Parkinson's Disease Dementia Research Articles

The protective role of basal metabolic rate in cognitive decline: evidence from epidemiological and genetic studies.

This study aims to explore the relationship between basal metabolic rate (BMR) and cognitive impairment and assess the potential of BMR as a protective factor against cognitive decline. This investigation initially conducted a cross-sectional study of American adults from 2011 to 2014 using data from the National Health and Nutrition Examination Survey. It examined the correlation between participants' BMR and cognitive functions, exploring the association with cognitive impairment. Subsequently, publicly available genome-wide association study data was used to examine potential causal links between genetically determined BMR and specific cognitive disorders using Mendelian randomization. Cross-sectional findings revealed a significant positive correlation between higher BMR and cognitive scores. In Mendelian randomization analysis, BMR demonstrated an inverse causal relationship with Alzheimer's disease and Parkinson's dementia, suggesting BMR as a potential protective factor against these diseases. No causal links were found with vascular dementia, Lewy body dementia, and frontotemporal dementia. This study supports the role of BMR as a potential protective factor against Alzheimer's disease and Parkinson's dementia, suggesting that BMR may play an important role in preventing cognitive decline. However, due to the limitations of cross-sectional studies, further prospective studies and broader demographic samples are necessary to verify these results and explore underlying biological mechanisms. Key messages What is already known on this topic: Existing knowledge suggests a close relationship between BMR and health and cognitive functions, but detailed studies on its connection with specific cognitive impairments are still needed. What this study adds: This study found a significant positive correlation between higher BMR and cognitive improvement, potentially aiding in the prevention of Alzheimer's and Parkinson's dementia. How this study might affect research, practice, or policy: This finding guides public health strategies and personalized medicine, emphasizing the necessity for further research to validate BMR's protective effects.

Electrochemical biosensors for dopamine.

Dopamine (DA), a key catecholamine, plays a pivotal role in the regulation of human cognition and emotions. It has profound effects on the hormonal, memory, and cardiovascular systems. Anomalies like Alzheimer's, Parkinson's, schizophrenia, and senile dementia are linked to abnormal DA levels. Consequently, the precise determination of DA levels in biological systems is critical for the accurate diagnosis and treatment of these disorders. Among all analytical techniques, electrochemical studies provide the most selective and highly sensitive methods for detecting DA in biological samples. Ascorbic acid and uric acid are two examples of small biomolecules that can obstruct the detection of DA in biological fluids. To address this issue, numerous attempts have been made to modify bare electrodes to separate the signals of these substances and enhance the electrocatalytic activity towards DA. Various surface modifiers, including coatings, conducting polymers, ionic liquids, nanomaterials, and inorganic complexes, have been employed in the modification process. Despite the reported success in DA detection using electrochemical sensors, many of these approaches are deemed too complex and costly for real-world applications. Therefore, this review aims to provide an overview of DA electrochemical biosensors that are practical for real-world applications.

Patterns of tau, amyloid and synuclein pathology in ageing, Alzheimer's disease and synucleinopathies.

Alzheimer's disease (AD) is neuropathologically defined by deposits of misfolded hyperphosphorylated tau (HP-tau) and β-amyloid. Lewy body (LB) dementia, which includes dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD), is characterised pathologically by α-synuclein aggregates. HP-tau and β-amyloid can also occur as copathologies in LB dementia, and a diagnosis mixedAD/DLB can be made if present in sufficient quantities. We hypothesised the spread of these abnormal proteins selectively affects vulnerable areas, resulting in pathologic regional covariance that differentially associates with pre-mortem clinical characteristics. Our aims were to map regional quantitative pathology (HP-tau, β-amyloid, α-synuclein) and investigate the spatial distributions from tissue microarray (TMA) post-mortem samples across healthy aging, AD and LB dementia. The study involved 159 clinico-pathologically diagnosed human post-mortem brains (48 controls, 47 AD, 25 DLB, 20 mixedAD/DLB, 19 PDD). The burden of HP-tau, β-amyloid and α-synuclein was quantitatively assessed in cortical and subcortical areas. Principal components (PC) analysis was applied across all cases to determine the pattern nature of HP-tau, β-amyloid and α-synuclein. Further analyses explored the relationships of these pathological patterns with cognitive and symptom variables. Cortical (tauPC1) and temporolimbic (tauPC2) patterns were observed for HP-tau. For β-amyloid, a cortical-subcortical pattern (amylPC1) was identified. For α-synuclein, four patterns emerged: 'posterior temporal - occipital (synPC1)', 'anterior temporal-frontal (synPC2)', 'parieto-cingulate-insula (synPC3)', and 'frontostriatal-amygdala (synPC4)'. Distinct synPC scores were apparent among DLB, mixedAD/DLB and PDD, and may relate to different spreading patterns of α-synuclein pathology. In dementia, cognitive measures correlated with tauPC1, tauPC2 and amylPC1 pattern scores (P≤0.02), whereas such variables did not relate to α-synuclein parameters in these or combined LB dementia cases. Mediation analysis then revealed that in the presence of amylPC1, tauPC1 had a direct effect on global cognition in dementia (n=65, P=0.04), while tauPC1 mediated the relationship between amylPC1 and cognition through the indirect pathway (amylPC1→ tauPC1 → global cognition) (P<0.05). Lastly, in synucleinopathies, synPC1 and synPC4 pattern scores were associated with visual hallucinations and motor impairment, respectively (P=0.02). In conclusion, distinct patterns of α-synuclein pathology were apparent in LB dementia, which could explain some of the disease heterogeneity and differing spreading patterns among these conditions. Visual hallucinations and motor severity were associated with specific α-synuclein topographies in LB dementia that may be important to the clinical phenotype, and could, after necessary testing/validation, be integrated into semi-quantitative routine pathological assessment.

