A systematic review and meta-analysis on the association between orthostatic hypotension and mild cognitive impairment and dementia in Parkinson's disease

Nighttime systolic blood pressure reduction rate and periventricular white matter hyperintensity were associated with cognitive function in Parkinson's disease

INTRODUCTION

This study aimed to investigate the relationship between nighttime systolic blood pressure (NSBP) reduction rate, white matter hyperintensity (WMH), and cognitive function in Parkinson's disease (PD) patients.

METHODS

All PD participants underwent 24-hour ambulatory blood pressure monitor and MRI, with the volumes of WMHs quantified. Participants were categorized into normal dipping and non-dipping groups based on dipping patterns, as well as dementia and non-dementia groups according to a Montreal Cognitive Assessment (MoCA) score of less than 20. Multivariate linear regression analysis was performed to identify independent risk factors for cognitive function.

RESULTS

Compared to normal dippers (n = 13), non-dippers (n = 39) showed significantly lower MoCA scores, higher volumes of periventricular WMH, ratios of periventricular WMH to white matter (WM), and ratios of deep WMH to WM (P = 0.027; 0.015; 0.011; 0.023). Moreover, the ratios of juxtaventricular WMH to WM, periventricular WMH to WM, and deep WMH to WM in the dementia group were significantly higher than those in the non-dementia group (P = 0.003; 0.001; 0.011). Regression analysis revealed that education and NSBP reduction rate were independent protective factors (OR = 4.107, P < 0.001; OR = 2.062, P = 0.045), whereas ratio of periventricular WMH to WM was an independent risk factor (OR= -2.640; P = 0.011) for cognitive function in PD patients.

CONCLUSIONS

NSBP reduction rate and ratio of periventricular WMH to periventricular WM were associated with cognitive function in PD patients. Reduced NSBP reduction may contribute to the development of WMH and consequent cognitive impairment in PD patients.

Non-motor Symptoms and Treatments in Parkinson's Disease

SYNOPSIS

Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor and non-motor symptoms. The non-motor features may precede the onset of motor symptoms and occur throughout all stages of PD. The non-motor symptoms reflect multisystem involvement of the central and peripheral nervous systems, multiple neurotransmitters, and multiple pathologies. PD management necessitates a comprehensive approach to address non-motor symptoms, including pharmacologic and non-pharmacological interventions and often multiple different disciplines or specialists in the PD care team. This review article discusses symptoms and treatments for the non-motor symptoms of PD including those affecting mood, cognition, behavior, sleep, autonomic function, and sensory systems.

Orthostatic hypotension is involved in cognitive impairment in patients with multiple system atrophy: a multi-center cohort study in China

BACKGROUND

Orthostatic hypotension (OH) is a common symptom of multiple system atrophy (MSA), however, its role in cognitive impairment and the mechanism in these patients remains unclear. This study aims to assess the role of OH on cognitive impairment in MSA patients, as well as to explore the potential association of cerebral autoregulation (CA) and white matter hyperintensities (WMHs) on cognitive impairment.

METHODS

This observational study was conducted in three general hospitals in China from January 2018 to October 2023, with patients at one center followed up for 6 months after enrollment. The primary outcomes included cognitive function assessed using the Mini-Mental State Examination (MMSE) and Montreal cognitive assessment (MoCA). Secondary outcomes included the results of the Head-up tilt test, scores for CA and the extent of WMHs.

RESULTS

The 132 MSA patients included 72 men (54.54%) with a mean age of 61.16 (7.80) years. Among them, 80 patients (60.61%) had orthostatic hypotension, and 48 patients (36.36%) had cognitive impairment. OH plays an important role in cognitive impairment in MSA patients (OR = 0.328,95% CI 0.135-0.797, P = 0.014). Cognitive impairment was associated with impaired CA (OR = 0.088,95% CI 0.012-0.657, P = 0.018) and severe WMHs (OR = 0.030,95% CI 0.002-0.423, P = 0.009), particularly in the presence of OH.

CONCLUSION

OH is associated with cognitive impairment in MSA patients, and cognitive decline is linked to impaired CA and increased WMHs. Future studies are needed to explore the mechanisms underlying cognitive impairment in MSA patients.

