approved for other indications as a cost-effective approach for HD treatment. The review concludes by summarizing the current state of pharmacological approaches for HD and outlining future directions in drug development. The integration of multiple therapeutic strategies, personalized medicine approaches, and combination therapies are highlighted as potential avenues to maximize treatment effectiveness.

Hippocampus and olfactory impairment in Parkinson disease: a comparative exploratory combined volumetric/functional MRI study

INTRODUCTION

Patients with Parkinson's Disease (PD) commonly experience Olfactory Dysfunction (OD). Our exploratory study examined hippocampal volumetric and resting-state functional magnetic resonance imaging (rs-fMRI) variations in a Healthy Control (HC) group versus a cognitively normal PD group, further categorized into PD with No/Mild Hyposmia (PD-N/MH) and PD with Severe Hyposmia (PD-SH).

METHODS

We calculated participants' relative Total Hippocampal Volume (rTHV) and performed Spearman's partial correlations, controlled for age and gender, to examine the correlation between rTHV and olfactory performance assessed by the Odor Stick Identification Test for the Japanese (OSIT-J) score. Mann-Whitney U tests assessed rTHV differences across groups and subgroups, rejecting the null hypothesis for p < 0.05. Furthermore, a seed-based rs-fMRI analysis compared hippocampal connectivity differences using a one-way ANCOVA covariate model with controls for age and gender.

RESULTS

Spearman's partial correlations indicated a moderate positive correlation between rTHV and OSIT-J in the whole study population (ρ = 0.406; p = 0.007), PD group (ρ = 0.493; p = 0.008), and PD-N/MH subgroup (ρ = 0.617; p = 0.025). Mann-Whitney U tests demonstrated lower rTHV in PD-SH subgroup compared to both HC group (p = 0.013) and PD-N/MH subgroup (p = 0.029). Seed-to-voxel rsfMRI analysis revealed reduced hippocampal connectivity in PD-SH subjects compared to HC subjects with a single cluster of voxels.

CONCLUSIONS

Although the design of the study do not allow to make firm conclusions, it is reasonable to speculate that the progressive involvement of the hippocampus in PD patients is associated with the progression of OD.

Neuropsychological Assessment for Early Detection and Diagnosis of Dementia: Current Knowledge and New Insights

Dementia remains an underdiagnosed syndrome, and there is a need to improve the early detection of cognitive decline. This narrative review examines the role of neuropsychological assessment in the characterization of cognitive changes associated with dementia syndrome at different states. The first section describes the early indicators of cognitive decline and the major barriers to their identification. Further, the optimal cognitive screening conditions and the most widely accepted tests are described. The second section analyzes the main differences in cognitive performance between Alzheimer's disease and other subtypes of dementia. Finally, the current challenges of neuropsychological assessment in aging/dementia and future approaches are discussed. Essentially, we find that current research is beginning to uncover early cognitive changes that precede dementia, while continuing to improve and refine the differential diagnosis of neurodegenerative disorders that cause dementia. However, neuropsychology faces several barriers, including the cultural diversity of the populations, a limited implementation in public health systems, and the adaptation to technological advances. Nowadays, neuropsychological assessment plays a fundamental role in characterizing cognitive decline in the different stages of dementia, but more efforts are needed to develop harmonized procedures that facilitate its use in different clinical contexts and research protocols.

Cortical and subcortical functional connectivity and cognitive impairment in Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disease with cognitive as well as motor impairments. While much is known about the brain networks leading to motor impairments in PD, less is known about the brain networks contributing to cognitive impairments. Here, we leveraged resting-state functional magnetic resonance imaging (rs-fMRI) data from the Parkinson's Progression Marker Initiative (PPMI) to examine network dysfunction in PD patients with cognitive impairment. We focus on canonical cortical networks linked to cognition, including the salience network (SAL), frontoparietal network (FPN), and default mode network (DMN), as well as a subcortical basal ganglia network (BGN). We used the Montreal Cognitive Assessment (MoCA) as a continuous index of coarse cognitive function in PD. In 82 PD patients, we found that lower MoCA scores were linked with lower intra-network connectivity of the FPN. We also found that lower MoCA scores were linked with lower inter-network connectivity between the SAL and the BGN, the SAL and the DMN, as well as the FPN and the DMN. These data elucidate the relationship of cortical and subcortical functional connectivity with cognitive impairments in PD.

Compound impact of cognitive and physical decline: A qualitative interview study of people with Parkinson's and cognitive impairment, caregivers and professionals

BACKGROUND

Cognitive impairment is common in Parkinson's disease and is associated with poorer quality of life and increased caregiver distress, but little qualitative information is available on lived experiences of people with Parkinson's who also have cognitive impairment.

OBJECTIVES

The aim of this study was to explore the challenges of cognitive impairment in Parkinson's, triangulating the perspectives of people with Parkinson's, caregivers and healthcare professionals.

METHODS

Semistructured interviews were conducted with 11 people with Parkinson's and cognitive impairment, 10 family caregivers and 27 healthcare professionals, using purposive sampling in the United Kingdom (2019-2021). Cognitive impairment was identified by healthcare professionals and required subjective symptoms. Relevant cognitive diagnoses were recorded. Interviews were audio-recorded, transcribed and analysed using reflexive thematic analysis.

RESULTS

An overarching concept of the compound impact of cognitive and physical decline was developed, with six themes. Four themes describe the experience of living with cognitive impairment in Parkinson's: (1) Challenges in Daily Activities, (2) Psychological Impact and (3) Evolving Communication Difficulties together contributing to (4) Social Shift, encompassing a reduction in wider social activities but intensification of close relationships with increased dependence. A fifth theme (5) Living Well describes positive influences on these experiences, encompassing intrinsic motivation, self-management strategies and supportive relationships. Furthermore, underlying and shaping the whole experience was the sixth theme: (6) Preconceptions about Cognitive Impairment, describing fear and denial of symptoms and poor understanding of the nature of cognitive impairment in Parkinson's, with differences to other dementia pathologies.

CONCLUSIONS

Cognitive impairment superimposed on the existing challenges of Parkinson's has a multifaceted impact and makes living with the condition arduous. Increased understanding of the experiences of this group and employing the identified facilitators for living well may be able to improve patient and caregiver experiences.

PATIENT OR PUBLIC CONTRIBUTION

Two people with Parkinson's and cognitive impairment and three caregivers contributed to the study. Between them they contributed throughout the entirety of the project, giving input at conceptualisation as well as advice and review of interview questions, participant information leaflets, recruitment, interpretation of findings and summaries of the project.

Neurological gait assessment

Gait disorders are a common feature of neurological disease. The gait examination is an essential part of the neurological clinical assessment, providing valuable clues to a myriad of causes. Understanding how to examine gait is not only essential for neurological diagnosis but also for treatment and prognosis. Here, we review aspects of the clinical history and examination of neurological gait to help guide gait disorder assessment. We focus particularly on how to differentiate between common gait abnormalities and highlight the characteristic features of the more prevalent neurological gait patterns such as ataxia, waddling, steppage, spastic gait, Parkinson's disease and functional gait disorders. We also offer diagnostic clues for some unusual gait presentations, such as dystonic, stiff-person and choreiform gait, along with red flags that help differentiate atypical parkinsonism from Parkinson's disease.

Pathobiology of Cognitive Impairment in Parkinson Disease: Challenges and Outlooks

Cognitive impairment (CI) is a characteristic non-motor feature of Parkinson disease (PD) that poses a severe burden on the patients and caregivers, yet relatively little is known about its pathobiology. Cognitive deficits are evident throughout the course of PD, with around 25% of subtle cognitive decline and mild CI (MCI) at the time of diagnosis and up to 83% of patients developing dementia after 20 years. The heterogeneity of cognitive phenotypes suggests that a common neuropathological process, characterized by progressive degeneration of the dopaminergic striatonigral system and of many other neuronal systems, results not only in structural deficits but also extensive changes of functional neuronal network activities and neurotransmitter dysfunctions. Modern neuroimaging studies revealed multilocular cortical and subcortical atrophies and alterations in intrinsic neuronal connectivities. The decreased functional connectivity (FC) of the default mode network (DMN) in the bilateral prefrontal cortex is affected already before the development of clinical CI and in the absence of structural changes. Longitudinal cognitive decline is associated with frontostriatal and limbic affections, white matter microlesions and changes between multiple functional neuronal networks, including thalamo-insular, frontoparietal and attention networks, the cholinergic forebrain and the noradrenergic system. Superimposed Alzheimer-related (and other concomitant) pathologies due to interactions between α-synuclein, tau-protein and β-amyloid contribute to dementia pathogenesis in both PD and dementia with Lewy bodies (DLB). To further elucidate the interaction of the pathomechanisms responsible for CI in PD, well-designed longitudinal clinico-pathological studies are warranted that are supported by fluid and sophisticated imaging biomarkers as a basis for better early diagnosis and future disease-modifying therapies.