Glucocerebrosidase deficiency leads to neuropathology via cellular immune activation.

Mutations in GBA (glucosylceramidase beta), which encodes the lysosomal enzyme glucocerebrosidase (GCase), are the strongest genetic risk factor for the neurodegenerative disorders Parkinson's disease (PD) and Lewy body dementia. Recent work has suggested that neuroinflammation may be an important factor in the risk conferred by GBA mutations. We therefore systematically tested the contributions of immune-related genes to neuropathology in a Drosophila model of GCase deficiency. We identified target immune factors via RNA-Seq and proteomics on heads from GCase-deficient flies, which revealed both increased abundance of humoral factors and increased macrophage activation. We then manipulated the identified immune factors and measured their effect on head protein aggregates, a hallmark of neurodegenerative disease. Genetic ablation of humoral (secreted) immune factors did not suppress the development of protein aggregation. By contrast, re-expressing Gba1b in activated macrophages suppressed head protein aggregation in Gba1b mutants and rescued their lifespan and behavioral deficits. Moreover, reducing the GCase substrate glucosylceramide in activated macrophages also ameliorated Gba1b mutant phenotypes. Taken together, our findings show that glucosylceramide accumulation due to GCase deficiency leads to macrophage activation, which in turn promotes the development of neuropathology.

REM sleep behavior disorder: Relation between aggressiveness and emotions expressed in dream enactment and cognitive and anxiety/depression status

Aggressiveness and negative emotions in dreams reports of patients with alfa-synucleinopathies have been associated with cognitive dysfunction. Observation of dream enactment episodes could be a more precise method to capture dream content in patients with REM sleep behavior disorder (RBD). Our objective was to assess the relation between aggressive and emotional dream enactment episodes in patients with RBD and cognition and depression/anxiety.Motor events (ME) during REM sleep were classified by visual inspection of video-PSG files. Cognition and anxiety/depression were assessed with MoCA and the Hospital Anxiety and Depression Scale (HADS), respectively. Multivariate regression analysis was performed, with MoCA or HADS scores as predictors, age and DED as co-variates and aggressive, negative and positive ME frequency (raw values, per total and per complex indexes) as the dependent variable.We included 15 patients with isolated RBD and 12 and 4 with RBD associated with Parkinson's disease and Dementia with Lewy Bodies, respectively. They presented a total of 873 ME. There was a significant positive association between HADS score and violent/complex and negative emotion/complex indexes. There was a significant positive association between MoCA score and violent/complex index.A significant correlation between depression/anxiety severity and negative emotion and aggression ME frequency agrees with the dream continuity hypothesis and suggests that REM sleep acts as a regulator of emotional experience. Patients with a higher prevalence of aggressive ME had higher scores in cognitive testing, suggesting that the elaboration of these complex movements could depend on the integrity of cognitive functions.

Motor signs and incident dementia with Lewy bodies in older adults with mild cognitive impairment.

