Approach to Cognitive Impairment in Parkinson's Disease

The effect of anticholinergic drugs on cognition of patients with Parkinson's disease: a cohort study from the Egyptian population

BACKGROUND

Cognitive dysfunction is a non-motor manifestation of Parkinson's disease (PD). We aimed to determine the frequency and patterns of cognitive dysfunction in treated patients with PD and their predictors.

RESEARCH DESIGN AND METHODS

This study included 80 patients (male = 48; female = 32) and 30 healthy individuals. They underwent neuropsychiatric evaluations. Measurements included Beck's depression inventory - II (BDI-II), mini-mental state examination (MMSE) and Montreal cognitive assessment (MoCA).

RESULTS

Patients had mean age of 55.56 ± 9.06 yrs, duration of PD of 4.86 ± 2.71 yrs and Hoehn and Yahr Scoring of 2.19 ± 0.89. They were on levodopa/carbidopa therapy and adjuvant therapy with benztropine mesylate, an anticholinergic drug, (n = 51) or amantadine sulfate, a dopaminergic drug, (n = 29). Sixteen (20%) had moderate depressive symptoms. Mild and moderate cognitive impairments were reported in 38.8% and 28.8% (by MMSE) and 46.3% and 31.3% (by MoCA). Patients had lower global cognitive scoring (p = 0.0001) and scorings of different cognitive functions (naming, attention, language, abstraction, memory and orientation) than controls. Patients treated with benztropine had lower cognition than with amantadine. Correlation analyses showed that lower cognition was only associated with chronic PD and its treatment (p = 0.0001).

CONCLUSIONS

Cognitive dysfunction is common with PD (77.5%) particularly with anticholinergic drugs. De-prescription of anticholinergics is recommended for patients with PD.

Review of Current Clinical Options for the Management of Behavioral and Psychological Symptoms of Dementia

Dementia is a disease most prevalent in the older adult population. The cognitive symptoms of dementia include impairments in problem-solving, memory, and language. Some patients experience noncognitive symptoms in addition to the cognitive symptoms of dementia. These noncognitive symptoms are called behavioral and psychological symptoms of dementia or BPSD. The primary objective of our study was to examine the therapeutic options, guidelines, and clinical considerations for the management of BPSD. The existing literature about BPSD was reviewed with searches in PubMed, MEDLINE, and online search platforms. Dysregulation of neurotransmission involving acetylcholine, dopamine, and serotonin has been shown to cause behavioral and psychological symptoms of Alzheimer's disease. BPSD can include hallucinations, agitation, delusions, anxiety, apathy, abnormal body movements, irritability, depression, disinhibition, and sleep or appetite changes. Pharmacologic therapies used in the treatment of BPSD include antidepressants, antipsychotics, anxiolytics, and anticonvulsants. Treatment can be tailored to the specific noncognitive symptoms that are experienced. The use of these agents may be limited based on recommendations from the Beers Criteria®, STOPP criteria, treatment guidelines, and FDA warnings.

Androgen effects on mesoprefrontal dopamine systems in the adult male brain

Epidemiological data show that males are more often and/or more severely affected by symptoms of prefrontal cortical dysfunction in schizophrenia, Parkinson's disease and other disorders in which dopamine circuits associated with the prefrontal cortex are dysregulated. This review focuses on research showing that these dopamine circuits are powerfully regulated by androgens. It begins with a brief overview of the sex differences that distinguish prefrontal function in health and prefrontal dysfunction or decline in aging and/or neuropsychiatric disease. This review article then spotlights data from human subjects and animal models that specifically identify androgens as potent modulators of prefrontal cortical operations and of closely related, functionally critical measures of prefrontal dopamine level or tone. Candidate mechanisms by which androgens dynamically control mesoprefrontal dopamine systems and impact prefrontal states of hypo- and hyper-dopaminergia in aging and disease are then considered. This is followed by discussion of a working model that identifies a key locus for androgen modulation of mesoprefrontal dopamine systems as residing within the prefrontal cortex itself. The last sections of this review critically consider the ways in which the organization and regulation of mesoprefrontal dopamine circuits differ in the adult male and female brain, and highlights gaps where more research is needed.

NIR-II light therapy improves cognitive performance in MPTP induced Parkinson's disease rat models: A preliminary experimental study

Cognitive impairment is an important component of non motor symptoms in Parkinson's disease (PD), and if not addressed in a timely manner, it can easily progress to dementia. However, no effective method currently exists to completely prevent or reverse cognitive impairment associated with PD. We therefore aimed to investigate the therapeutic effect of near-infrared region II light (NIR-II) region illumination on cognitive impairment in PD through behavioral experiments (water maze and rotary rod) and multiple fluorescence immunohistochemistry techniques. The 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)-induced group was compared with the MPTP- untreated rat group, showing a significant reduction in escape latency and significant increase in the fall latency in the MPTP-treated group. The horizontal analysis results indicated that NIR-II phototherapy improved the learning and cognitive abilities as well as coordination and balance abilities of rats. Post-treatment, the MPTP rats showed significantly shortened, escape latency, prolonged target quadrant residence time, and prolonged fall latency compared with pre-treatment. The longitudinal analysis results reaffirmed that NIR-II phototherapy improved the learning and cognitive abilities as well as coordination and balance abilities of rats. The multiple fluorescence immunohistochemistry analysis trend plot showed that the activated microglia and astrocytes in the hippocampus were highest in MPTP-induced PD untreated group, moderate in MPTP-induced PD treatment group, and lowest in the control group. Our data indicates that NIR-II illumination improves learning and cognitive impairment as well as coordination and balance abilities in PD rats by downregulating the activation of microglia and astrocytes in the hippocampus.