Salience network and cognitive impairment in Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disease with cognitive as well as motor impairments. While much is known about the brain networks leading to motor impairments in PD, less is known about the brain networks contributing to cognitive impairments. Here, we leveraged resting-state functional magnetic resonance imaging (rs-fMRI) data from the Parkinson's Progression Marker Initiative (PPMI) to examine network dysfunction in PD patients with cognitive impairment. We tested the hypothesis that cognitive impairments in PD involve altered connectivity of the salience network (SN), a key cortical network that detects and integrates responses to salient stimuli. We used the Montreal Cognitive Assessment (MoCA) as a continuous index of coarse cognitive function in PD. We report two major results. First, in 82 PD patients we found significant relationships between lower intra-network connectivity of the frontoparietal network (FPN; comprising the dorsolateral prefrontal and posterior parietal cortices bilaterally) with lower MoCA scores. Second, we found significant relationships between lower inter-network connectivity between the SN and the basal ganglia network (BGN) and the default mode network (DMN) with lower MoCA scores. These data support our hypothesis about the SN and provide new insights into the brain networks contributing to cognitive impairments in PD.

Prediction of Parkinson's disease pathogenic variants using hybrid Machine learning systems and radiomic features

PURPOSE

In Parkinson's disease (PD), 5-10% of cases are of genetic origin with mutations identified in several genes such as leucine-rich repeat kinase 2 (LRRK2) and glucocerebrosidase (GBA). We aim to predict these two gene mutations using hybrid machine learning systems (HMLS), via imaging and non-imaging data, with the long-term goal to predict conversion to active disease.

METHODS

We studied 264 and 129 patients with known LRRK2 and GBA mutations status from PPMI database. Each dataset includes 513 features such as clinical features (CFs), conventional imaging features (CIFs) and radiomic features (RFs) extracted from DAT-SPECT images. Features, normalized by Z-score, were univariately analyzed for statistical significance by the t-test and chi-square test, adjusted by Benjamini-Hochberg correction. Multiple HMLSs, including 11 features extraction (FEA) or 10 features selection algorithms (FSA) linked with 21 classifiers were utilized. We also employed Ensemble Voting (EV) to classify the genes.

RESULTS

For prediction of LRRK2 mutation status, a number of HMLSs resulted in accuracies of 0.98 ± 0.02 and 1.00 in 5-fold cross-validation (80% out of total data points) and external testing (remaining 20%), respectively. For predicting GBA mutation status, multiple HMLSs resulted in high accuracies of 0.90 ± 0.08 and 0.96 in 5-fold cross-validation and external testing, respectively. We additionally showed that SPECT-based RFs added value to the specific prediction of of GBA mutation status.

CONCLUSION

We demonstrated that combining medical information with SPECT-based imaging features, and optimal utilization of HMLS can produce excellent prediction of the mutations status in PD patients.

Delivering Optimal Care to People with Cognitive Impairment in Parkinson's Disease: A Qualitative Study of Patient, Caregiver, and Professional Perspectives

Background

Cognitive impairment is common in Parkinson's disease (PD) and associated with lower quality of life. Cognitive impairment in PD manifests differently to other dementia pathologies. Provision of optimal care requires knowledge about the support needs of this population.

Methods

Eleven people with PD and cognitive impairment (PwP), 10 family caregivers, and 27 healthcare professionals were purposively sampled from across the United Kingdom. Semistructured interviews were conducted in 2019-2021, audio-recorded, transcribed, and analysed using reflexive thematic analysis.

Results

Cognitive impairment in PD conveyed increased complexity for clinical management and healthcare interactions, the latter driven by multifactorial communication difficulties. Techniques that helped included slow, simple, and single messages, avoiding topic switching. Information and emotional support needs were often unmet, particularly for caregivers. Diagnostic pathways were inconsistent and awareness of cognitive impairment in PD was poor, both contributing to underdiagnosis. Many felt that PwP and cognitive impairment fell through service gaps, resulting from disjointed, nonspecific, and underresourced services. Personalised care was advocated through tailoring to individual needs of PwP and caregivers facilitated by flexibility, time and continuity within services, and supporting self-management.

Conclusions

This study highlights unmet need for people with this complex condition. Clinicians should adapt their approach and communication techniques for this population and provide tailored information and support to both PwP and caregivers. Services need to be more streamlined and collaborative, providing more time and flexibility. There is a need for wider awareness and deeper understanding of this condition and its differences from other types of dementia.

Parkinson's disease progression: Increasing expression of an invariant common core subnetwork

Notable success has been achieved in the study of neurodegenerative conditions using reduction techniques such as principal component analysis (PCA) and sparse inverse covariance estimation (SICE) in positron emission tomography (PET) data despite their widely differing approach. In a recent study of SICE applied to metabolic scans from Parkinson's disease (PD) patients, we showed that by using PCA to prespecify disease-related partition layers, we were able to optimize maps of functional metabolic connectivity within the relevant networks. Here, we show the potential of SICE, enhanced by disease-specific subnetwork partitions, to identify key regional hubs and their connections, and track their associations in PD patients with increasing disease duration. This approach enabled the identification of a core zone that included elements of the striatum, pons, cerebellar vermis, and parietal cortex and provided a deeper understanding of progressive changes in their connectivity. This subnetwork constituted a robust invariant disease feature that was unrelated to phenotype. Mean expression levels for this subnetwork increased steadily in a group of 70 PD patients spanning a range of symptom durations between 1 and 21 years. The findings were confirmed in a validation sample of 69 patients with up to 32 years of symptoms. The common core elements represent possible targets for disease modification, while their connections to external regions may be better suited for symptomatic treatment.

Limonene, a Monoterpene, Mitigates Rotenone-Induced Dopaminergic Neurodegeneration by Modulating Neuroinflammation, Hippo Signaling and Apoptosis in Rats

Rotenone (ROT) is a naturally derived pesticide and a well-known environmental neurotoxin associated with induction of Parkinson’s disease (PD). Limonene (LMN), a naturally occurring monoterpene, is found ubiquitously in citrus fruits and peels. There is enormous interest in finding novel therapeutic agents that can cure or halt the progressive degeneration in PD; therefore, the main aim of this study is to investigate the potential neuroprotective effects of LMN employing a rodent model of PD measuring parameters of oxidative stress, neuro-inflammation, and apoptosis to elucidate the underlying mechanisms. PD in experimental rats was induced by intraperitoneal injection of ROT (2.5 mg/kg) five days a week for a total of 28 days. The rats were treated with LMN (50 mg/kg, orally) along with intraperitoneal injection of ROT (2.5 mg/kg) for the same duration as in ROT-administered rats. ROT injections induced a significant loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) and DA striatal fibers following activation of glial cells (astrocytes and microglia). ROT treatment enhanced oxidative stress, altered NF-κB/MAPK signaling and motor dysfunction, and enhanced the levels/expressions of inflammatory mediators and proinflammatory cytokines in the brain. There was a concomitant mitochondrial dysfunction followed by the activation of the Hippo signaling and intrinsic pathway of apoptosis as well as altered mTOR signaling in the brain of ROT-injected rats. Oral treatment with LMN corrected the majority of the biochemical, pathological, and molecular parameters altered following ROT injections. Our study findings demonstrate the efficacy of LMN in providing protection against ROT-induced neurodegeneration.