Motor signs may herald incident dementia and allow the earlier detection of high-risk individuals and the timely implementation of preventive interventions. The current study was performed to investigate the prognostic properties of motor signs with respect to incident dementia with Lewy bodies (DLB) in older adults with mild cognitive impairment (MCI). Emphasis was placed on sex differences. The specificity of these associations was explored. We analyzed data from the National Alzheimer's Coordinating Center Uniform Data Set. Participants 55 + years old with a diagnosis of MCI were included in the analysis. Those with Parkinson's disease (PD) or other parkinsonian disorders at baseline and those with PD dementia at follow-up were excluded. UPDRS III was used to assess the presence or absence of motor signs in nine domains: hypophonia; masked facies; resting tremor; action/postural tremor; rigidity; bradykinesia; impaired chair rise; impaired posture/gait; postural instability. Αdjusted Cox proportional hazards models featuring sex by motor sign interactions were estimated. Throughout the average follow-up of 3.7 ± 3.1 years, among 4623 individuals with MCI, 2211 progressed to dementia (66 of whom converted to DLB). Masked facies [HR = 4.21 (1.74-10.18)], resting tremor [HR = 4.71 (1.44-15.40)], and bradykinesia [HR = 3.43 (1.82-6.45)] exclusively increased the risk of DLB. The HR of DLB was approximately 15 times greater in women compared to men with masked facies. Impaired posture-gait (approximately 10 times) and resting tremor (approximately 8.5 times) exhibited a similar trend (prominent risk-conferring properties in women compared to men) but failed to achieve statistical significance. Rigidity and hypophonia elevated the risk of other dementia entities, as well. The remaining motor features were not related to incident dementia of any type. Specific motor signs may herald DLB among individuals with MCI. Different associations may exist between masked facies, impaired posture-gait, resting tremor, and incident DLB in men versus women.

A novel clinical prediction model for hip fractures: a development and validation study in the total population of Sweden

Low bone density and osteoporosis are indications for bone-specific treatment. However, given the limited availability of bone density data in clinical practice and the fact that most patients with hip fracture do not have osteoporosis, accurate prediction of hip fracture risk in the absence of bone density data would be crucial. This development and validation study included the entire Swedish population aged 50 years or older in 2005 (N=3,340,977) and was conducted by cross-linking data from nationwide registers. Potential predictive variables included diagnoses, prescription medications, familial factors, frailty-related factors, and socioeconomic factors. The primary endpoint was the 5-year risk of hip fracture. Fracture prediction algorithms were developed and validated using multivariable models. Model performance and validation was also examined in a sub cohort restricted to 504,431 individuals with non-Swedish background. During a total follow-up of 15.2 million person-years, 87,089 individuals suffered a hip fracture within 5 years. In the final prediction model, 19 variables were associated with a population attributable fraction of 93.9% (95% CI, 93.7-94.1) in women and 92.7% (95% CI, 92.2-93.0) in men. The strongest predictor, besides old age, was the use of homemaker service, with a 5-year risk of hip fracture of 7.8% in women and 4.7% in men. The diagnoses most strongly predicting the 5-year risk of hip fracture was Parkinson's disease (6.8% in women, 4.6% in men) and dementia (6.1% in women, 3.6% in men). Validation of the prediction model suggested that the optimal threshold for treatment with bone-specific agents was an estimated 5-year hip fracture risk of 3%. Assuming a threshold of 3% and a 30% relative risk reduction from bone-specific treatment, the number needed to treat to prevent one hip fracture was estimated to 36 in women and 52 in men. Similar results were obtained in the sub cohort with non-Swedish background. A clinical prediction model developed and validated in the total Swedish population could predict the risk of hip fractures with high precision even in absence of data on bone density. The model was associated with a population attributable fraction for hip fracture of more than 90%, and the strongest predictor besides old age was the use of homemaker service, which likely reflect frailty. Based on the model, individuals with an estimated 5-year risk of hip fracture of at least 3% could be considered for bone-specific treatment. None.

Workup of Parkinson's Disease, Parkinson Plus, Lewy Body, and Alzheimer's Dementia Should Include SPECT, PET and Genetics.

Workup of Parkinson's Disease, Parkinson Plus, Lewy Body, and Alzheimer's Dementia Should Include SPECT, PET and Genetics.