Deciphering the dual role of N-methyl-D-Aspartate receptor in postoperative cognitive dysfunction: A comprehensive review

Postoperative cognitive dysfunction (POCD) is a common complication following surgery, adversely impacting patients' recovery, increasing the risk of negative outcomes, prolonged hospitalization, and higher mortality rates. The N-methyl-D-aspartate (NMDA) receptor, crucial for learning, memory, and synaptic plasticity, plays a significant role in the development of POCD. Various perioperative factors, including age and anesthetic use, can reduce NMDA receptor function, while surgical stress, inflammation, and pain may lead to its excessive activation. This review consolidates preclinical and clinical research to explore the intricate relationship between perioperative factors affecting NMDA receptor functionality and the onset of POCD. It discusses the influence of aging, anesthetic administration, perioperative injury, pain, and inflammation on the NMDA receptor-related pathophysiology of POCD. The comprehensive analysis presented aims to identify effective treatment targets for POCD, contributing to the improvement of patient outcomes post-surgery.

Risk of impairment in cognitive instrumental activities of daily living for sexual and gender minority adults with reported Parkinson's disease

Objective: To investigate the risk of impairment in cognitive instrumental activities of daily living (IADL) for people with Parkinson's (PwP) identifying as sexual and/or gender minorities (SGM). Method: Data were obtained from Fox Insight, an online, longitudinal study with self/informant-report questionnaires from PwP and people without Parkinson's. Groups consisted of PwP without cognitive IADL impairment at baseline, identifying as (1) SGM with female sex assigned at birth (SGM-F, n = 75); (2) cisgender, heterosexual with female sex assigned at birth (CH-F, n = 2046); (3) SGM with male sex assigned at birth (SGM-M, n = 84); (4) cisgender, heterosexual with male sex assigned at birth (CH-M, n = 2056). Impairment in cognitive IADL was based on Penn Parkinson's Daily Activities Questionnaire-15 (PDAQ-15). Group differences for PDAQ-15 and impairment likelihood during follow-up were assessed with unadjusted models and adjusting for variables that differed between the groups. Results: SGM-F were the youngest at Parkinson's diagnosis; SGM-M had the lowest PDAQ-15 at baseline (p ≤ .014 for all). Scores declined more for males than females in unadjusted and adjusted models (p < .001 for both). In unadjusted models, SGM-M had a higher impairment risk than PwP identifying as cisgender and heterosexual (p ≤ .018). In adjusted models, females had a lower impairment risk than males (p < .001). Age, education, and discrimination level were significant moderators (p < .001 for all). Conclusions: SGM-M can be at a higher risk for impairment in cognitive IADL, associated with social determinants. Female sex assigned at birth may be associated with a lower level of impairment risk, although this advantage can disappear with social determinants.

Acupuncture for the Treatment of Neuropsychiatric Symptoms in Parkinson's Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Neuropsychiatric symptoms (NPSs) of Parkinson's disease (PD) have received increasing attention, but effective treatment options remain limited. Acupuncture may have clinical benefits for NPSs in PD patients, but high-quality evidence supporting this possibility still needs to be discovered. Therefore, we conducted a meta-analysis to evaluate the effect of acupuncture treatment on NPSs in PD patients.

METHODS

Randomized controlled trials (RCTs) of acupuncture treatment for PD retrieved from the following electronic databases: PubMed, Embase, Cochrane Library, Web of Science, and Scopus, were used to evaluate NPSs of PD patients. The Cochrane Intervention System Evaluation Manual assessed the methodological quality.

RESULTS

A total of 13 RCTs involving 719 patients were included. The results showed that compared with medication alone or sham acupuncture, acupuncture improved sleep quality in PD patients, with Parkinson's Disease Sleep Scale (PDSS) [standardized mean difference (SMD)= 0.48, 95% confidence interval (CI)= 0.242 to 0.793, P = 0.001]. The I scores and total scores on Unified Parkinson's Disease Rating Scale (UPDRS) indicated acupuncture treatment was effective (SMD=-0.66, 95%CI=-0.66 to -0.18, P = 0.042; SMD=-0.77, 95%CI=-1.31 to -0.23, P = 0.005). Results of the Epworth Sleepiness Scale (ESS) and Parkinson's Disease Questionnaire-39 (PDQ-39) showed no statistically significant differences (SMD=-0.27, 95%CI=-0.08 to 0.62, P = 0.128; SMD=-0.20, 95%CI=-0.42 to 0.01, P = 0.554). Anxiety and depression research had no significant differences due to the excessive inter-study bias.

CONCLUSION

Acupuncture treatment can improve sleep quality, psychological and behavioral alterations, and the overall condition of PD patients. However, the study revealed no significant positive intervention effects on anxiety, depression, and quality of life, underscoring the necessity for continued research to elucidate these domains' intricacies and develop productive therapeutic approaches.

A review of the neurotransmitter system associated with cognitive function of the cerebellum in Parkinson's disease

The dichotomized brain system is a concept that was generalized from the 'dual syndrome hypothesis' to explain the heterogeneity of cognitive impairment, in which anterior and posterior brain systems are independent but partially overlap. The dopaminergic system acts on the anterior brain and is responsible for executive function, working memory, and planning. In contrast, the cholinergic system acts on the posterior brain and is responsible for semantic fluency and visuospatial function. Evidence from dopaminergic/cholinergic imaging or functional neuroimaging has shed significant insight relating to the involvement of the cerebellum in the cognitive process of patients with Parkinson's disease. Previous research has reported evidence that the cerebellum receives both dopaminergic and cholinergic projections. However, whether these two neurotransmitter systems are associated with cognitive function has yet to be fully elucidated. Furthermore, the precise role of the cerebellum in patients with Parkinson's disease and cognitive impairment remains unclear. Therefore, in this review, we summarize the cerebellar dopaminergic and cholinergic projections and their relationships with cognition, as reported by previous studies, and investigated the role of the cerebellum in patients with Parkinson's disease and cognitive impairment, as determined by functional neuroimaging. Our findings will help us to understand the role of the cerebellum in the mechanisms underlying cognitive impairment in Parkinson's disease.