Influence of cognitive reserve on cognitive and motor function in α-synucleinopathies: A systematic review protocol

Cognitive reserve has been used to justify neuropathologically unexplainable mismatches in Alzheimer's disease outcomes. Recent evidence has suggested this effect may be replicable across other conditions. However, it is still unclear whether cognitive reserve applies to α-synucleinopathies or to motor outcomes, or if medication confounds effects. This review protocol follows PRISMA-P guidelines and aims to investigate whether cognitive reserve can predict both cognitive and motor outcomes for α-synucleinopathy patients. MEDLINE (via PubMed), Scopus, psycINFO (via Ovid), CINAHL (via EBSCO), and Web of Science have been searched. Cross-sectional, cohort, case-control, and longitudinal studies investigating the association between cognitive reserve and cognitive and/or motor outcomes for Parkinson's disease, dementia with Lewy bodies, or multiple system atrophy will be included. Reviewers will independently perform screening, while also extracting data, assessing the risk of bias (using a version of the Quality in Prognostic Studies tool), and rating evidence quality (using GRADE). If possible, random-effects meta-analyses will be conducted for each unique outcome variable and α-synucleinopathy; otherwise, a narrative synthesis will be performed. Depending on the number of studies, exploratory analyses may involve meta-regression to assess potential confounding effects. Understanding the broader protective effect of cognitive reserve has significant implications for preventive interventions in the wider population.

[Features of visual, cognitive and neuroimaging changes in Parkinson's disease patients with freezing of gait]

OBJECTIVE

To determine visual and cognitive impairments in relation to MRI changes in patients with freezing of Gait (FOG) in Parkinson's disease (PD).

MATERIAL AND METHODS

We examined 78 patients with PD without dementia, who were divided into groups according to the presence (FOG«+» group) or absence (FOG«-» group) of «freezing» episodes.

RESULTS

A decrease in contrast sensitivity (CS) and retinal photosensitivity was determined in all subjects with PD, but in patients with FOG, the decrease in CS was more pronounced. There was a significant decrease in the volume of the cuneus, lingual gyrus, posterior cingulate gyrus, superior parietal lobe and middle frontal gyrus in the FOG«+» group. It was revealed that patients with FOG had cognitive impairments of both the frontal and posterior cortical subtypes, while in the FOG«-» group, only visuospatial deficit prevailed. A direct correlation was determined between the severity of FOG and part I of the UPDRS scale, between a decrease in CS and cortical areas related to the dorsal and ventral visual information processing systems. The presence of a negative relationship between the scores of the FOG-Q, Timed Up and Go test and the volume of cortical areas of the frontal lobe responsible for planning and programming of movements indicates their role in the development of FOG in PD.

CONCLUSION

Thus, visual impairments associated with PD, along with a heterogeneous profile of cognitive impairment, make a significant contribution to the development of FOG.

A Review on Response to Device-Aided Therapies Used in Monogenic Parkinsonism and GBA Variants Carriers: A Need for Guidelines and Comparative Studies

Parkinson's disease (PD) is in some cases predisposed-or-caused by genetic variants, contributing to the expression of different phenotypes. Regardless of etiology, as the disease progresses, motor fluctuations and/or levodopa-induced dyskinesias limit the benefit of pharmacotherapy. Device-aided therapies are good alternatives in advanced disease, including deep brain stimulation (DBS), levodopa-carbidopa intestinal gel, and continuous subcutaneous infusion of apomorphine. Candidate selection and timing are critical for the success of such therapies. Genetic screening in DBS cohorts has shown a higher proportion of mutation carriers than in general cohorts, suggesting that genetic factors may influence candidacy for advanced therapies. The response of monogenic PD to device therapies is not well established, and the contribution of genetic information to decision-making is still a matter of debate. The limited evidence regarding gene-dependent response to device-aided therapies is reviewed here. An accurate understanding of the adequacy and responses of different mutation carriers to device-aided therapies requires the development of specific studies with long-term monitoring.

Edge-based network analysis reveals frequency-specific network dynamics in aberrant anxiogenic processing in rats

Uncovering interactions between edges of brain networks can reveal the organizational principle of the networks and also their dysregulations underlying aberrant behaviours such as in neuropsychiatric diseases. In this study, we looked into the applicability of edge-based network analysis in uncovering possible network mechanisms of aberrant anxiogenic processing. Utilizing a rat model of prodromal Parkinson's disease we examined how a dorsomedial striatum-tied associative network (DSAN) may mediate context-based anxiogenic behaviour. Following dopamine depletion in the dorsomedial striatum, an exaggerated bottom-up signalling (posterior parietal-hippocampal-retrosplenial to anterior prefrontal-cingulate-amygdala regions) and gradient specific to the theta frequency in this network was observed. This change was accompanied by increased anxiety behaviour of the animals. By employing an edge-based approach in correlating informational flow (phase transfer entropy) with functional connectivity of all edges of this network, we further explore how the abnormal bottom-up signalling might be explained by alterations to the informational flow-connectivity motifs in the network. Our results demonstrate usage of edge-based network analysis in revealing concurrent informational processing and functional organization dynamics across multiple pathways in a brain network. This approach in unveiling network abnormalities and its impact on behavioural outcomes would be useful in probing the network basis of neuropsychiatric conditions.

Immersive Technology for Cognitive-Motor Training in Parkinson’s Disease

Background: Parkinson’s disease (PD) is a neurodegenerative disease in which the progressive loss of dopaminergic neurons (DA) leads to initially sporadic and eventually widespread damage of the nervous system resulting in significant musculoskeletal and cognitive deterioration. Loss of motor function alongside increasing cognitive impairment is part of the natural disease progression. Gait is often considered an automatic activity; however, walking is the result of a delicate balance of multiple systems which maintain the body’s center of mass over an ever-changing base of support. It is a complex motor behavior that requires components of attention and memory to prevent falls and injury. In addition, evidence points to the critical role of salient visual information to gait adaptability. There is a growing understanding that treatment for PD needs to address movement as it occurs naturally and walking needs to be practiced in more complex environments than traditional therapy has provided.

Traumatic brain injury and the development of parkinsonism: Understanding pathophysiology, animal models, and therapeutic targets

The clinical translation of therapeutic approaches to combat debilitating neurodegenerative conditions, such as Parkinson's disease (PD), remains as an urgent unmet challenge. The strong molecular association between the pathogenesis of traumatic brain injury (TBI) and the development of parkinsonism in humans has been well established. Therefore, a lot of ongoing research aims to investigate this pathology overlap in-depth, to exploit the common targets of TBI and PD for development of more effective and long-term treatment strategies. This review article intends to provide a detailed background on TBI pathophysiology and its established overlap with PD with an additional emphasis on the recent findings about their effect on perivascular clearance. Although, the traditional animal models of TBI and PD are still being considered, there is a huge focus on the development of combinatory hybrid animal models coupling concussion with the pre-established PD models for a better recapitulation of the human context of PD pathogenesis. Lastly, the therapeutic targets for TBI and PD, and the contemporary research involving exosomes, DNA vaccines, miRNA, gene therapy and gene editing for the development of potential candidates are discussed, along with the recent development of lesser invasive and promising central nervous system (CNS) drug delivery strategies.

The emerging postural instability phenotype in idiopathic Parkinson disease

Identification of individuals at high risk for rapid progression of motor and cognitive signs in Parkinson disease (PD) is clinically significant. Postural instability and gait dysfunction (PIGD) are associated with greater motor and cognitive deterioration. We examined the relationship between baseline clinical factors and the development of postural instability using 5-year longitudinal de-novo idiopathic data (n = 301) from the Parkinson’s Progressive Markers Initiative (PPMI). Logistic regression analysis revealed baseline features associated with future postural instability, and we designated this cohort the emerging postural instability (ePI) phenotype. We evaluated the resulting ePI phenotype rating scale validity in two held-out populations which showed a significantly higher risk of postural instability. Emerging PI phenotype was identified before onset of postural instability in 289 of 301 paired comparisons, with a median progression time of 972 days. Baseline cognitive performance was similar but declined more rapidly in ePI phenotype. We provide an ePI phenotype rating scale (ePIRS) for evaluation of individual risk at baseline for progression to postural instability.