Measurement of α-synuclein as protein cargo in plasma extracellular vesicles

Extracellular vesicles (EVs) are released by all cells and hold great promise as a class of biomarkers. This promise has led to increased interest in measuring EV proteins from both total EVs as well as brain-derived EVs in plasma. However, measuring cargo proteins in EVs has been challenging because EVs are present at low levels, and EV isolation methods are imperfect at separating EVs from free proteins. Thus, knowing whether a protein measured after EV isolation is truly inside EVs is difficult. In this study, we developed methods to measure whether a protein is inside EVs and quantify the ratio of a protein in EVs relative to total plasma. To achieve this, we combined a high-yield size-exclusion chromatography protocol with an optimized protease protection assay and Single Molecule Array (Simoa) digital enzyme-linked immunoassays (ELISAs) for ultrasensitive measurement of proteins inside EVs. We applied these methods to analyze α-synuclein and confirmed that a small fraction of the total plasma α-synuclein is inside EVs. Additionally, we developed a highly sensitive Simoa assay for phosphorylated α-synuclein (phosphorylated at the Ser129 residue). We found enrichment in the phosphorylated α-synuclein to total α-synuclein ratio inside EVs relative to outside EVs. Finally, we applied the methods we developed to measure total and phosphorylated α-synuclein inside EVs from Parkinson's disease and Lewy body dementia patient samples. This work provides a framework for determining the levels of proteins in EVs and represents an important step in the development of EV diagnostics for diseases of the brain, as well as other organs.

Increased dementia risk in patients with Parkinson's disease attributed to metabolic syndrome.

Metabolic syndrome (MetS) manifests resembling pathophysiological mechanisms with Parkinson's disease (PD). Current research on the overall population has emphasized MetS as a freestanding risk factor for cognition. This research aims to explore the impact of MetS on cognition in Parkinson's patients. We involved subjects identified as having early-stage PD patients. The MetS was diagnosed dependent on parameters overviewed in the National Cholesterol Education Program's Adult Treatment Panel III. The clinical severity and stages in patients with PD were dependent on the disease rating scales. The cognition was evaluated by the Turkısh version of the Montreal Cognitive Assessment Scale (MoCA-TR). The cases were categorized according to cognitive failure: mild cognitive impairment in PD (PD-MCI), and PD dementia (PDD). Metabolic syndrome was present in 39.6% of the participants. 22.0% of patients were in the normal cognition, 29.1% in the PD-MCI group, and 48.9% in the PD-D group. The cognitive scores in patients with MetS is considerably lower than MetS negative group. A statistically notable inverse association was detected between fasting blood glucose levels and the visual-spatial/executive functions, naming, language, and orientation scores. The multivariate logistic regression analysis showed individuals with MetS were found to have an 11.308 times higher risk of PD-D (odds ratio [OR]: 11,3, 95% confidence interval [CI]: 1.61-79.2 ). We discerned the occurrence of MetS in PD raises the possibility of advancing dementia. This suggests that considering MetS in this patient group could contribute to the effective management of dementia.

Biomarker Assessment in Parkinson's Disease Dementia and Dementia with Lewy Bodies by the Immunomagnetic Reduction Assay and Clinical Measures.

Plasma biomarker assays provide an opportunity to reassess whether Alzheimer's disease, Parkinson's disease dementia (PDD), and dementia with Lewy bodies (DLB) plasma biomarkers are diagnostically useful. We hypothesized that immunomagnetic reduction (IMR) of plasma biomarkers could differentiate between patients with PDD and DLB and healthy patients when combined with established clinical testing measures. Plasma samples from 61 participants (12 PDD, 12 DLB, 37 controls) were analyzed using IMR to quantify amyloid-β 42 (Aβ42), total tau (t-tau), phosphorylated tau at threonine 181 (p-tau181), and α-synuclein (α-syn). Receiver operating characteristic curve (ROC) analysis was used to obtain sensitivity, specificity, and area under the ROC curve. Biomarker results were combined with clinical measures from the Unified Parkinson's Disease Rating Scale (UPDRS), Montreal Cognitive Assessment, and Hoehn-Yahr stage to optimize diagnostic test performance. Participants with PDD had higher α-syn than those with DLB and healthy participants and were distinguishable by their biomarker products Aβ42×p-tau181 and Aβ42×α-syn. Patients with DLB had higher p-tau181 than those with PDD and healthy participants and were distinguishable by their concentrations of α-syn×p-tau181. Plasma α-syn plus UPDRS versus either test alone increased sensitivity, specificity, and AUC when healthy patients were compared with those with PDD and DLB. Combined clinical examination scores and plasma biomarker products demonstrated utility in differentiating PDD from DLB when p-tau181 was combined with UPDRS, α-syn was combined with UPDRS, and α-syn×p-tau181 was combined with UPDRS. In this pilot study, IMR plasma p-tau181 and α-syn may discriminate between PDD and DLB when used in conjunction with clinical testing.

