Search

BackgroundThe criteria for PD-MCI allow the use of global cognitive tests. Their predictive value for conversion from PD-MCI to PDD, especially compared to comprehensive neuropsychological assessment, is unknown.MethodsThe MDS PD-MCI Study Group combined four datasets containing global cognitive tests as well as a comprehensive neuropsychological assessment to define PD-MCI (n = 467). Risk for developing PDD was examined using a Cox model. Global cognitive tests were compared to neuropsychological test batteries (Level I&II) in determining risk for PDD.ResultsPD-MCI based on a global cognitive test (MMSE or MoCA) increases the hazard for developing PDD (respectively HR = 2.57, P = 0.001; HR = 4.14, P =

INTRODUCTION: Recent work suggests that amyloid beta (Aβ) positron emission tomography (PET) tracer uptake shortly after injection ("early phase") reflects brain metabolism and perfusion. We assessed this modality in a predominantly amyloid‐negative neurodegenerative condition, Parkinson's disease (PD), and hypothesized that early‐phase 18F‐florbetaben (eFBB) uptake would reproduce characteristic hypometabolism and hypoperfusion patterns associated with cognitive decline in PD. METHODS: One hundred fifteen PD patients across the spectrum of cognitive impairment underwent dual‐phase Aβ PET, structural and arterial spin labeling (ASL) magnetic resonance imaging (MRI), and neuropsychological assessments. Multiple linear regression models compared eFBB uptake to cognitive performance and ASL MRI perfusion. RESULTS: Reduced eFBB uptake was associated with cognitive performance in brain regions previously linked to hypometabolism‐associated cognitive decline in PD, independent of amyloid status. Furthermore, eFBB uptake correlated with cerebral perfusion across widespread regions. DISCUSSION: EFBB uptake is a potential surrogate measure for cerebral perfusion/metabolism. A dual‐phase PET imaging approach may serve as a clinical tool for assessing cognitive impairment. Highlights: Images taken at amyloid beta (Aβ) positron emission tomography tracer injection may reflect brain perfusion and metabolism.Parkinson's disease (PD) is a predominantly amyloid‐negative condition.Early‐phase florbetaben (eFBB) in PD was associated with cognitive performance.eFBB uptake reflects hypometabolism‐related cognitive decline in PD.eFBB correlated with arterial spin labeling magnetic resonance imaging measured cerebral perfusion.eFBB distinguished dementia from normal cognition and mild cognitive impairment.Findings were independent of late‐phase Aβ burden.Thus, eFBB may serve as a surrogate measure for brain metabolism/perfusion. [ABSTRACT FROM AUTHOR]

We describe the New Zealand Parkinson's Progression Programme (NZP3), its goals, findings, and future plans. To date, 354 people with Parkinson's disease and 89 healthy older controls have participated over a 14-year period. A major focus of the programme has been the characterisation of current cognitive impairment, and the identification of biomarkers for its future emergence in people with Parkinson's. The programme has made significant contributions to the concept of mild cognitive impairment (MCI) in Parkinson's and the development and validation of standardised criteria for it. Brain imaging, both MRI and PET, has also been a focus, showing associations between increasing brain pathology and declining cognitive function. Additional biomarkers such as genetics, fluid biomarkers, eye movement, speech, and quantitative electroencephalography (EEG) are also under investigation. The programme has become a platform supporting many other avenues of research, from investigating the personal impacts of caregiver burden through to national-level epidemiology. To date, the programme has led to multiple journal publications and 17 completed and 9 ongoing PhDs, and many other postgraduate theses. It has led to the development of a skilled core of early-career through to senior researchers and clinicians. We discuss the future directions for the programme. [ABSTRACT FROM AUTHOR]

Emerging evidence suggests that Alzheimer's disease (AD) and Parkinson's disease dementia (PDD) share neurodegenerative mechanisms. We sought to directly compare cerebral perfusion in these two conditions using arterial spin labeling magnetic resonance imaging (ASL-MRI). In total, 17 AD, 20 PDD, and 37 matched healthy controls completed ASL and structural MRI, and comprehensive neuropsychological testing. Alzheimer's disease and PDD perfusion was analyzed by whole-brain voxel-based analysis (to assess absolute blood flow), a priori specified region of interest analysis, and principal component analysis (to generate a network differentiating the two groups). Corrections were made for cerebral atrophy, age, sex, education, and MRI scanner software version. Analysis of absolute blood flow showed no significant differences between AD and PDD. Comparing each group with controls revealed an overlapping, posterior pattern of hypoperfusion, including posterior cingulate gyrus, precuneus, and occipital regions. The perfusion network that differentiated AD and PDD groups identified relative differences in medial temporal lobes (AD