Alzheimer's Disease-Associated SNP rs708727 in SLC41A1 May Increase Risk for Parkinson's Disease: Report from Enlarged Slovak Study

SLC41A1 (A1) SNPs rs11240569 and rs823156 are associated with altered risk for Parkinson's disease (PD), predominantly in Asian populations, and rs708727 has been linked to Alzheimer's disease (AD). In this study, we have examined a potential association of the three aforementioned SNPs and of rs9438393, rs56152218, and rs61822602 (all three lying in the A1 promoter region) with PD in the Slovak population. Out of the six tested SNPs, we have identified only rs708727 as being associated with an increased risk for PD onset in Slovaks. The minor allele (A) in rs708727 is associated with PD in dominant and completely over-dominant genetic models (OR_D = 1.36 (1.05-1.77), p = 0.02, and OR_COD = 1.34 (1.04-1.72), p = 0.02). Furthermore, the genotypic triplet GG_(rs708727) + AG_(rs823156) + CC_(rs61822602) might be clinically relevant despite showing a medium (h ≥ 0.5) size difference (h = 0.522) between the PD and the control populations. RandomForest modeling has identified the power of the tested SNPs for discriminating between PD-patients and the controls to be essentially zero. The identified association of rs708727 with PD in the Slovak population leads us to hypothesize that this A1 polymorphism, which is involved in the epigenetic regulation of the expression of the AD-linked gene PM20D1, is also involved in the pathoetiology of PD (or universally in neurodegeneration) through the same or similar mechanism as in AD.

Morphological classification and changes in dementia (Review)

The progressive functional decline that involves both cognitive and neuropsychiatric symptoms characteristic to dementia is one of the leading research topics. The risk for dementia is an intertwined mix between aging, genetic risk factors, and environmental influences. APOEε4, which is one of the apolipoprotein E (APOE) alleles, is the major genetic risk factor for late-onset of the most common form of dementia, Alzheimer's. Advances in machine learning have led to the development of artificial intelligence (AI) algorithms to help diagnose dementia by magnetic resonance imaging (MRI) in order to detect it in the preclinical stage. The basis of the determinations starts from the morphometry of cerebral atrophies. The present review focused on MRI techniques which are a leading tool in identifying cortical atrophy, white matter dysfunctionalities, cerebral vessel quality (as a factor for cognitive impairment) and metabolic asymmetries. In addition, a brief overview of Alzheimer's disease was presented and recent neuroimaging in the field of dementia with an emphasis on structural MR imaging and more powerful methods such as diffusion tensor imaging, quantitative susceptibility mapping, and magnetic transfer imaging were explored in order to propose a simple systematic approach for the diagnosis and treatment of dementia.

Exploration of Protein Aggregations in Parkinson's Disease Through Computational Approaches and Big Data Analytics

Protein aggregation has been implicated in numerous neurodegenerative disorders whose etiologies are poorly understood, and for which there are no effective treatments. Here we show that the computational approaches may help us to better understand the basics of Parkinson's disease (PD). The high-resolution structural, dynamical, and mechanistic insights delivered by computational studies of protein aggregation have a unique potential to enable the rational manipulation of oligomer formation. Additionally, big data and machine learning methods may provide valuable insights to better understand the nature of proteins involved in PD and their aggregative behavior for the betterment of PD treatment.

MNCD: A New Tool for Classifying Parkinson’s Disease in Daily Clinical Practice

Background and objective: Parkinson’s disease (PD) is a clinically heterogeneous disorder in which the symptoms and prognosis can be very different among patients. We propose a new simple classification to identify key symptoms and staging in PD. Patients and Methods: Sixteen movement disorders specialists from Spain participated in this project. The classification was consensually approved after a discussion and review process from June to October 2021. The TNM classification and the National Institutes of Health Stroke Scale (NIHSS) were considered as models in the design. Results: The classification was named MNCD and included 4 major axes: (1) motor symptoms; (2) non-motor symptoms; (3) cognition; (4) dependency for activities of daily living (ADL). Motor axis included 4 sub-axes: (1) motor fluctuations; (2) dyskinesia; (3) axial symptoms; (4) tremor. Four other sub-axes were included in the non-motor axis: (1) neuropsychiatric symptoms; (2) autonomic dysfunction; (3) sleep disturbances and fatigue; (4) pain and sensory disorders. According to the MNCD, 5 stages were considered, from stage 1 (no disabling motor or non-motor symptoms with normal cognition and independency for ADL) to 5 (dementia and dependency for basic ADL). Conclusions: A new simple classification of PD is proposed. The MNCD classification includes 4 major axes and 5 stages to identify key symptoms and monitor the evolution of the disease in patients with PD. It is necessary to apply this proof of concept in a properly designed study.

Mind–Body Exercises for Non-motor Symptoms of Patients With Parkinson’s Disease: A Systematic Review and Meta-Analysis

Objective: This study aimed to systematically evaluate the effects of mind–body exercise on global cognitive function, depression, sleep disorders, fatigue level, and quality of life (QOL) in a Parkinson’s disease (PD) population.

Methods: Total six English and Chinese databases were searched for articles published up to May 2021. Randomized controlled trials (RCTs) evaluating mind–body excises on non-motor symptoms of PD were included. The Cochrane risk of bias tool was used to assess the methodological quality, and we defined high-quality studies as having a low risk of bias in four or more domains. Global cognitive function was considered the primary outcome and was assessed using the Montreal Cognitive Assessment (MoCA). The secondary outcomes included QOL, fatigue, depression, and sleep quality, which were measured using the Parkinson’s Disease Questionnaire (PDQ-39), 16-item Parkinson’s Disease Fatigue Scale (PFS-16), Beck Depression Inventory (BDI), and revised Parkinson’s Disease Sleep Scale (PDSS-2), respectively. Subgroup analyses were conducted for global cognitive function and QOL to assess the optimal treatment measure across the various mind–body exercises.

Results: Fourteen RCTs with 404 patients were finally included in the meta-analysis. Eight (57.14%) studies were of high quality. The pooled results showed that mind–body exercises generally had a significant advantage over the control intervention in improving global cognitive function (MD = 1.68; P = 0.0008). The dose subgroup analysis revealed that the low dose (60–120 min per week) and moderate dose (120–200 min per week) significantly increased MoCA scores compared with the control group (MD = 2.11, P = 0.01; MD = 1.27, P = 0.02, respectively). The duration subgroup analysis indicated a significant difference in the effect of the duration (6–10 and >15 weeks) on increasing MoCA scores compared with the control group (MD = 3.74, P < 0.00001; MD = 1.45, P = 0.01, respectively).

Conclusion: Mind–body exercise may improve global cognitive function, sleep quality, and QOL in the PD population. In addition, low to moderate doses and appropriate durations significantly improved global cognitive function.

Clinical Trial Registration: [www.ClinicalTrials.gov], identifier [CRD42021275522].

Baicalein protects against MPP+/MPTP-induced neurotoxicity by ameliorating oxidative stress in SH-SY5Y cells and mouse model of Parkinson's disease

Baicalein, a major bioactive flavone constituent isolated from Scutellaria baicalensis Georgi, has neuroprotective properties in several neurological disorders. Many studies suggest that oxidative stress plays a central role in the pathogenesis of Parkinson's disease (PD). Baicalein has also been shown to have antioxidant effects. Therefore, the current study was designed to investigate whether baicalein could protect against MPP⁺/MPTP-induced neurotoxicity via suppressing oxidative stress in vitro and in vivo. In vitro, our results showed that baicalein increased cell viability in MPP⁺-treated SH-SY5Y cells. Treatment with baicalein could reversed the increased MDA and ROS levels, and the decreased GSH levels in MPP⁺-treated SH-SY5Y cells. In MPTP-treated mice, baicalein ameliorated MPTP-induced motor impairment and suppressed the MPTP-induced accumulation of iron and lipid peroxides. Besides, baicalein improved the neurotoxicity induced by MPTP as seen by a significant raise of tyrosine hydroxylase (TH) and simultaneous decrease of monoamine-oxidase-B (MAO-B). The inhibitory effect of baicalein on oxidative stress probably was partially governed by inhibition of ERK activation. In conclusion, our results suggest that baicalein could prevent MPP+/MPTP-induced neurotoxicity via suppressing oxidative stress.