Mitochondrial Dysfunction in Parkinson's Disease: A Contribution to Cognitive Impairment?

Among the non-motor symptoms associated with Parkinson's disease (PD), cognitive impairment is one of the most common and disabling. It can occur either early or late during the disease, and it is heterogeneous in terms of its clinical manifestations, such as Subjective Cognitive Dysfunction (SCD), Mild Cognitive Impairment (MCI), and Parkinson's Disease Dementia (PDD). The aim of the present review is to delve deeper into the molecular mechanisms underlying cognitive decline in PD. This is extremely important to delineate the guidelines for the differential diagnosis and prognosis of the dysfunction, to identify the molecular and neuronal mechanisms involved, and to plan therapeutic strategies that can halt cognitive impairment progression. Specifically, the present review will discuss the pathogenetic mechanisms involved in the progression of cognitive impairment in PD, with attention to mitochondria and their contribution to synaptic dysfunction and neuronal deterioration in the brain regions responsible for non-motor manifestations of the disease.

CSF d18:1 sphingolipid species in Parkinson disease and dementia with Lewy bodies with and without GBA1 variants

Variants in GBA1 result in dysregulated sphingolipids. We investigated five CSF d18:1 sphingolipid species in a longitudinal multicenter cohort comprising people with Parkinson’s Disease and Dementia with Lewy bodies with and without GBA1 variants and healthy controls. We found no increase of sphingolipid species in heterozygous GBA1 variant participants and no effect on development of cognitive impairment. Thus, CSF d18:1 sphingolipids are not suitable as state markers in Parkinson’s Disease.

Insular monoaminergic deficits in prodromal α-synucleinopathies.

This study assessed data from two cohorts of patients with alpha-synucleinopathies (University of Brescia and University of Rome Tor-Vergata cohorts). Consecutive participants with video-polysomnography-confirmed iRBD, Parkinson's disease (PD), dementia with Lewy bodies (DLB) and controls underwent neurological, clinical and 123I-FP-CIT SPECT imaging assessments. Individuals with iRBD were longitudinally monitored to collect clinical phenoconversion to PD or DLB. The main outcome was to identify whole brain 123 I-FP-CIT SPECT measures reflecting monoaminergic deficits in each clinical group as compared to controls. The cohort (n = 184) included 45 patients with iRBD, 47 PD, 42 DLB and 50 age-matched controls. Individuals with iRBD were categorized as RBD-DAT- (n = 32) and RBD-DAT+ (n = 13), according to nigrostriatal assessment used in clinical practice. Compared to controls, RBD-DAT- showed an early involvement of the left insula, which increased in RBD-DAT+, and was present in patients with Parkinson's disease and dementia with Lewy bodies. Longitudinal cox regression analyses revealed a higher risk of phenoconversion in individuals with iRBD and insular monoaminergic deficits [HR = 3.387; CI 95%: 1.18-10.27]. In this study, altered insular monoaminergic binding in iRBD was associated with phenoconversion to DLB or PD. These findings may provide a helpful stratification approach for future pharmacological or non-pharmacological interventions.

Therapeutic potential of phytocompounds of Bacopa monnieri (L.) Wettst (literature review)

The aim of the work was to evaluate the pharmacological effects and therapeutic potential of individual compounds and extracts of B. monnieri based on the analysis of data from scientific periodicals regarding chemical composition and biological action. Theoretically significant were the studies of the materials of the scientific-metric database PubMed and Google Scholar over the last five years regarding the chemical composition and biological action of extracts based on B. monnieri and their individual components. The search query was carried out by the Latin name of the plant, with the exception of publications related to botanical research. In separate PubChem searches, names of individual phytocompounds were used to establish structure and distribution in plants. The SuperPred web server was used to predict therapeutic potential. The authors analyzed the chemical composition of the extracts, presented the structural and pharmacological characteristics of bacosides and their aglycones: bacosin and juubogenin, cucurbitacin E, loliolide, betulinic and asiatic acids and the flavonoid oroxindin. The mechanism of action of bacoside on β-amyloid is characterized and illustrated. Using machine learning, the prospects for using the main compounds of bacopa to create drugs were calculated taking into account the ATC classification, their biological effects and alternative plant sources were given. Experimental animal studies of whole aqueous or ethanolic extracts of B. monnieri have been found to support a cognitive enhancement effect. The extract was not toxic to humans. Numerous clinical trials show the effectiveness of the use of extracts in the treatment of anhedonia, depression, Alzheimer's disease, Parkinson's disease, dementia and hyperactivity. An analysis of clinical studies in Ukraine shows that drugs based on B. monnieri can be used in the complex treatment of cognitive impairment associated with dyscirculatory encephalopathy in adults and perinatal CNS damage in children. Considering the amphiphilicity of bacosides and the non-toxicity of extracts, they can be involved in the development of various dosage forms with a wide range of therapeutic applications. Further study of the pharmacological action of B. monnieri and the development of drug technology for solid and liquid dosage forms based on it are promising.