Smartphone-Based Cognitive Telerehabilitation: A Usability and Feasibility Study Focusing on Mild Cognitive Impairment

The implementation of cognitive health apps in patients with mild cognitive impairment (MCI) is challenging because of their cognitive, age, and other clinical characteristics. In this project, we aimed to evaluate the usability and feasibility of the Rehastart app tested in MCI patients. Eighteen subjects affected by MCI due to neurodegenerative disorders (including Parkinson's disease, multiple sclerosis, and amnestic/multidomain MCI) and eighteen healthcare professionals were recruited to this study. Patients were registered on the app by clinicians and they were assigned a protocol of specific cognitive exercises. The recruitment was conducted in the period between March and June 2023. The trial testing of the app consisted of three sessions per week for three weeks, with each session lasting about 30 min. After three weeks, the participants as well as medical personnel were invited to rate the usability and feasibility of the Rehastart mobile application. The instruments employed to evaluate the usability and feasibility of the app were the System Usability Scale (SUS), The Intrinsic Motivation Inventory (IMI) and the Client Satisfaction Questionnaire (CSQ). We did not find statistically significant differences on the SUS (p = 0.07) between healthcare professionals and patients. In addition, we found promising results on subscales of the Intrinsic Motivation Inventory, suggesting high levels of interest and enjoyment when using the Rehastart app. Our study demonstrated that smartphone-based telerehabilitation could be a suitable tool for people with MCI due to neurodegenerative disorders, since the Rehastart app was easy to use and motivating for both patients and healthy people.

Alpha-Synuclein Pre-Formed Fibrils Injected into Prefrontal Cortex Primarily Spread to Cortical and Subcortical Structures

BACKGROUND

Parkinson's disease dementia (PDD) and dementia with Lewy bodies (DLB) are characterized by diffuse spread of alpha-synuclein (α-syn) throughout the brain. Patients with PDD and DLB have a neuropsychological pattern of deficits that include executive dysfunction, such as abnormalities in planning, timing, working memory, and behavioral flexibility. The prefrontal cortex (PFC) plays a major role in normal executive function and often develops α-syn aggregates in DLB and PDD.

OBJECTIVE

To investigate the long-term behavioral and cognitive consequences of α-syn pathology in the cortex and characterize pathological spread of α-syn.

METHODS

We injected human α-syn pre-formed fibrils into the PFC of wild-type male mice. We then assessed the behavioral and cognitive effects between 12- and 21-months post-injection and characterized the spread of pathological α-syn in cortical, subcortical, and brainstem regions.

RESULTS

We report that PFC PFFs: 1) induced α-syn aggregation in multiple cortical and subcortical regions with sparse aggregation in midbrain and brainstem nuclei; 2) did not affect interval timing or spatial learning acquisition but did mildly alter behavioral flexibility as measured by intraday reversal learning; and 3) increased open field exploration.

CONCLUSIONS

This model of cortical-dominant pathology aids in our understanding of how local α-syn aggregation might impact some symptoms in PDD and DLB.

Potential Therapeutic Approach using Aromatic l-amino Acid Decarboxylase and Glial-derived Neurotrophic Factor Therapy Targeting Putamen in Parkinson's Disease

Parkinson's disease (PD) is a neurodegenerative illness characterized by specific loss of dopaminergic neurons, resulting in impaired motor movement. Its prevalence is twice as compared to the previous 25 years and affects more than 10 million individuals. Lack of treatment still uses levodopa and other options as disease management measures. Treatment shifts to gene therapy (GT), which utilizes direct delivery of specific genes at the targeted area. Therefore, the use of aromatic L-amino acid decarboxylase (AADC) and glial-derived neurotrophic factor (GDNF) therapy achieves an effective control to treat PD. Patients diagnosed with PD may experience improved therapeutic outcomes by reducing the frequency of drug administration while utilizing provasin and AADC as dopaminergic protective therapy. Enhancing the enzymatic activity of tyrosine hydroxylase (TH), glucocorticoid hormone (GCH), and AADC in the striatum would be useful for external L-DOPA to restore the dopamine (DA) level. Increased expression of glutamic acid decarboxylase (GAD) in the subthalamic nucleus (STN) may also be beneficial in PD. Targeting GDNF therapy specifically to the putaminal region is clinically sound and beneficial in protecting the dopaminergic neurons. Furthermore, preclinical and clinical studies supported the role of GDNF in exhibiting its neuroprotective effect in neurological disorders. Another Ret receptor, which belongs to the tyrosine kinase family, is expressed in dopaminergic neurons and sounds to play a vital role in inhibiting the advancement of PD. GDNF binding on those receptors results in the formation of a receptor-ligand complex. On the other hand, venous delivery of recombinant GDNF by liposome-based and encapsulated cellular approaches enables the secure and effective distribution of neurotrophic factors into the putamen and parenchyma. The current review emphasized the rate of GT target GDNF and AADC therapy, along with the corresponding empirical evidence.