(Dys)Prosody in Parkinson's Disease: Effects of Medication and Disease Duration on Intonation and Prosodic Phrasing

The phonology of prosody has received little attention in studies of motor speech disorders. The present study investigates the phonology of intonation (nuclear contours) and speech chunking (prosodic phrasing) in Parkinson’s disease (PD) as a function of medication intake and duration of the disease. Following methods of the prosodic and intonational phonology frameworks, we examined the ability of 30 PD patients to use intonation categories and prosodic phrasing structures in ways similar to 20 healthy controls to convey similar meanings. Speech data from PD patients were collected before and after a dopaminomimetic drug intake and were phonologically analyzed in relation to nuclear contours and intonational phrasing. Besides medication, disease duration and the presence of motor fluctuations were also factors included in the analyses. Overall, PD patients showed a decreased ability to use nuclear contours and prosodic phrasing. Medication improved intonation regardless of disease duration but did not help with dysprosodic phrasing. In turn, disease duration and motor fluctuations affected phrasing patterns but had no impact on intonation. Our study demonstrated that the phonology of prosody is impaired in PD, and prosodic categories and structures may be differently affected, with implications for the understanding of PD neurophysiology and therapy.

Brain Atrophy Mediates the Relationship between Misfolded Proteins Deposition and Cognitive Impairment in Parkinson's Disease

Parkinson’s disease is associated with cognitive decline, misfolded protein deposition and brain atrophy. We herein hypothesized that structural abnormalities may be mediators between plasma misfolded proteins and cognitive functions. Neuropsychological assessments including five domains (attention, executive, speech and language, memory and visuospatial functions), ultra-sensitive immunomagnetic reduction-based immunoassay (IMR) measured misfolded protein levels (phosphorylated-Tau, Amyloidβ-42 and 40, α-synuclein and neurofilament light chain) and auto-segmented brain volumetry using FreeSurfur were performed for 54 Parkinson’s disease (PD) patients and 37 normal participants. Our results revealed that PD patients have higher plasma misfolded protein levels. Phosphorylated-Tau (p-Tau) and Amyloidβ-42 (Aβ-42) were correlated with atrophy of bilateral cerebellum, right caudate nucleus, and right accumbens area (RAA). In mediation analysis, RAA atrophy completely mediated the relationship between p-Tau and digit symbol coding (DSC). RAA and bilateral cerebellar cortex atrophy partially mediated the Aβ-42 and executive function (DSC and abstract thinking) relationship. Our study concluded that, in PD, p-Tau deposition adversely impacts DSC by causing RAA atrophy. Aβ-42 deposition adversely impacts executive functions by causing RAA and bilateral cerebellum atrophy.

Exploring Nonmotor Neuropsychiatric Manifestations of Parkinson Disease in a Comprehensive Care Setting

Parkinson disease (PD) is a debilitating neurological condition that includes both motor symptoms and nonmotor symptoms (NMS). Psychiatric complaints comprise NMS and are collectively referred to as neuropsychiatric manifestations. Common findings include atypical depressive symptoms, anxiety, psychosis, impulse control disorder, deterioration of cognition, and sleep disturbances. Quality of life (QoL) of patients suffering from NMS is greatly impacted and many times can be more debilitating than motor symptoms of PD. We expand on knowledge gained from treatment models within a comprehensive care model that incorporates multidisciplinary specialists working alongside psychiatrists to treat PD. Insight into background, clinical presentations, and treatment options for patients suffering from neuropsychiatric manifestations of PD are discussed. Identifying symptoms early can help improve QoL, provide early symptom relief, and can assist tailoring treatment plans that limit neuropsychiatric manifestations.

Emulated Clinical Trials from Longitudinal Real-World Data Efficiently Identify Candidates for Neurological Disease Modification: Examples from Parkinson's Disease

Real-world healthcare data hold the potential to identify therapeutic solutions for progressive diseases by efficiently pinpointing safe and efficacious repurposing drug candidates. This approach circumvents key early clinical development challenges, particularly relevant for neurological diseases, concordant with the vision of the 21st Century Cures Act. However, to-date, these data have been utilized mainly for confirmatory purposes rather than as drug discovery engines. Here, we demonstrate the usefulness of real-world data in identifying drug repurposing candidates for disease-modifying effects, specifically candidate marketed drugs that exhibit beneficial effects on Parkinson's disease (PD) progression. We performed an observational study in cohorts of ascertained PD patients extracted from two large medical databases, Explorys SuperMart (N = 88,867) and IBM MarketScan Research Databases (N = 106,395); and applied two conceptually different, well-established causal inference methods to estimate the effect of hundreds of drugs on delaying dementia onset as a proxy for slowing PD progression. Using this approach, we identified two drugs that manifested significant beneficial effects on PD progression in both datasets: rasagiline, narrowly indicated for PD motor symptoms; and zolpidem, a psycholeptic. Each confers its effects through distinct mechanisms, which we explored via a comparison of estimated effects within the drug classification ontology. We conclude that analysis of observational healthcare data, emulating otherwise costly, large, and lengthy clinical trials, can highlight promising repurposing candidates, to be validated in prospective registration trials, beneficial against common, late-onset progressive diseases for which disease-modifying therapeutic solutions are scarce.

Medication Management Performance in Parkinson’s Disease: Examination of Process Errors

Objective

Individuals with Parkinson’s disease (PD) are at risk for increased medication mismanagement, which can lead to worse clinical outcomes. However, the nature of the errors (i.e., undertaking or overtaking medications) contributing to mismanagement and their relationship to cognition in PD is unknown. Therefore, this study sought to examine errors committed on the Medication Management Ability Assessment (MMAA) between PD participants with normal cognition (PD-NC) or mild cognitive impairment (PD-MCI) relative to healthy adults (HA).

Method

HA (n = 74), PD-NC (n = 102), and PD-MCI (n = 45) participants were administered the MMAA to assess undertaking, overtaking, and overall errors as well as overall performance (total score). Additionally, participants were administered a comprehensive neuropsychological battery from which cognitive composites of Attention, Learning, Memory, Language, Visuospatial, and Executive Functioning were derived.

Results

Separate negative binomial regression analyses indicated the PD-MCI group performed significantly worse overall on the MMAA (total score) and committed more undertaking and overall errors relative to HA and PD-NC. In the PD-MCI group, poorer MMAA performance was associated with worse delayed memory performance, whereas cognitive performance was not related to MMAA in HA or PC-NC.

Conclusion

Compared to PD and healthy adults with normal cognition, PD-MCI patients exhibited greater difficulty with medication management, particularly with undertaking medications. Poorer medication management in PD-MCI was associated with worse delayed recall. Thus, PD-MCI patients experiencing memory problems may require additional assistance with their medications. Findings have clinical relevance suggesting that objective measures of medication errors may assist clinicians in identifying PD patients needing adherence strategies.

Palliative Care in Movement Disorders: an Evolving Field

PURPOSE OF REVIEW

This review summarizes the current state of evidence for palliative care (PC) in movement disorders, describes the application of PC to clinical practice, and suggests future research directions.

RECENT FINDINGS

PC needs are common in persons living with movement disorders and their families from the time of diagnosis through end-of-life and contribute to quality of life. Early advance care planning is preferred by patients, impacts outcomes and is promoted by PC frameworks. Systematic assessment of non-motor symptoms, psychosocial needs and spiritual/existential distress may address gaps in current models of care. Several complementary and emerging models of PC may be utilized to meet the needs of this population. A PC approach may identify and improve important patient and caregiver-centered outcomes. As a relatively new application of PC, there is a need for research to adapt, develop and implement approaches to meet the unique needs of this population.

Is Methylphenidate Beneficial and Safe in Pharmacological Cognitive Enhancement?

