Lifelong bilingualism may contribute to cognitive reserve (CR) in neurodegenerative diseases as shown by a delay of the age at symptom onset in bilinguals with Alzheimer’s disease (AD) and Mild ...Cognitive Impairment (MCI). However, some studies have failed to show this bilingual advantage, suggesting that it might depend on the type and degree of bilingualism. In the present study, we tested the hypothesis that active bilingualism, defined as the continuous use of the two languages as opposed to second language exposition only, may protect against cognitive decline. Moreover, we investigated whether bilingualism as a CR factor may be explained by an advantage within the executive control (EC) system. To do so, we collected clinical measures (age at onset of cognitive symptoms, age at the first medical visit for cognitive impairments, and age at diagnosis) in patients with MCI and patients with AD with different degrees of language experience and usage of Catalan and Spanish. Additionally, all participants were tested on four EC tasks and one long-term memory recognition task. First, results from multiple regression analyses showed that active bilingualism was a significant predictor of delay in the age at onset for all the clinical measures in MCI, but not AD patients. Second, the effect of active bilingualism was independent of occupation, educational level and job attainment across the individuals’ lifespan. Finally, although we did not find an effect of active bilingualism across all EC tasks, we did find an effect for conflict resolution. These results are discussed in the context of CR hypotheses, suggesting that compensatory mechanisms may play a role in protecting against cognitive decline.
•We tested whether active bilingualism may protect against cognitive decline.•We tested patients with different degrees of language experience and usage.•We collected clinical measures and performance in executive control tasks.•Active bilingualism was a predictor of delay in the age at onset only in MCI.
Pause duration analysis is a common feature in the study of discourse in Alzheimer’s disease (AD) since this patient group has shown a consistent trend for longer pauses in comparison to healthy ...controls. This speech feature may also be helpful for early detection; however, studies involving patients at the pre-clinical, high-risk phase of amnestic mild cognitive impairment (aMCI) have yielded varying results.
To characterize the probability density distribution of speech pause durations in 26 patients with AD, 57 amnestic multi-domain amnestic MCI patients (29 with memory encoding deficits, a-mdMCI-E, and 28 with retrieval impairment only, a-mdMCI-R) and 29 healthy controls (HC) in order assess whether there are significant differences between them. To explore the potential differences in pause production between patients with a-mdMCI-E and a-mdMCI-R, as the former are considered to be at higher risk of progressing to dementia.
The 112 picture-based oral narratives obtained were manually transcribed and annotated for the automatic extraction and analysis of pause durations. Different probability distributions were tested for the fitting of pause durations while truncating shorter ranges. Recent findings in the field of Statistics were considered in order to avoid the inherent methodological uncertainty that this type of analysis entails by addressing the question of temporal thresholding and its potential repercussions on inter-annotator reliability in manual transcriptions.
A lognormal distribution (LND) explained the distribution of pause duration for all groups. Its fitted parameters (μ, σ) followed a gradation from the group with shorter durations and a higher tendency to produce short pauses (HC) to the group with longer pause durations and a considerably higher tendency to produce long pauses with greater variance (AD). Importantly, a-mdMCI-E produced significantly longer pauses and with greater variability than their a-mdMCI-R counterparts (α=0.05).
We report significant differences at the group level in pause distribution across all groups of study that could be used in future diagnostic tools and discuss the clinical implications of these findings, particularly regarding the characterization of a-mdMCI.
•Pause duration distribution differentiates two groups with MCI at risk of AD.•Lognormal distribution explains distribution of pause duration; differentiates clinical groups.•Principled statistical framework for estimation of optimal minimal pause duration threshold.•Characterization of probability density distribution of speech pause durations in MCI and AD.