Longitudinal Neuropsychological Assessment of Symptomatic Edema after Subthalamic Nucleus Deep Brain Stimulation Surgery: A Case Series Study

Severe non-infectious or non-haemorrhagic brain edema surrounding the electrode represents a rare complication of subthalamic nucleus deep brain stimulation (STN-DBS) surgery. The aim of this study is to report three patients with advanced Parkinson's Disease (PD) who developed symptomatic brain edema after STN-DBS surgery treated with intravenous steroids with a specific profile of reversible cognitive alterations. Patients were both assessed with a comprehensive neuropsychological battery including attention, memory, visuo-spatial and executive tasks. They were also briefly assessed for emotional and behavioural alterations, and for possible limitations in the activities of daily living. Normative data for an Italian population were available for all neuropsychological tests. The patients were firstly assessed before the surgery (baseline) as soon as they became symptomatic for the post-surgery edema and a few more times in follow-up up to ten months. In all patients we observed the resolution of cognitive deficits within six months after surgery with the corresponding reabsorption of edema at brain CT scans. The appearance of post-DBS edema is a fairly frequent and clinically benign event. However, in some rare cases it can be very marked and lead to important clinical-albeit transient-disturbances. These events can compromise, at least from a psychological point of view, the delicate path of patients who undergo DBS and can prolong the post-operative hospital stay. In this setting it could be helpful to perform a brain CT scan in 2-3 days with the aim of detecting the early appearance of edema and treating it before it can constitute a relevant clinical problem.

Pathological Correlates of Cognitive Decline in Parkinson's Disease: From Molecules to Neural Networks

Parkinson's disease (PD) is a progressive neurodegenerative disorder caused by the death of dopaminergic neurons in the substantia nigra and appearance of protein aggregates (Lewy bodies) consisting predominantly of α-synuclein in neurons. PD is currently recognized as a multisystem disorder characterized by severe motor impairments and various non-motor symptoms. Cognitive decline is one of the most common and worrisome non-motor symptoms. Moderate cognitive impairments (CI) are diagnosed already at the early stages of PD, usually transform into dementia. The main types of CI in PD include executive dysfunction, attention and memory decline, visuospatial impairments, and verbal deficits. According to the published data, the following mechanisms play an essential role demonstrates a crucial importance in the decline of the motor and cognitive functions in PD: (1) changes in the conformational structure of transsynaptic proteins and protein aggregation in presynapses; (2) synaptic transmission impairment; (3) neuroinflammation (pathological activation of the neuroglia); (4) mitochondrial dysfunction and oxidative stress; (5) metabolic disorders (hypometabolism of glucose, dysfunction of glycolipid metabolism; and (6) functional rearrangement of neuronal networks. These changes can lead to the death of dopaminergic cells in the substantia nigra and affect the functioning of other neurotransmitter systems, thus disturbing neuronal networks involved in the transmission of information related to the regulation of motor activity and cognitive functions. Identification of factors causing detrimental changes in PD and methods for their elimination will help in the development of new approaches to the therapy of PD. The goal of this review was to analyze pathological processes that take place in the brain and underlie the onset of cognitive disorders in PD, as well as to describe the impairments of cognitive functions in this disease.

Association between PM2.5 exposure and risk of Parkinson's disease in individuals with chronic obstructive pulmonary disease in Taiwan: a nested case-control study

OBJECTIVES

This cohort study investigated the correlation between Parkinson's disease (PD) risk and chronic obstructive pulmonary disease (COPD) risk under particulate matter with an aerodynamic diameter ≤2.5 μm (PM2.5) exposure.

METHODS

Data from the National Health Research Institutes of Taiwan were used in this study. The Environmental Protection Administration of Taiwan established an air quality monitoring network for monitoring Taiwan's general air quality. COPD was indicated by at least 3 outpatient records and 1 hospitalization for COPD. After the implementation of age, sex, and endpoint matching at a 1:4 ratio, 137 patients and 548 patients were included in the case group and control group, respectively. Based on the 2005 World Health Organization (WHO) standards, monthly air particle concentration data were classified into the following 4 groups in analyses of exposure-response relationships: normal level, and 1.0, 1.5, and 2.0 times the WHO level ([concentration ≥2]×25 μg/m3×number of exposure months).

RESULTS

A multivariate logistic regression revealed that the 1.0 and 1.5 WHO level groups did not significantly differ from the normal level group, but the 2.0 WHO level did (odds ratio, 4.091; 95% confidence interval, 1.180 to 14.188; p=0.038).

CONCLUSIONS

Elevated PM2.5 concentrations were significantly correlated with an increased risk of PD among patients with COPD. Furthermore, exposure to high PM2.5 levels can further increase the risk of PD.

Cognitive Impairment in Parkinson's Disease: An Updated Overview Focusing on Emerging Pharmaceutical Treatment Approaches

Cognitive impairment in patients with Parkinson's disease (PD) is one of the commonest and most disabling non-motor manifestations during the course of the disease. The clinical spectrum of PD-related cognitive impairment includes subjective cognitive decline (SCD), mild cognitive impairment (MCI) and PD dementia (PDD). As the disease progresses, cognitive decline creates a significant burden for the family members and/or caregivers of patients with PD, and has a great impact on quality of life. Current pharmacological treatments have demonstrated partial efficacy and failed to halt disease progression, and novel, effective, and safe therapeutic strategies are required. Accumulating preclinical and clinical evidence shows that several agents may provide beneficial effects on patients with PD and cognitive impairment, including ceftriaxone, ambroxol, intranasal insulin, nilotinib, atomoxetine, mevidalen, blarcamesine, prasinezumab, SYN120, ENT-01, NYX-458, GRF6021, fosgonimeton, INT-777, Neuropeptide S, silibinin, osmotin, cordycepin, huperzine A, fibroblast growth factor 21, Poloxamer 188, ginsenoside Rb1, thioredoxin-1, tangeretin, istradefylline and Eugenia uniflora. Potential underlying mechanisms include the inhibition of a-synuclein aggregation, the improvement of mitochondrial function, the regulation of synaptic plasticity, an impact on the gut-brain axis, the modulation of neuroinflammation and the upregulation of neurotrophic factors, as well as cholinergic, dopaminergic, serotoninergic and norepinephrine neurotransmission. In this updated overview, we aim to cover the clinical aspects of the spectrum of PD-related cognitive impairment and discuss recent evidence on emerging treatment approaches that are under investigation at a preclinical and clinical level. Finally, we aim to provide additional insights and propose new ideas for investigation that may be feasible and effective for the spectrum of PD-related cognitive impairment.