Nootropics are drugs used to either treat or benefit cognition deficits. Among this class, methylphenidate is a popular agent, which acts through indirect dopaminergic and noradrenergic agonism and, therefore, is proposed to enhance performance in catecholamine-dependent cognitive domains such as attention, memory and prefrontal cortex-dependent executive functions. However, investigation into the efficacy of methylphenidate as a cognitive enhancer has yielded variable results across all domains, leading to debate within the scientific community surrounding its off-label use in healthy individuals seeking scholaristic benefit or increased productivity. Through analysis of experimental data and methodological evaluation, it is apparent that there are dose-, task- and domain-dependent considerations surrounding the use of methylphenidate in healthy individuals, whereby tailored dose administration is likely to provide benefit on an individual basis dependent on the domain of cognition in which benefit is required. Additionally, it is apparent that there are subjective effects of methylphenidate, which may increase user productivity irrespective of cognitive benefit. Whilst there is not extensive study in healthy older adults, it is plausible that there are dose-dependent benefits to methylphenidate in older adults in selective cognitive domains that might improve quality of life and reduce fall risk. Methylphenidate appears to produce dose-dependent benefits to individuals with attention-deficit/hyperactivity disorder, but the evidence for benefit in Parkinson's disease and schizophrenia is inconclusive. As with any off-label use of pharmacological agents, and especially regarding drugs with neuromodulatory effects, there are inherent safety concerns; epidemiological and experimental evidence suggests there are sympathomimetic, cardiovascular and addictive considerations, which might further restrict their use within certain demographics.

A feasibility trial of an internet-delivered psychological intervention to manage mental health and functional outcomes in neurological disorders

OBJECTIVE

Mental health and cognitive difficulties are highly prevalent across neurological disorders and significantly contribute to poorer patient outcomes. Unfortunately, access to effective psychological services for these comorbidities are limited. To determine whether a novel transdiagnostic internet-delivered psychological intervention, the Wellbeing Neuro Course, was feasible, acceptable and efficacious a single-group feasibility open trial was employed.

METHODS

The Wellbeing Neuro Course, targets mental health and cognitive difficulties, across a variety of neurological disorders. It is comprised of six online lessons, based on Cognitive Behavioural Therapy and Compensatory Cognitive Rehabilitation, delivered over 10 weeks and provided with weekly support from a mental health professional via email and telephone. 105 adults with diagnoses of either epilepsy, multiple sclerosis, Parkinson's disease and/or acquired brain injury, underwent the intervention.

RESULTS

The intervention was found to be highly acceptable with high intervention completion and levels of satisfaction (>95%). There was evidence of clinically significant improvements in primary outcomes (within-group Cohen's d; average reductions) of depression (d = 0.93; avg. reduction ≥36%), anxiety (ds = 0.66, avg. reduction ≥36%), and disability (ds ≥ 0.49; avg. reduction ≥23%) at post-intervention, maintained at 3-month follow-up. For secondary outcomes there were significant improvements in fatigue severity and perceived cognitive difficulties of attention, planning and prospective memory. Findings were achieved with minimal clinician time, highlighting its public health potential.

CONCLUSION

This open trial provides preliminary evidence the Wellbeing Neuro Course is acceptable and reduces symptoms of depression, anxiety and disability in neurological disorders. Future controlled trials of the intervention are now needed.

TRIAL REGISTRATION

ACTRN12617000581369.

Reduced Gray Matter Volume and Risk of Falls in Parkinson's Disease with Dementia Patients: A Voxel-Based Morphometry Study

Purpose: Risk of falls is a common sequela affecting patients with Parkinson’s disease (PD). Although motor impairment and dementia are correlated with falls, associations of brain structure and cognition deficits with falls remain unclear. Material and Methods: Thirty-five PD patients with dementia (PDD), and 37 age- and sex-matched healthy subjects were recruited for this study. All participants received structural magnetic resonance imaging (MRI) scans, and disease severity and cognitive evaluations. Additionally, patient fall history was recorded. Regional structural differences between PDD with and without fall groups were performed using voxel-based morphometry processing. Stepwise logistic regression analysis was used to predict the fall risk in PDD patients. Results: The results revealed that 48% of PDD patients experienced falls. Significantly lower gray matter volume (GMV) in the left calcarine and right inferior frontal gyrus in PDD patients with fall compared to PDD patients without fall were noted. The PDD patients with fall exhibited worse UPDRS-II scores compared to PDD patients without fall and were negatively correlated with lower GMV in the left calcarine (p/r = 0.004/−0.492). Furthermore, lower GMV in the left calcarine and right inferior frontal gyrus correlated with poor attention and executive functional test scores. Multiple logistic regression analysis showed that the left calcarine was the only variable (p = 0.004, 95% CI = 0.00–0.00) negatively associated with the fall event. Conclusions: PDD patients exhibiting impaired motor function, lower GMV in the left calcarine and right inferior frontal gyrus, and notable cognitive deficits may have increased risk of falls.

Targeting the endocannabinoid system: a predictive, preventive, and personalized medicine-directed approach to the management of brain pathologies

Cannabis-inspired medical products are garnering increasing attention from the scientific community, general public, and health policy makers. A plethora of scientific literature demonstrates intricate engagement of the endocannabinoid system with human immunology, psychology, developmental processes, neuronal plasticity, signal transduction, and metabolic regulation. Despite the therapeutic potential, the adverse psychoactive effects and historical stigma, cannabinoids have limited widespread clinical application. Therefore, it is plausible to weigh carefully the beneficial effects of cannabinoids against the potential adverse impacts for every individual. This is where the concept of "personalized medicine" as a promising approach for disease prediction and prevention may take into the account. The goal of this review is to provide an outline of the endocannabinoid system, including endocannabinoid metabolizing pathways, and will progress to a more in-depth discussion of the therapeutic interventions by endocannabinoids in various neurological disorders.

RADPAC-PD: A tool to support healthcare professionals in timely identifying palliative care needs of people with Parkinson's disease

Background

Parkinson’s disease (PD) is a progressive degenerative disease without curative treatment perspectives. Even when palliative care for people with PD seems to be beneficial, the need for palliative care is often not timely recognized.

Aim

Our aim was to develop a tool that can help healthcare professionals in timely identifying palliative care needs in people with PD.

Design

We used a mixed-methods design, including individual and focus group interviews and a three-round modified Delphi study with healthcare professionals from a multidisciplinary field.

Results

Data from the interviews suggested two distinct moments in the progressive PD trajectory: 1) an ultimate moment to initiate Advance Care Planning (ACP); and 2) the actual start of the palliative phase. During the Delphi process, six indicators for ACP were identified, such as presence of frequent falls and first unplanned hospital admission. The start of the palliative phase involved four indicators: 1) personal goals have started to focus on maximization of comfort; 2) care needs have changed; 3) PD drug treatment has become less effective or an increasingly complex regime of drug treatments is needed; and 4) specific PD-symptoms or complications have appeared, such as significant weight loss, recurrent infections, or progressive dysphagia. Indicators for both moments are included in the RADboud indicators for PAlliative Care Needs in Parkinson’s Disease (RADPAC-PD) tool.

Conclusion

The RADPAC-PD may support healthcare professionals in timely initiating palliative care for persons with PD. Identification of one or more indicators can mark the need for ACP or the palliative phase. We expect that applying the RADPAC-PD, for example on an annual basis throughout the PD trajectory, can facilitate identification of the palliative phase in PD patients in daily practice. However, further prospective research is needed on the implementation of the RADPAC-PD.

Atomoxetine Does Not Improve Complex Attention in Idiopathic Parkinson's Disease Patients with Cognitive Deficits: A Meta-Analysis

Objectives

To evaluate the effects of atomoxetine on complex attention and other neurocognitive domains in idiopathic Parkinson's disease (PD).

Methods

Interventional trials reporting changes in complex attention and other neurocognitive functions (Diagnostic and Statistical Manual of Mental Disorders-5) following administration of atomoxetine for at least 8 weeks in adults with idiopathic PD were included. Effect sizes (Cohen's d), the standardized mean difference in the scores of each cognitive domain, were compared using a random-effects model (MetaXL version 5.3).