Neurogenic Orthostatic Hypotension in Parkinson Disease-A Narrative Review of Diagnosis and Management

Background: Neurogenic orthostatic hypotension (NOH) is a significant non-motor manifestation of Parkinson's disease (PD), that substantially affects patient disability and has a powerful impact on the quality of life of PD patients, while also contributing to increased healthcare costs. This narrative review aims to summarize key insights into the diagnosis and management of NOH in individuals with PD. Methods: For diagnosing NOH, a recently introduced and valuable metric is the ΔHr/ΔSBP index. Additional tools, such as autonomic reflex testing and various blood tests, also can be used to help distinguish orthostatic hypotension (OH) from NOH. Results: Treatment strategies for NOH involve both non-pharmacological and pharmacological approaches. As NOH frequently coexists with other abnormal blood pressure patterns (supine hypertension, nocturnal hypertension, and non-dipping hypertension), its treatment can be a challenge for the clinician. Droxidopa and midodrine are the primary pharmacological agents for NOH, though emerging therapies, such as norepinephrine transporter inhibitors, are being investigated. Conclusions: Despite these advancements, further research is needed to better understand the underlying pathophysiology of NOH, enabling more tailored and effective treatment options for individuals with PD.

Transcranial direct current stimulation and cognitive changes in Parkinson's disease, a systematic review with meta-analysis and meta-regression

Parkinson's disease is the second most common neurodegenerative disease, but therapeutic options such as neuromodulation continue to show variable effects, making clinical management of the disease difficult. This systematic review with meta-analysis and meta-regression aimed to analyze the isolated effect of cortical modulation with transcranial direct current stimulation (tDCS) compared to sham stimulation on cognitive changes in people with Parkinson's disease. The databases used were: Web of Science, Scopus, PsycINFO, PubMed, and Cochrane. The results showed that tDCS can influence the improvement of cognition in PD (Inverse Variance:0.24 [95% Confidence Interval: 0.09 to -0.40], p < 0.00). The meta-analysis showed that active tDCS can influence cognitive function by improving aspects related to memory (Inverse Variance:0.34 [95% Confidence Interval: 0.07 to 0.61], p < 0.01) and reducing reaction time in cognitive tasks (Inverse Variance:0.42 [95% Confidence Interval: 0.07 to 0.76], p < 0.02). Innovative meta-regression analyses showed that variables such as age (Q = 2.54, df = 1, p < 0.11), education level (Q = 2.62, df = 1, p < 0.10), disease duration (Q = 0.01, df = 1, p < 0.92), and Unified PD Rating Scale stage (Q = 0.01, df = 1, p < 0.92) did not influence the results. Thus, tDCS may be a therapeutic option for cognitive changes in people with PD, and we suggest further studies to identify protocols that can be replicated.

Longitudinal prevalence of neurogenic orthostatic hypotension in the idiopathic Parkinson Progression Marker Initiative (PPMI) cohort

BACKGROUND

Reported orthostatic hypotension (OH) prevalence in Parkinson's disease (PD) varies widely, with few studies evaluating specifically neurogenic-OH (nOH). The ratio of orthostatic heart rate (HR) to systolic blood pressure (SBP) change (Δ) is a valid screening method to stratify nOH/non-nOH but has had minimal epidemiologic application.

OBJECTIVE

To estimate the prevalence of nOH and non-nOH in the PPMI using the ΔHR/ΔSBP ratio and examine associations between nOH and various motor and non-motor measures.

METHODS

Longitudinal orthostatic vitals and motor and non-motor measures were extracted (baseline-month 48). Patients were consensus criteria classified as OH+/-, with ΔHR/ΔSBP sub-classification to nOH (ΔHR/ΔSBP < 0.5) or non-nOH (ratio ≥ 0.5). Prevalence was determined across visits. Independent linear mixed models tested associations between nOH/non-nOH and clinical variables.

RESULTS

Of N = 907 PD with baseline orthostatic vitals, 3.9 % and 1.8 % exhibited nOH and non-nOH, respectively. Prevalence of nOH/non-nOH increased yearly (P = 0.012, chi-square), though with modest magnitude (baseline: 5.6 % [95 % CI: 4.3-7.3 %]; month 48: 8.6 % [6.4-11.5 %]). nOH patients were older than PD with no OH and nOH was associated with greater impairment of motor and independent functioning than non-nOH/OH- groups. Cognitive function and typical OH symptoms were worse in PD + OH, generally.

CONCLUSIONS

nOH prevalence was greater than non-nOH in the PPMI early PD cohort, with modest prevalence increase over time. Our findings are consistent with prior studies of large cohorts that evaluated nOH, specifically. Those with early PD and nOH were likelier to be older and suffer from greater motor and functional impairment, but OH presence was generally associated with more cognitive impairment.