Paradigm Shift: Multiple Potential Pathways to Neurodegenerative Dementia

Neurodegenerative dementia can result from multiple underlying abnormalities, including neurotransmitter imbalances, protein aggregation, and other neurotoxic events. A major complication in identifying effective treatment targets is the frequent co-occurrence of multiple neurodegenerative processes, occurring either in parallel or sequentially. The path towards developing effective treatments for Alzheimer's disease (AD) and other dementias has been relatively slow and until recently has focused on disease symptoms. Aducanumab and lecanemab, recently approved by the FDA, are meant to target disease structures but have only modest benefit on symptom progression and remain unproven in reversing or preventing dementia. A third, donanemab, appears more promising but awaits FDA approval. Ongoing trials include potential cognition enhancers, new combinations of known drugs for synergistic effects, prodrugs with less toxicity, and increasing interest in drugs targeting neuroinflammation or microbiome. Scientific and technological advances offer the opportunity to move in new therapy directions, such as modifying microglia to prevent or suppress underlying disease. A major challenge, however, is that underlying comorbidities likely influence the effectiveness of therapies. Indeed, the full range of comorbidity, today only definitively identified postmortem, likely contributes to failed clinical trials and overmedication of older adults, since it is difficult to exclude (during life) people unlikely to respond. Our current knowledge thus signals that a paradigm shift towards individualized and multimodal treatments is necessary to effectively advance the field of dementia therapeutics.

Detecting Subtle Cognitive Impairment in Patients with Parkinson's Disease and Normal Cognition: A Novel Cognitive Control Challenge Task (C3T)

Patients with Parkinson's disease (PD) often show early deficits in cognitive control, with primary difficulties in flexibility and relatively intact stable representations. The aim of our study was to assess executive function using an ecologically valid approach that combines measures of stability and flexibility. Fourteen patients without cognitive deficits and sixteen comparable control subjects completed a standardized neuropsychological test battery and a newly developed cognitive control challenge task (C3T). We found that the accuracy of C3T performance decreased with age in healthy participants and remained impaired in PD patients regardless of age. In addition, PD patients showed significantly lower overall performance for cognitive control tasks than healthy controls, even when they scored in the normal range on standardized neuropsychological tests. PD Patients responded significantly faster than healthy control subjects regarding flexible cognitive control tasks due to their impulsivity. Correlations showed that the C3T task targets multiple cognitive systems, including working memory, inhibition, and task switching, providing a reliable measure of complex cognitive control. C3T could be a valuable tool for characterizing cognitive deficits associated with PD and appears to be a more sensitive measure than standardized neuropsychological tests. A different assessment approach could potentially detect early signs of the disease and identify opportunities for early intervention with neuroprotective therapies.

A systematic review and network meta-analysis comparing various non-pharmacological treatments for older people with mild cognitive impairment

BACKGROUND AND OBJECTIVE

Non-pharmacological therapy appeared to alleviate Mild Cognitive Impairment (MCI) symptoms and signs, according to systematic studies. This network meta-analysis aimed to assess the impact of non-pharmacological therapies on improving cognition in individuals with MCI and identified the most effective intervention.

METHODS

We reviewed six databases in search of potentially relevant studies of non-pharmacological therapies such as Physical exercise (PE), Multidisciplinary intervention (MI), Musical therapy (MT), Cognitive training (CT), Cognitive stimulation (CS), Cognitive rehabilitation (CR)，Art therapy (AT), general psychotherapy or interpersonal therapy (IPT), and Traditional Chinese Medicine (TCM) (such as acupuncture therapy, massage, auricular-plaster and other related systems) and others. Excluded the literature such as missing full text, missing search results, or no reporting specific values and combined with the inclusion criteria and exclusion criteria in this article, the literature ultimately included in the analysis addressed the following seven non-drug therapies PE, MI, MT, CT, CS, CR, AT. Mini-mental state evaluation paired meta-analyses were undertaken by taking weighted average mean differences with confidence intervals (CI) of 95%. The network meta-analysis was conducted to compare various therapies.

RESULTS

A total of 39 randomized controlled trials, including two three-arm studies, with 3157 participants were included. PE was most likely to be the most effective intervention to slow down the cognitive ability of patients (SMD = 1.34, 95%CI: 0.80, 1.89). CS and CR had no significant effect on cognitive ability.

CONCLUSIONS

The non-pharmacological therapy had the potential to greatly promote the cognitive ability of the adult population with MCI. PE had the best chance of being the best non-pharmacological therapy. Due to the limited sample size, substantial variability among different study designs, and the potential for bias, the results should be regarded with caution. Our findings should be confirmed by future multi-center randomized controlled, high-quality large-scale studies.

Alpha-synuclein pre-formed fibrils injected into prefrontal cortex primarily spread to cortical and subcortical structures and lead to isolated behavioral symptoms

Parkinson's disease dementia (PDD) and dementia with Lewy bodies (DLB) are characterized by diffuse spread of alpha-synuclein (α-syn) throughout the brain. Patients with PDD and DLB have a neuropsychological pattern of deficits that include executive dysfunction, such as abnormalities in planning, timing, working memory, and behavioral flexibility. The prefrontal cortex (PFC) plays a major role in normal executive function and often develops α-syn aggregates in DLB and PDD. To investigate the consequences of α-syn pathology in the cortex, we injected human α-syn pre-formed fibrils into the PFC of wildtype mice. We report that PFC PFFs: 1) induced α-syn aggregation in multiple cortical and subcortical regions with sparse aggregation in midbrain and brainstem nuclei; 2) did not affect interval timing or spatial learning acquisition but did mildly alter behavioral flexibility as measured by intraday reversal learning; 3) increased open field exploration; and 4) did not affect susceptibility to an inflammatory challenge. This model of cortical-dominant pathology aids in our understanding of how local α-syn aggregation might impact some symptoms in PDD and DLB.