Results

Three studies were included in the final analysis. For a change in complex attention in PD with mild cognitive impairment (MCI), the estimated effect size was small and nonsignificant (0.16 (95% CI: −0.09, 0.42), n = 42). For changes in executive function, perceptual-motor function, language, social cognition, and learning and memory, the estimated effect sizes were small and medium, but nonsignificant. A deteriorative trend in executive function was observed after atomoxetine treatment in PD with MCI. For a change in global cognitive function in PD without MCI, the estimated effect size was large and significant.

Conclusion

In idiopathic PD with MCI, atomoxetine does not improve complex attention. Also, a deteriorative trend in the executive function was noted.

Cognitive workload during verbal abstract reasoning in Parkinson's disease: a pilot study

BACKGROUND

Pupillary response reflects cognitive workload during processing speed, working memory, and arithmetic tasks in Parkinson's disease (PD). Abstract reasoning, a higher-order cognitive function that relates different objects, events, or thoughts in a similar manner, may also be compromised in PD. The aim of this study was to compare pupillary response as a measure of cognitive workload while completing a verbal abstract reasoning test between patients with PD and age-matched controls.

METHODS

Nineteen non-demented individuals with PD (66.6 ± 8.9 years) and 10 healthy controls (65.3 ± 7.3 years) were recruited. A remote eye tracker recorded the pupillary response at 60 Hz, while the participants were performing the Similarities test of Wechsler Adult Intelligence Scale-IV. Outcome measures included pupillary response, evaluated by the Index of Cognitive Activity (ICA), and behavioral responses of the Similarities test.

RESULTS

The PD group (scaled scores = 8.9 ± 2.2) did not show impairment in behavioral performance on Similarities test compared with healthy controls (scaled scores = 8.8 ± 2.3; p = .91). However, the PD group (ICA = .32 ± .09) demonstrated significantly greater cognitive workload during the Similarities test compared to controls (ICA = .24 ± .08; p = .03).

CONCLUSIONS

Non-demented individuals with PD exerted greater cognitive workload to complete a verbal abstract reasoning task despite similar behavioral performance compared to healthy controls. Clinical utilities of pupillary response to detect and monitor early impairment in higher-order executive function will be the subject of further study in the PD population.

Cognitive anosognosia is associated with frontal dysfunction and lower depression in Parkinson's disease

BACKGROUND AND PURPOSE

Anosognosia refers to a deficit of self-awareness or impaired insight for cognitive and behavioral problems. Cognitive anosognosia was explored in de novo patients with Parkinson's disease (PD) and its relationship to cognitive function and neuropsychiatric symptoms was investigated.

METHODS

The cross-sectional study enrolled 340 drug-naïve patients with PD. According to the presence of mild cognitive impairment (MCI) and subjective cognitive complaint, patients were classified as patients with cognitive anosognosia (PD-CA, n = 74), with normal cognitive recognition (PD-NR, n = 184) or with cognitive underestimation (PD-CU, n = 82). After controlling for covariates, cognitive performance and neuropsychiatric symptoms were compared between the PD groups.

RESULTS

Cognitive anosognosia was found in 21.8% of patients with de novo PD. The PD-CA group showed poorer performance in all cognitive domains except for attention. Amongst PD patients with MCI, those with cognitive anosognosia showed lower composite z-scores in the Stroop color reading test than those without. The Beck Depression Inventory score in the PD-NR group was lower than that in the PD-CU group and higher than that in the PD-CA group. The Cognitive Complaints Interview score mediated the association between cognitive anosognosia and Beck Depression Inventory score.

CONCLUSIONS

Cognitive anosognosia in PD was associated with greater frontal dysfunction and lower depression. Since cognitive anosognosia has a harmful impact on PD patients and their caregivers due to overestimation of their abilities in everyday life, early identification of cognitive anosognosia in PD is important in management and prognosis.

Predictors and Level of Knowledge Regarding Parkinson's Disease among Patients: A Cross-sectional Study from Thailand

Background:

Parkinson's disease (PD) is a neurodegenerative disorder that results in gradual decline of motor, autonomic, and neuropsychiatric functions of the patient. Knowledge and factors responsible for Parkinson's disease (PD) are important among patients that could positively affect their attitude and perceptions. This study was conducted to determine the factors influencing and level of the knowledge regarding Parkinson's disease in Thailand.

Methods:

This cross-sectional study was conducted on 125 patients admitted in King Chulalongkorn Memorial Hospital Bangkok, Thailand. Sociodemographic variables and clinical characteristics were collected as predictors of knowledge, treatment, and self-care for PD. A validated, piloted, pretested tool was used for data collection. Multiple linear regressions were used to find the most influencing predictor of knowledge about PD. The study was approved by the Ethical Board of Chulalongkorn University, Thailand.

Results:

The level of education was found to be the most significant (P = 0.005) predictor of PD knowledge. PD patients with high education had significantly higher knowledge scores than those with low education in all aspects of disease (P = 0.041), treatment (P = 0.014), and self-care (P = 0.011). PD knowledge was poor in variables such as levodopa (62%), nonmotor symptoms (54%), and stem cell transplantation (40%), respectively.

Conclusion:

The study results conclude that educational level is the most important predictor of knowledge about Parkinson's disease.

Cognitive training interventions for dementia and mild cognitive impairment in Parkinson's disease

BACKGROUND

Approximately 60% to 80% of people with Parkinson's disease (PD) experience cognitive impairment that impacts on their quality of life. Cognitive decline is a core feature of the disease and can often present before the onset of motor symptoms. Cognitive training may be a useful non-pharmacological intervention that could help to maintain or improve cognition and quality of life for people with PD dementia (PDD) or PD-related mild cognitive impairment (PD-MCI).

OBJECTIVES

To determine whether cognitive training (targeting single or multiple domains) improves cognition in people with PDD and PD-MCI or other clearly defined forms of cognitive impairment in people with PD.

SEARCH METHODS

We searched the Cochrane Dementia and Cognitive Improvement Group Trials Register (8 August 2019), the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, CINAHL, and PsycINFO. We searched reference lists and trial registers, searched relevant reviews in the area and conference proceedings. We also contacted experts for clarifications on data and ongoing trials.

SELECTION CRITERIA

We included randomised controlled trials where the participants had PDD or PD-MCI, and where the intervention was intended to train general or specific areas of cognitive function, targeting either a single domain or multiple domains of cognition, and was compared to a control condition. Multicomponent interventions that also included motor or other elements were considered eligible.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles, abstracts, and full-text articles for inclusion in the review. Two review authors also independently undertook extraction of data and assessment of methodological quality. We used GRADE methods to assess the overall quality of the evidence.

MAIN RESULTS

Seven studies with a total of 225 participants met the inclusion criteria for this review. All seven studies compared the effects of a cognitive training intervention to a control intervention at the end of treatment periods lasting four to eight weeks. Six studies included people with PD living in the community. These six studies recruited people with single-domain (executive) or multiple-domain mild cognitive impairment in PD. Four of these studies identified participants with MCI using established diagnostic criteria, and two included both people with PD-MCI and people with PD who were not cognitively impaired. One study recruited people with a diagnosis of PD dementia who were living in long-term care settings. The cognitive training intervention in three studies targeted a single cognitive domain, whilst in four studies multiple domains of cognitive function were targeted. The comparison groups either received no intervention or took part in recreational activities (sports, music, arts), speech or language exercises, computerised motor therapy, or motor rehabilitation combined with recreational activity. We found no clear evidence that cognitive training improved global cognition. Although cognitive training was associated with higher scores on global cognition at the end of treatment, the result was imprecise and not statistically significant (6 trials, 178 participants, standardised mean difference (SMD) 0.28, 95% confidence interval (CI) -0.03 to 0.59; low-certainty evidence). There was no evidence of a difference at the end of treatment between cognitive training and control interventions on executive function (5 trials, 112 participants; SMD 0.10, 95% CI -0.28 to 0.48; low-certainty evidence) or visual processing (3 trials, 64 participants; SMD 0.30, 95% CI -0.21 to 0.81; low-certainty evidence). The evidence favoured the cognitive training group on attention (5 trials, 160 participants; SMD 0.36, 95% CI 0.03 to 0.68; low-certainty evidence) and verbal memory (5 trials, 160 participants; SMD 0.37, 95% CI 0.04 to 0.69; low-certainty evidence), but these effects were less certain in sensitivity analyses that excluded a study in which only a minority of the sample were cognitively impaired. There was no evidence of differences between treatment and control groups in activities of daily living (3 trials, 67 participants; SMD 0.03, 95% CI -0.47 to 0.53; low-certainty evidence) or quality of life (5 trials, 147 participants; SMD -0.01, 95% CI -0.35 to 0.33; low-certainty evidence). There was very little information on adverse events. We considered the certainty of the evidence for all outcomes to be low due to risk of bias in the included studies and imprecision of the results. We identified six ongoing trials recruiting participants with PD-MCI, but no ongoing trials of cognitive training for people with PDD.