Sex Differences in Neuropsychiatric Symptoms in Alpha-Synucleinopathies: A Systematic Review and Meta-Analysis.

Alpha-synucleinopathies, such as Parkinson's disease (PD), Parkinson's disease dementia (PDD), and dementia with Lewy bodies (DLB), demonstrate sex differences with regard to prevalence, age of onset, and motor manifestations. Neuropsychiatric symptoms (NPS) are common early and late manifestations of these disorders. We aimed to describe sex differences in NPS across alpha-synucleinopathies. We searched Web of Science Core collection databases to identify observational studies published between January 1, 2000, and June 1, 2022, reporting the prevalence or severity of NPS among individuals with a diagnosis of PD, PDD, or DLB. Prevalence and severity were pooled for each NPS according to sex using random-effects models. Two-hundred-and-forty studies, representing 796,026 participants (45% females), were included in the meta-analysis. Female sex was associated with a higher prevalence of anxiety (OR = 1.60 [95% CI: 1.40, 1.82]), depression (OR = 1.56 [1.45, 1.67]), fatigue (OR = 1.21 [1.02, 1.43]), and psychotic symptoms (OR = 1.26 [1.14, 1.40]) and more severe anxiety (g = 1.35 [95% CI: 0.58, 2.13]), depression (g = 1.57 [1.05, 2.08]), and fatigue (g = 0.86 [0.41, 1.32]), while male sex was associated with a higher prevalence of apathy (OR = 0.77 [0.63, 0.93]), impulse control disorders (OR = 0.67 [0.55, 0.82]), REM sleep behavior disorder (OR = 0.54 [0.42, 0.70]), hypersomnolence (OR = 0.67 [0.56, 0.80]), and suicide (OR = 0.30 [0.20, 0.44]). NPS have different prevalences and severities in alpha-synucleinopathies according to sex. These findings support consideration of sex in the elaboration of clinical tools.

Examining Agreement in Psychotic Symptom Assessment: Insights from Parkinson's Disease Dementia Dyads.

Psychosis and cognitive decline often co-occur in Parkinson's Disease (PD), which complicates assessment. We measured agreement between patients with PD and dementia (PDD) and care partners (CPs) in their independent evaluation of PD-related psychotic symptoms. We compared responses to a PD psychosis rating scale (SAPS-PD) in 21 dyads of patients with PDD and cognitively normal CPs. We assessed the concordance of responses using the intraclass correlation coefficient (ICC). Following the psychosis assessment, the clinician used all available information and adjudicated who provided the most reliable responses. Dyads demonstrated poor concordance in summary scores (ICC = 0.464). Six of the nine individual items had poor agreement. The clinician adjudicated the patient's response as the more reliable in 71.4% of cases. Although many psychotic symptoms are internal and not observable, in the context of PDD, both patient and CP inputs are valuable, but final adjudication favors patient responses.

Cholinergic Basal Forebrain Integrity and Cognition in Parkinson's Disease: A Reappraisal of Magnetic Resonance Imaging Evidence.