An Update on Peripheral Blood Extracellular Vesicles as Biomarkers for Parkinson's Disease Diagnosis

Parkinson's disease (PD) is the world's second primary neurodegenerative disease, and the diagnosis and treatment of PD have become mainstream research. Over the past decades, several studies have identified potential biomarkers for diagnosing PD. Among them, extracellular vesicles (EVs) can carry specific biomarkers reflecting the physiological and pathological state of the body. Due to the blood-brain barrier (BBB) limitation, peripheral blood is limited in diagnosing neurodegenerative diseases. With the increasing research on EVs, their ability to pass through BBB indicated that peripheral blood could depict disease status like cerebrospinal fluid (CSF). Peripheral blood is a clinically available sample and has recently been widely used by researchers in various studies. In this review, we summarized previous studies on PD diagnosis biomarkers in peripheral blood EVs and evaluated their diagnostic value. Some EV surface markers were also described, which can extract EVs from specific cell origins. In addition, the combination of several biomarkers demonstrated good diagnostic performance in PD diagnosis compared with a single biomarker, suggesting the focus of future research.

Plasma Soluble ST2 Levels Are Higher in Neurodegenerative Disorders and Associated with Poorer Cognition

BACKGROUND

Suppressor of tumorgenicity 2 (ST2) is highly expressed in brain tissue and is a receptor for interleukin 33 (IL-33). ST2 exists in two forms, a transmembrane receptor (ST2L) and a soluble decoy receptor (sST2). IL-33 binds to ST2L, triggering downstream signaling pathways involved in amyloid plaque clearance. Conversely, sST2 binds competitively to IL-33, attenuating its neuroprotective effects. High sST2 levels have been reported in mild cognitive impairment (MCI) and Alzheimer's disease (AD), suggesting that the IL-33/ST2 signaling pathway may be implicated in neurodegenerative diseases.

OBJECTIVE

To investigate plasma sST2 levels in controls and patients with MCI, AD, frontotemporal dementia (FTD), and Parkinson's disease (PD).

METHODS

Plasma sST2 levels were measured using ELISA in 397 subjects (91 HC, 46 MCI, 38 AD, 28 FTD, and 194 PD). Cerebrospinal fluid (CSF) levels of sST2 were measured in 22 subjects. Relationship between sST2 and clinical outcomes were analyzed.

RESULTS

Plasma sST2 levels were increased across all disease groups compared to controls, with highest levels seen in FTD followed by AD and PD. Dementia patients with higher sST2 had lower cross-sectional cognitive scores in Frontal Assessment Battery and Digit Span Backward. At baseline, PD-MCI patients had higher sST2, associated with worse attention. In the longitudinal PD cohort, higher sST2 significantly associated with decline in global cognition and visuospatial domains. Plasma sST2 levels correlated with CSF sST2 levels.

CONCLUSION

Plasma sST2 is raised across neurodegenerative diseases and is associated with poorer cognition. Higher baseline sST2 is a potential biomarker of disease severity in neurodegeneration.

Outcome of visuospatial dysfunction assessment in patients with Parkinson's disease using mobile application software

Background

Visuospatial dysfunction and cognitive impairment are common in Parkinson's disease (PD), which draw increasing attention in the current literature. But clinicians still lack rapid, effective and unified cognitive battery for visuospatial assessment.

Objective

A new approach was studied to explore the feasibility of using mobile application software (APP) to evaluate visuospatial dysfunction in patients with PD and compared with traditional assessment tools. We aimed to verify the threshold score of the APP for early diagnosis.

Materials and methods

A total of 41 patients with PD underwent assessments using several test modules including Digit Symbol Test (DST), Visual Organization Test (VOT), Facial Recognition Test (FRT), Vocabulary Memory Test (VMT) of this APP, as well as Clock Drawing Test (CDT), Cube Copying Test (CCT) and the Mini-Mental State Examination (MMSE) for comparison. Among the 41 PD patients, 30 individuals were found to have visuospatial dysfunction based on CDT score < 5 and CCT score of<18 while the remaining 11 patients served as control.

Results

There were statistically significant differences in DST, VOT, and FRT scores (all p ≤ 0.001 for group comparisons). DST, VOT, and FRT-1 were significantly correlated with MMSE, CDT and CCT and the correlations were moderate or fairly strong. For visuospatial dysfunction diagnosis, all the areas under curves (AUC) of DST, VOT, and FRT-1 were statistically significant (p < 0.0001, p = 0.0002, and p = 0.0002, respectively). The estimates and 95% confidence intervals of AUC were 0.8303 (0.6868, 0.9739), 0.8045 (0.6423, 0.9668), and 0.7833 (0.6344, 0.9322), respectively. Their cut-off points for visuospatial dysfunction were 26, 17, and 19, respectively. After dichotomization by the cut-off points, DST had high sensitivity of 96.67% while VOT and FRT-1 had high specificity of 81.82 and 90.91%.

Conclusion

This study demonstrated that visuospatial disorders was highly prevalent in PD patients, and the APP used in study could be a practical clinical screening tool for visuospatial ability assessment with high sensitivity and specificity.

Serum glial cell line-derived neurotrophic factor (GDNF) a potential biomarker of executive function in Parkinson's disease

Objective

Evidence shows that the impairment of executive function (EF) is mainly attributed to the degeneration of frontal-striatal dopamine pathway. Glial cell line-derived neurotrophic factor (GDNF), as the strongest protective neurotrophic factor for dopaminergic neurons (DANs), may play a role in EF to some extent. This study mainly explored the correlation between serum GDNF concentration and EF performance in Parkinson's disease (PD).