AUTHORS' CONCLUSIONS

This review found no evidence that people with PD-MCI or PDD who receive cognitive training for four to eight weeks experience any important cognitive improvements at the end of training. However, this conclusion was based on a small number of studies with few participants, limitations of study design and execution, and imprecise results. There is a need for more robust, adequately powered studies of cognitive training before conclusions can be drawn about the effectiveness of cognitive training for people with PDD and PD-MCI. Studies should use formal criteria to diagnose cognitive impairments, and there is a particular need for more studies testing the efficacy of cognitive training in people with PDD.

Cognitive profiles and optimal cut-offs for routine cognitive tests in elderly individuals with Parkinson's disease, Parkinson's disease dementia, Alzheimer's disease, and normal cognition

AIM

The cognitive impairment seen in Parkinson's disease (PD) results in patient disability and reduced quality of life. However, using cognitive screening scales specific to PD in routine clinical practice is difficult because of limited time, resources, and skills. We studied the ability of routine cognitive tests to differentiate between Parkinson's disease dementia (PDD) and PD and among the neuropsychological profiles of elderly individuals with PD, PDD, Alzheimer's disease (AD), and normal cognition.

METHODS

This cross-sectional study involved 124 subjects. Subjects were 35 cognitively normal elderly and 37 elderly individuals with PD, 22 with PDD, and 30 with AD. All subjects were diagnosed by a specialist using standard criteria. Clinically relevant data and scores from the Montreal Cognitive Assessment and the Thai Mental State Examination were collected. Cognitive test scores were compared among groups. Receiver operating characteristic curves were constructed for a range of cut-off points to explore the sensitivity and specificity of the screening tools to detect PDD.

RESULTS

There were 74 female subjects (59.7%), and the average age of all subjects was 75.6 years. The median score on the modified Hoehn and Yahr scale was 2.5 in subjects with PD and 4 in those with PDD (P < 0.001). The cut-offs for differentiating PDD from PD were 25 on the Thai Mental State Examination and 14 on the Montreal Cognitive Assessment. The sensitivity of the Thai Mental State Examination was 78.4%, and the specificity was 66.7% (area under the curve: 0.828). The sensitivity of the Montreal Cognitive Assessment was 81.1%, and the specificity was 75% (area under the curve: 0.876). There was a significant difference in the memory and language subdomains between AD and PDD (P < 0.05).

CONCLUSIONS

The cut-offs used to differentiate PDD from PD were not the same as routine cut-offs in distinguishing AD from normal elderly. The cognitive profile deficit in PDD differed from that in AD. Interpretations of positive screenings test should take this finding into consideration.

Methods and applications of CRISPR/Cas system for genome editing in stem cells

Genome editing technology holds great promise for genome manipulation and gene therapy. While widespread utilization, genome editing has been used to unravel the roles of specific genes in differentiation and pluripotency of stem cells, and reinforce the stem cell-based applications. In this review, we summarize the advances of genome editing technology, as well as the derivative technologies from CRISPR/Cas system, which show tremendous potential in various fields. We also highlight the key findings in the studies of stem cells and regeneration by genome editing technology.

A quick test of cognitive speed can predict development of dementia in Parkinson's disease

Parkinson’s disease (PD) patients frequently develop cognitive impairment. There is a need for brief clinical assessments identifying PD patients at high risk of progressing to dementia. In this study, we look into predicting dementia in PD and underlying structural and functional correlates to cognitive decline in PD. We included 175 patients with PD, 30 with PD dementia, 51 neurologically healthy controls and 121 patients with Alzheimer’s disease (AD) from Skane University Hospital, BIOFINDER cohorts. All underwent cognitive tests, including MMSE, 10-word list delayed recall (ADAS-cog), A Quick Test of cognitive speed (AQT), Letter S fluency, Clock Drawing Test (CDT) and pentagon copying. In non-demented patients with PD, abnormal AQT and CDT results predicted an increased risk of subsequent development of dementia (hazard ratio 2.2 for both). When comparing the cognitive profile between PD and AD, decreased performance on AQT, which measures attention and processing speed, was more typical in PD. Lastly, we investigated the underlying structural and functional correlates for the PD-specific test AQT with magnetic resonance imaging. In PD patients, decreased performance on AQT was associated with i) cortical thinning in temporoparietal regions, ii) changes in diffusion MRI, especially in the cingulum tract, and iii) decreased functional connectivity in posterior brain networks.

Multilevel Impacts of Iron in the Brain: The Cross Talk between Neurophysiological Mechanisms, Cognition, and Social Behavior

Iron is a critical element for most organisms, which plays a fundamental role in the great majority of physiological processes. So much so, that disruption of iron homeostasis has severe multi-organ impacts with the brain being particularly sensitive to such modifications. More specifically, disruption of iron homeostasis in the brain can affect neurophysiological mechanisms, cognition, and social behavior, which eventually contributes to the development of a diverse set of neuro-pathologies. This article starts by exploring the mechanisms of iron action in the brain and follows with a discussion on cognitive and behavioral implications of iron deficiency and overload and how these are framed by the social context. Subsequently, we scrutinize the implications of the disruption of iron homeostasis for the onset and progression of psychosocial disorders. Lastly, we discuss the links between biological, psychological, and social dimensions and outline potential avenues of research. The study of these interactions could ultimately contribute to a broader understanding of how individuals think and act under physiological and pathophysiological conditions.

Regional changes in the type 1 cannabinoid receptor are associated with cognitive dysfunction in Parkinson's disease

PURPOSE

The endocannabinoid system plays a regulatory role in a number of physiological functions, including motor control but also mood, emotion, and cognition. A number of preclinical studies in Parkinson's disease (PD) models demonstrated that modulating the type 1 cannabinoid receptor (CB₁R) may improve motor symptoms and components of cognitive processing. However, the relation between CB₁R, cognitive decline and behavioral symptoms has not been investigated in PD patients so far. The aim of this study was to examine whether CB₁R availability is associated with measures of cognitive and behavioral function in PD patients.

METHODS

Thirty-eight PD patients and ten age- and gender-matched controls underwent a [¹⁸F]MK-9470 PET scan to assess CB₁R availability, as well as volumetric MR imaging. Neuropsychological symptoms were evaluated using an extensive cognitive and behavioral battery covering the five cognitive domains, depression, anxiety, apathy, and psychiatric complications, and were correlated to CB₁R availability using vowel-wise regression analysis (P < 0.05, corrected for familywise error).

RESULTS

PD patients with poorer performance in episodic memory, executive functioning, speed and mental flexibility (range P 0.003-0.03) showed lower CB₁R availability in predominantly the midcingulate cortex and middle to superior frontal gyrus (T_peak-level > 4.0). Also, PD patients with more severe visuospatial dysfunction showed decreased CB₁R availability in the precuneus, midcingulate, supplementary motor cortex, inferior orbitofrontal gyrus and thalamus (T_peak-level = 5.5). These correlations were not related to cortical gray matter atrophy. No relationship was found between CB₁R availability and mood or behavioral symptom scores.

CONCLUSIONS

Decreased CB₁R availability in the prefrontal and midcingulate cortex in PD patients is strongly correlated with disturbances in executive functioning, episodic memory, and visuospatial functioning. Further investigation of regional CB1R expression in groups of PD patients with mild cognitive impairment or dementia is warranted in order to further investigate the role of CB1R expression in different levels of cognitive impairment in PD.