Recent evidence indicates a link between Parkinson's Disease (PD) and the expression of a-synuclein (SNCA) isoforms with different 3' untranslated regions (3'UTRs). Yet, the post-transcriptional ...mechanisms regulating SNCA expression are unknown. Using a large-scale in vitro /in silico screening we identified RNA-binding proteins (RBPs) that interact with SNCA 3' UTRs. We identified two RBPs, ELAVL1 and TIAR, that bind with high affinity to the most abundant and translationally active 3' UTR isoform (575 nt). Knockdown and overexpression experiments indicate that both ELAVL1 and TIAR positively regulate endogenous SNCA in vivo. The mechanism of regulation implies mRNA stabilization as well as enhancement of translation in the case of TIAR. We observed significant alteration of both TIAR and ELAVL1 expression in motor cortex of post-mortem brain donors and primary cultured fibroblast from patients affected by PD and Multiple System Atrophy (MSA). Moreover, trans expression quantitative trait loci (trans-eQTLs) analysis revealed that a group of single nucleotide polymorphisms (SNPs) in TIAR genomic locus influences SNCA expression in two different brain areas, nucleus accumbens and hippocampus. Our study sheds light on the 3' UTR-mediated regulation of SNCA and its link with PD pathogenesis, thus opening up new avenues for investigation of post-transcriptional mechanisms in neurodegeneration.
Neuroinflammation is a potential player in neurodegenerative conditions, particularly the aggressive ones, such as multiple system atrophy (MSA). Previous reports on cytokine levels in MSA using ...serum or cerebrospinal fluid (CSF) have been inconsistent, including small samples and a limited number of cytokines, often without comparison to Parkinson's disease (PD), a main MSA differential diagnosis.
Cross-sectional study of CSF levels of 38 cytokines using a multiplex assay in 73 participants: 39 MSA patients (19 with parkinsonian type MSAp, 20 with cerebellar type MSAc; 31 probable, 8 possible), 19 PD patients and 15 neurologically unimpaired controls. None of the participants was under non-steroidal anti-inflammatory drugs at the time of the lumbar puncture.
There were not significant differences in sex and age among participants. In global non-parametric comparisons FDR-corrected for multiple comparisons, CSF levels of 5 cytokines (FGF-2, IL-10, MCP-3, IL-12p40, MDC) differed among the three groups. In pair-wise FDR-corrected non-parametric comparisons 12 cytokines (FGF-2, eotaxin, fractalkine, IFN-α2, IL-10, MCP-3, IL-12p40, MDC, IL-17, IL-7, MIP-1β, TNF-α) were significantly higher in MSA vs. non-MSA cases (PD + controls pooled together). Of these, MCP-3 and MDC were the most significant ones, also differed in MSA vs. PD, and were significant MSA-predictors in binary logistic regression models and ROC curves adjusted for age. CSF levels of fractalkine and MIP-1α showed a strong and significant positive correlation with UMSARS-2 scores.
Increased CSF levels of cytokines such as MCP-3, MDC, fractalkine and MIP-1α deserve consideration as potential diagnostic or severity biomarkers of MSA.
•CSF levels of 12 cytokines were higher in MSA (n = 39) vs. PD + controls (n = 19 & 15).•Younger age and increasing CSF levels of MCP-3 and MDC were MSA predictors in adjusted models.•CSF levels of fractalkine and MIP-1α correlated with UMSARS-2 scores.•CSF levels of these cytokines might be diagnostic or severity MSA biomarkers.
Abstract Impulsive and compulsive behaviors (ICBs) have been reported to occur frequently in Parkinson's disease (PD) and include impulse control disorders (ICDs), punding and dopamine dysregulation ...syndrome (SSD). We report on the outcomes of 25 PD patients who developed ICBs. Information was collected on changes in parkinsonian and psychiatric medication follow-up (median = 12.1 months). At time 1, only 18 patients (72%) were taking dopamine agonists (DA). At time 2, fifteen patients (83.33%) either discontinued or decreased their DA treatment. Of these patients, thirteen (86.67%) reported experiencing full or partial remission of their ICBs symptoms. When analyzing separately the 11 patients with punding, these symptoms remained unchanged in 9 patients (81.82%) independently of changes in dopaminergic drugs. In conclusion, the current study suggests that there are clear similarities, but also important differences, between punding and ICDs over time. Pathological gambling, binge or compulsive eating, pathological hypersexuality and compulsive shopping in PD were robustly associated with the use of DA but the relationship between dopaminergic medications and punding is less clear. It is important to determine if other treatment strategies may be effective for punding in PD.