Methods

This study recruited 45 healthy volunteers (health control, HC) and 105 PD patients, including 44 with mild cognitive impairment (PD-MCI), 20 with dementia (PD-D), and 20 with normal cognitive function (PD-N). Neuropsychological tests were performed to evaluate EF (working memory, inhibitory control, and cognitive flexibility), attention, language, memory, and visuospatial function. All subjects were tested for serum GDNF and homovanillic acid (HVA) levels by ELISA and LC-ESI-MS/MS, respectively.

Results

PD-MCI patients showed impairments in the trail making test (TMT) A (TMT-A), TMT-B, clock drawing test (CDT) and semantic fluency test (SFT), whereas PD-D patients performed worse in most EF tests. With the deterioration of cognitive function, the concentration of serum GDNF and HVA in PD patients decreased. In the PD group, the serum GDNF and HVA levels were negatively correlated with TMT-A (r _GDNF = -0.304, P < 0.01; r _HVA = -0.334, P < 0.01) and TMT-B (r _GDNF = -0.329, P < 0.01; r _HVA = -0.323, P < 0.01) scores. Serum GDNF levels were positively correlated with auditory verbal learning test (AVLT-H) (r = 0.252, P < 0.05) and SFT (r = 0.275, P < 0.05) scores. Serum HVA levels showed a positively correlation with digit span test (DST) (r = 0.277, P < 0.01) scores. Stepwise linear regression analysis suggested that serum GDNF and HVA concentrations and UPDRS-III were the influence factors of TMT-A and TMT-B performances in PD patients.

Conclusion

The decrease of serum GDNF concentration in PD patients was associated with impaired inhibitory control, cognitive flexibility, and attention performances. The changes of GDNF and HVA might synergistically participate in the occurrence and development of executive dysfunction in PD patients.

Transcranial Magnetic Stimulation in the Treatment of Neurological Diseases

Transcranial Magnetic Stimulation (TMS) has widespread use in research and clinical application. For psychiatric applications, such as depression or OCD, repetitive TMS protocols (rTMS) are an established and globally applied treatment option. While promising, rTMS is not yet as common in treating neurological diseases, except for neurorehabilitation after (motor) stroke and neuropathic pain treatment. This may soon change. New clinical studies testing the potential of rTMS in various other neurological conditions appear at a rapid pace. This can prove challenging for both practitioners and clinical researchers. Although most of these neurological applications have not yet received the same level of scientific/empirical scrutiny as motor stroke and neuropathic pain, the results are encouraging, opening new doors for TMS in neurology. We here review the latest clinical evidence for rTMS in pioneering neurological applications including movement disorders, Alzheimer's disease/mild cognitive impairment, epilepsy, multiple sclerosis, and disorders of consciousness.

Caring for patients with cognitive dysfunction, fluctuations and dementia caused by Parkinson's disease

Cognitive dysfunction is one of the most prevalent non-motor symptoms in patients with Parkinson's disease (PD). While it tends to worsen in the later stages of disease, it can occur at any time, with 15-20% of patients exhibiting cognitive deficits at diagnosis (Aarsland et al., 2010; Goldman and Sieg, 2020). The characteristic features of cognitive dysfunction include impairment in executive function, visuospatial abilities, and attention, which vary in severity from subtle impairment to overt dementia (Martinez-Horta and Kulisevsky, 2019). To complicate matters, cognitive dysfunction is prone to fluctuate in PD patients, impacting diagnosis and the ability to assess progression and decision-making capacity. The diagnosis of cognitive impairment or dementia has a huge impact on patient independence, quality of life, life expectancy and caregiver burden (Corallo et al., 2017; Lawson et al., 2016; Leroi et al., 2012). It is therefore essential that physicians caring for patients with PD provide education, screening and treatment for this aspect of the disease. In this chapter, we provide a practical guide for the assessment and management of various degrees of cognitive dysfunction in patients with PD by approaching the disease at different stages. We address risk factors for cognitive dysfunction, prevention strategies prior to making the diagnosis, available tools for screening. Lastly, we review aspects of care, management and considerations, including decision-making capacity, that occur after the patient has been diagnosed with cognitive dysfunction or dementia.

Neuromodulation of cognition in Parkinson's disease

Neuromodulation is a widely used treatment for motor symptoms of Parkinson's disease (PD). It can be a highly effective treatment as a result of knowledge of circuit dysfunction associated with motor symptoms in PD. However, the mechanisms underlying cognitive symptoms of PD are less well-known, and the effects of neuromodulation on these symptoms are less consistent. Nonetheless, neuromodulation provides a unique opportunity to modulate motor and cognitive circuits while minimizing off-target side effects. We review the modalities of neuromodulation used in PD and the potential implications for cognitive symptoms. There have been some encouraging findings with both invasive and noninvasive modalities of neuromodulation, and there are promising advances being made in the field of therapeutic neuromodulation. Substantial work is needed to determine which modulation targets are most effective for the different types of cognitive deficits of PD.

Cognitive control in Parkinson's disease

Cognitive control is the ability to act according to plan. Problems with cognitive control are a primary symptom and a major decrement of quality of life in Parkinson's disease (PD). Individuals with PD have problems with seemingly different controlled processes (e.g., task switching, impulsivity, gait disturbance, apathetic motivation). We review how these varied processes all rely upon disease-related alteration of common neural substrates, particularly due to dopaminergic imbalance. A comprehensive understanding of the neural systems underlying cognitive control will hopefully lead to more concise and reliable explanations of distributed deficits. However, high levels of clinical heterogeneity and medication-invariant control deficiencies suggest the need for increasingly detailed elaboration of the neural systems underlying control in PD.