Cognitive impairment is a well-recognized and debilitating symptom of Parkinson's disease (PD). Degradation in the cortical cholinergic system is thought to be a key contributor. Both postmortem and in vivo cholinergic positron emission tomography (PET) studies have provided valuable evidence of cholinergic system changes in PD, which are pronounced in PD dementia (PDD). A growing body of literature has employed magnetic resonance imaging (MRI), a noninvasive, more cost-effective alternative to PET, to examine cholinergic system structural changes in PD. This review provides a comprehensive discussion of the methodologies and findings of studies that have focused on the relationship between cholinergic basal forebrain (cBF) integrity, based on T1- and diffusion-weighted MRI, and cognitive function in PD. Nucleus basalis of Meynert (Ch4) volume has been consistently reduced in cognitively impaired PD samples and has shown potential utility as a prognostic indicator for future cognitive decline. However, the extent of structural changes in Ch4, especially in early stages of cognitive decline in PD, remains unclear. In addition, evidence for structural change in anterior cBF regions in PD has not been well established. This review underscores the importance of continued cross-sectional and longitudinal research to elucidate the role of cholinergic dysfunction in the cognitive manifestations of PD. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Cholinergic dysfunction in isolated rapid eye movement sleep behaviour disorder links to impending phenoconversion.

Most patients with isolated rapid eye movement sleep behaviour disorder (iRBD) progress to a parkinsonian alpha-synucleinopathy. However, time to phenoconversion shows great variation. The aim of this study was to investigate whether cholinergic and dopaminergic dysfunction in iRBD patients was associated with impending phenoconversion. Twenty-one polysomnography-confirmed iRBD patients underwent baseline 11C-donepezil and 6-Fluoro-(18F)-l-3,4-dihydroxyphenylalanine (18F-DOPA) positron emission tomography (PET). Potential phenoconversion was monitored for up to 8 years. PET images were analysed according to patients' diagnoses after 3 and 8 years using linear regression. Time-to-event analysis was made with Cox regression, dividing patients into low and high tracer uptake groups. Follow-up was accomplished in 17 patients. Eight patients progressed to either Parkinson's disease (n = 4) or dementia with Lewy bodies (n = 4), while nine remained non-phenoconverters. Compared with non-phenoconverters, 8-year phenoconverters had lower mean 11C-donepezil uptake in the parietal (p = 0.032) and frontal cortex (p = 0.042), whereas mean 11C-donepezil uptake in 3-year phenoconverters was lower in the parietal cortex (p = 0.005), frontal cortex (p = 0.025), thalamus (p = 0.043) and putamen (p = 0.049). Phenoconverters within 3 years and 8 years had lower 18F-DOPA uptake in the putamen (p < 0.001). iRBD patients with low parietal 11C-donepezil uptake had a 13.46 (95% confidence interval 1.42;127.21) times higher rate of phenoconversion compared with those with higher uptake (p = 0.023). iRBD patients with low 18F-DOPA uptake in the most affected putamen were all phenoconverters with higher rate of phenoconversion (p = 0.0002). These findings suggest that cortical cholinergic dysfunction, particularly within the parietal cortex, could be a biomarker candidate for predicting short-term phenoconversion in iRBD patients. This study aligns with previous reports suggesting dopaminergic dysfunction is associated with forthcoming phenoconversion.

Genetic variability of incretin receptors affects the occurrence of neurodegenerative diseases and their characteristics

BackgroundAlzheimer's disease (AD) and Parkinson's disease (PD) are the most common neurodegenerative diseases. Their treatment options are rather limited, and no neuroprotective or disease-modifying treatments are available. Anti-diabetic drugs, such as glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) agonists, have been suggested as a potential therapeutic option. AimsAssess GLP1R and GIPR genetic variability in relation to AD- and PD-related phenotypes. MethodsAD, PD patients and healthy control subjects were included in the study. Cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease were measured in AD patients, while cognitive impairment was evaluated in PD. All participants were genotyped for three SNPs: GLP1R rs10305420, GLP1R rs6923761 and GIPR rs1800437. ResultsGLP1R rs10305420 genotypes were associated with increased odds for AD and PD development. GLP1R rs10305420 and GLP1R rs6923761 genotypes were significantly associated with Aβ42/40 ratio (p = 0.041 and p = 0.050), while GLP1R rs6923761 was also associated with p-tau levels (p = 0.022). Finally, GIPR rs1800437 heterozygotes as well as carriers of at least one GIPR rs1800437 C allele presented with increased odds for the development of dementia in PD (OR = 1.92; 95 % CI = 1.05–3.51; p = 0.034 and OR = 1.95; 95 % CI = 1.08–3.52; p = 0.027, respectively). ConclusionGLP1R and GIPR genetic variability may affect the occurrence of AD and PD and is also associated with AD CSF biomarkers for Alzheimer's disease and dementia in PD. The data on GLP1R and GIPR genetic variability may support the function of incretin receptors in neurodegeneration.