Multiple system atrophy (MSA) is a rare oligodendroglial synucleinopathy of unknown etiopathogenesis including two major clinical variants with predominant parkinsonism (MSA-P) or cerebellar ...dysfunction (MSA-C).
To identify novel disease mechanisms we performed a blood transcriptomic study investigating differential gene expression changes and biological process alterations in MSA and its clinical subtypes.
We compared the transcriptome from rigorously gender and age-balanced groups of 10 probable MSA-P, 10 probable MSA-C cases, 10 controls from the Catalan MSA Registry (CMSAR), and 10 Parkinson Disease (PD) patients.
Gene set enrichment analyses showed prominent positive enrichment in processes related to immunity and inflammation in all groups, and a negative enrichment in cell differentiation and development of the nervous system in both MSA-P and PD, in contrast to protein translation and processing in MSA-C. Gene set enrichment analysis using expression patterns in different brain regions as a reference also showed distinct results between the different synucleinopathies.
In line with the two major phenotypes described in the clinic, our data suggest that gene expression and biological processes might be differentially affected in MSA-P and MSA-C. Future studies using larger sample sizes are warranted to confirm these results.
Blood homocysteine appears to be increased in Parkinson's disease (PD) and may play a role in the development and progression of this disorder. However, the specific contribution of abnormal ...homocysteine levels to cortical degeneration in PD remains elusive.
To characterize the cortical structural correlates of homocysteine levels in PD.
From the COPPADIS cohort, we identified a subset of PD patients and healthy controls (HC) with available homocysteine and imaging data. Surface-based vertex-wise multiple regression analyses were performed to investigate the cortical macrostructural (cortical thinning) and microstructural (increased intracortical diffusivity) correlates of homocysteine levels in this sample.
A total of 137 PD patients and 43 HC were included. Homocysteine levels were increased in the PD group (t = −2.2, p = 0.03), correlating in turn with cognitive performance (r = −0.2, p = 0.03). Homocysteine in PD was also associated with frontal cortical thinning and, in a subset of patients with available DTI data, with microstructural damage in frontal and posterior-cortical regions (p < 0.05 Monte-Carlo corrected).
Homocysteine in PD appears to be associated with cognitive performance and structural damage in the cerebral cortex. These findings not only reinforce the presence and importance of cortical degeneration in PD, but also suggest that homocysteine plays a role among the multiple pathological processes thought to be involved in its development.
•Parkinson's disease (PD) patients appear to show increased homocysteine levels.•Homocysteine correlated in turn with cognitive performance in our PD sample.•Homocysteine was also associated with cortical macro- and microstructural alterations.•This metabolic marker may play a role in cortical degeneration in the PD population.
Identifying modifiable risk factors for cognitive impairment in the early stages of Parkinson's disease (PD) and estimating their impact on cognitive status may help prevent dementia (PDD) and the ...design of cognitive trials.
Using a standard approach for the assessment of global cognition in PD and controlling for the effects of age, education and disease duration, we explored the associations between cognitive status, comorbidities, metabolic variables and lifestyle variables in 533 PD participants from the COPPADIS study.
Among the overall sample, 21% of participants were classified as PD-MCI (n = 114) and 4% as PDD (n = 26). The prevalence of hypertension, diabetes and dyslipidemia was significantly higher in cognitively impaired patients while no between-group differences were found for smoking, alcohol intake or use of supplementary vitamins. Better cognitive scores were significantly associated with regular physical exercise (p < 0.05) and cognitive stimulation (< 0.01). Cognitive performance was negatively associated with interleukin 2 (Il2) (p < 0.05), Il6 (p < 0.05), iron (p < 0.05), and homocysteine (p < 0.005) levels, and positively associated with vitamin B12 levels (p < 0.005).
We extend previous findings regarding the positive and negative influence of various comorbidities and lifestyle factors on cognitive status in early PD patients, and reinforce the need to identify and treat potentially modifiable variables with the intention of exploring the possible improvement of the global cognitive status of patients with PD.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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