Current concepts in treating mild cognitive impairment in Parkinson's disease

Impairment in various aspects of cognition is recognized as an important non-motor symptom of Parkinson's disease (PD). Mild cognitive impairment in PD (PD-MCI) is common in non-demented PD patients and is often associated with severity of motor symptoms, disease duration and increasing age. Further, PD-MCI can have a significant negative effect on performance of daily life activities and may be a harbinger of development of PD dementia. Thus, there is significant interest in developing therapeutic strategies to ameliorate cognitive deficits in PD and improve cognitive functioning of PD patients. However, due to significant questions that remain regarding the pathophysiology of cognitive dysfunction in PD, remediation of cognitive dysfunction in PD has proven difficult. In this paper, we will focus on PD-MCI and will review some of the current therapeutic approaches being taken to try to improve cognitive functioning in patients with PD-MCI.

Gray matter, white matter and cerebrospinal fluid abnormalities in Parkinson's disease: A voxel-based morphometry study

BACKGROUND

Parkinson's disease (PD) is a chronic neurodegenerative disorder characterized by bradykinesia, tremor, and rigidity among other symptoms. With a 70% cumulative prevalence of dementia in PD, cognitive impairment and neuropsychiatric symptoms are frequent.

MATERIALS AND METHODS

In this study, we looked at anatomical brain differences between groups of patients and controls. A total of 138 people with PD were compared to 64 age-matched healthy people using voxel-based morphometry (VBM). VBM is a fully automated technique that allows for the identification of regional differences in gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) allowing for an objective comparison of brains of different groups of people. We used statistical parametric mapping for image processing and statistical analysis.

RESULTS

In comparison to controls, PD patients had lower GM volumes in the left middle cingulate, left lingual gyrus, right calcarine and left fusiform gyrus, also PD patients indicated lower WM volumes in the right middle cingulate, left lingual gyrus, right calcarine, and left inferior occipital gyrus. Moreover, PD patients group demonstrated higher CSF in the left caudate compared to the controls.

CONCLUSION

Physical fragility and cognitive impairments in PD may be detected more easily if anatomical abnormalities to the cingulate gyrus, occipital lobe and the level of CSF in the caudate are identified. Thus, our findings shed light on the role of the brain in PD and may aid in a better understanding of the events that occur in PD patients.

Dual monoamine oxidase B and acetylcholine esterase inhibitors for treating movement and cognition deficits in a C. elegans model of Parkinson's disease

Parkinson's disease (PD) is an age-associated neurodegenerative movement disorder that leads to loss of dopaminergic neurons and motor deficits. Approaches to neuroprotection and symptom management in PD include use of monoamine oxidase B (MAO-B) inhibitors. Many patients with PD also exhibit memory loss in the later stages of disease progression, which is treated with acetylcholine esterase (AChE) inhibitors. We sought to identify a dual-mechanism compound that would inhibit both MAO-B and AChE enzymes. Our screen identified a promising compound (7) with balanced MAO-B (IC₅₀ of 16.83 μM) and AChE inhibition activity (AChE IC₅₀ of 22.04 μM). Application of this compound 7 increased short-term associative memory and significantly prevented 6-hydroxy-dopamine toxicity in dopaminergic neurons in the Caenorhabditis elegans nematode. These findings present a platform for future development of dual-mechanism drugs to treat neurodegenerative diseases such as PD.

Polygenic Risk Scores Contribute to Personalized Medicine of Parkinson's Disease

Parkinson’s disease (PD) is the second most common neurodegenerative disorder characterized by the loss of dopaminergic neurons. The vast majority of PD patients develop the disease sporadically and it is assumed that the cause lies in polygenic and environmental components. The overall polygenic risk is the result of a large number of common low-risk variants discovered by large genome-wide association studies (GWAS). Polygenic risk scores (PRS), generated by compiling genome-wide significant variants, are a useful prognostic tool that quantifies the cumulative effect of genetic risk in a patient and in this way helps to identify high-risk patients. Although there are limitations to the construction and application of PRS, such as considerations of limited genetic underpinning of diseases explained by SNPs and generalizability of PRS to other populations, this personalized risk prediction could make a promising contribution to stratified medicine and tailored therapeutic interventions in the future.

Brain Volume and Perception of Cognitive Impairment in People With Multiple Sclerosis and Their Caregivers

Background: Cognitive impairment (CI) is common in people with multiple sclerosis (pwMS). The assessment of CI is based on neuropsychological tests and accurate anamnesis, involving the patients and caregivers (CG). This study aimed to assess the complex interplay between self-perception of CI, objective CI and the brain atrophy of MS patients, also exploring the possible differences with CI evaluated by caregivers.

Methods: Relapsing pwMS were enrolled in this study. Subjects underwent neuropsychological examination using the Brief Cognitive Assessment for Multiple Sclerosis (BICAMS) and evaluation of self-reported cognitive status using the patient-version of the Multiple Sclerosis Neuropsychological Questionnaire (p-MSNQ). Depression and anxiety were also evaluated using the Back Depression Inventory-version II (BDI-II) and Zung Anxiety Scale. Brain MRI images were acquired and brain volumes estimated. For each patient that was enrolled, we spoke to a caregiver and collected their perception of the patient's CI using the MSNQ- Caregiver version.

Results: Ninety-five MS subjects with their caregivers were enrolled. CI was detected in 51 (53.7%) patients. We found a significant correlation (p < 0.001) between BICAMS T scores and lower whole brain (Rho = 0.51), gray matter (Rho = 0.54), cortical gray matter (Rho = 0.51) volumes and lower p-MSNQ (Rho = 0.31), and cg-MSNQ (Rho = 0.41) scores. Multivariate logistic regression showed that p-MSNQ is related to a patient's anxiety to evaluate by Zung Score (p < 0.001) while cg-MSNQ to patient's brain volume (p = 0.01).

Conclusion: Our data confirm that neuropsychological evaluation results are related to the perception of CI and brain volume measures and highlight the importance of the caregiver's perception for cognitive assessment of pwMS.