Orthostatic Hypotension and Cognitive Function in Individuals 85 Years of Age: A Longitudinal Cohort Study in Sweden

Orthostatic hypotension (OH) is more common in the elderly and associated with increased mortality. However, its implications for 85-year-olds are not known. In the prospective observational cohort study Elderly in Linköping Screening Assessment (ELSA 85), 496 individuals in Linköping, Sweden, were followed from age 85 years with cognitive assessments. Blood pressure (BP) was measured supine and after 1, 3, 5, and 10 minutes of standing. Participants with a BP fall of ≥20 mmHg systolic or ≥10 mmHg diastolic after 1 or 3 minutes were classified as classical continuous or classical transient OH depending on whether the BP fall was sustained or not, at subsequent measurements. Those with a BP fall of the same magnitude, but only after 5 or 10 minutes were classified as delayed OH. Of participants, 329 took part in BP measurements and were included. Of these, 156 (47.4%) had classical OH (113 [34.3%] continuous classical, 38 [11.6%] transient classical), and 15 (4.6%) had delayed OH. Cognitive assessments were not markedly different between groups. After 8.6 years, 195 (59.3%) of the participants had died, and delayed vs no OH was associated with twice the risk of all-cause mortality, HR 2.15 (95% CI 1.12-4.12). Transient classical OH was associated with reduced mortality, HR 0.58 (95% CI 0.33-0.99), but not after multiple adjustments, and continuous classical OH was not associated with mortality. OH may have different implications for morbidity and mortality in 85-year-olds compared with younger populations.

Assessing the impact of novel risk loci on Alzheimer's and Parkinson's diseases in a Chinese Han cohort

Background

Overwhelming evidence points to that genetic factors contributing to the development of Alzheimer's disease (AD) and Parkinson's disease (PD). Genome-Wide Association Study (GWAS) has come a long way in the last decade. So far, a large number of GWAS studies have been published on neurological diseases and many other diseases, providing us with a wealth of genetic information and unique biological insights.

Methods

Genomic DNA was extracted from both patients' and controls' peripheral blood samples utilizing the Blood Genome Extraction Kit. Single nucleotide polymorphisms (SNPs) were genotyped employing the enhanced multiple ligase detection reaction (iMLDR) technology.

Results

A case-control study was conducted, involving 211 AD patients, 508 PD patients (including 117 with dementia), and 412 healthy individuals. Age and sex stratification analysis revealed that rs871269/TNIP1 was associated with LOAD (p = 0.035), and rs5011436/TMEM106B was associated with AD in males (p = 0.044) in the genotype model. In the allele model, rs871269/TNIP1 was found to be associated with PD in the Chinese Han population (p = 0.0035, OR 0.741, 95% CI 0.559-0.983), and rs708382/GRN was identified as a risk factor for Parkinson's disease dementia (PDD) in the Chinese Han population (p = 0.004, odds ratio (OR) 0.354, 95% confidence interval (CI) 0.171-0.733). However, no significant associations with AD or PD were observed for the remaining four loci (rs113020870/AGRN, rs6891966/HAVCR2, rs2452170/NTN5, rs1761461/LILRB2) in terms of allele or genotype frequencies.

Conclusion

This study identifies rs871269/TNIP1 as a potential risk factor for both LOAD and PD, rs708382/GRN as a risk factor for PDD, and rs5011436/TMEM106B as associated with AD in males when stratified by age.

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.

Genetics of Neurogenic Orthostatic Hypotension in Parkinson’s Disease, Results from a Cross-Sectional In Silico Study

The genetic basis of Neurogenic Orthostatic Hypotension (NOH) in Parkinson’s disease (PD) has been inadequately explored. In a cross-sectional study, we examined the association between NOH and PD-related single-nucleotide polymorphisms (SNPs) and mapped their effects on gene expression and metabolic and signaling pathways. Patients with PD, free from pathological conditions associated with OH, and not taking OH-associated medications were included. NOH was defined as per international guidelines. Logistic regression was used to relate SNPs to NOH. Linkage-disequilibrium analysis, expression quantitative trait loci, and enrichment analysis were used to assess the effects on gene expression and metabolic/signaling pathways. We included 304 PD patients in the study, 35 of whom had NOH (11.5%). NOH was more frequent in patients with SNPs in SNCA, TMEM175, FAM47E-STBD1, CCDC62, SCN3A, MIR4696, SH3GL2, and LZTS3/DDRGK1 and less frequent in those with SNPs in ITGA8, IP6K2, SIPA1L2, NDUFAF2. These SNPs affected gene expression associated with the significant hierarchical central structures of the autonomic nervous system. They influenced several metabolic/signaling pathways, most notably IP3/Ca++ signaling, the PKA-CREB pathway, and the metabolism of fatty acids. These findings provide new insights into the pathophysiology of NOH in PD and may provide targets for future therapies.