A recent paper, "Parkinson's disease mild cognitive impairment classifications and neurobehavioral symptoms" (McDermott et al., 2017), provides an interesting comparison of the influence of different criteria for Parkinson's disease with mild cognitive impairment (PD-MCI) on progression to dementia (PDD). Unfortunately, McDermott et al. (2017) incorrectly stated that "only 21% of PD-MCI participants (identified with a 1.5 SD cut-off) converted to PDD within four years" (p.6) in our study (Wood et al., 2016). However, the important point made by Wood et al. (2016) was that the proportion of conversions to PDD was 51% when the PD-MCI diagnosis required a minimum of two 1.5 SD impairments within any single cognitive domain, whereas additional PD-MCI patients classified with one impairment at 1.5 SD in each of the two domains (but never two impairments in the same domain) had a non-significant risk of dementia relative to non-MCI patients (11% vs. 6% converted, respectively). Our PDD conversion rate was 38% when combining both 1.5 SD criteria (21/56 PD-MCI patients vs. 4/65 non-MCI patients converted); McDermott et al. (2017) found a 42% conversion rate over three years for similarly described PD-MCI patients (10/24 PD-MCI patients vs. 0/27 non-MCI patients converted). Our study was also part of a multinational study (n = 467) showing that PD-MCI has predictive validity beyond known demographic and PD-specific factors of influence (Hoogland et al., 2017). All three studies found that multiple cognitive domain impairments are common in PD-MCI. Nonetheless, the research community needs to clarify the association between PD-MCI subtypes and, especially, the optimal cognitive markers for dementia risk in PD patients. [ABSTRACT FROM AUTHOR]

Deficits in memory performance have been linked to a wide range of neurological and neuropsychiatric conditions. While many studies have assessed the memory impacts of individual conditions, this study considers a broader perspective by evaluating how memory recall is differentially associated with nine common neuropsychiatric conditions using data drawn from 55 international studies, aggregating 15,883 unique participants aged 15-90. The effects of dementia, mild cognitive impairment, Parkinson's disease, traumatic brain injury, stroke, depression, attention-deficit/hyperactivity disorder (ADHD), schizophrenia, and bipolar disorder on immediate, short-, and long-delay verbal learning and memory (VLM) scores were estimated relative to matched healthy individuals. Random forest models identified age, years of education, and site as important VLM covariates. A Bayesian harmonization approach was used to isolate and remove site effects. Regression estimated the adjusted association of each clinical group with VLM scores. Memory deficits were strongly associated with dementia and schizophrenia ( p < 0.001), while neither depression nor ADHD showed consistent associations with VLM scores ( p > 0.05). Differences associated with clinical conditions were larger for longer delayed recall duration items. By comparing VLM across clinical conditions, this study provides a foundation for enhanced diagnostic precision and offers new insights into disease management of comorbid disorders.

Introduction: Recent work suggests that amyloid beta (Aβ) positron emission tomography (PET) tracer uptake shortly after injection ("early phase") reflects brain metabolism and perfusion. We assessed this modality in a predominantly amyloid-negative neurodegenerative condition, Parkinson's disease (PD), and hypothesized that early-phase 18 F-florbetaben (eFBB) uptake would reproduce characteristic hypometabolism and hypoperfusion patterns associated with cognitive decline in PD., Methods: One hundred fifteen PD patients across the spectrum of cognitive impairment underwent dual-phase Aβ PET, structural and arterial spin labeling (ASL) magnetic resonance imaging (MRI), and neuropsychological assessments. Multiple linear regression models compared eFBB uptake to cognitive performance and ASL MRI perfusion., Results: Reduced eFBB uptake was associated with cognitive performance in brain regions previously linked to hypometabolism-associated cognitive decline in PD, independent of amyloid status. Furthermore, eFBB uptake correlated with cerebral perfusion across widespread regions., Discussion: EFBB uptake is a potential surrogate measure for cerebral perfusion/metabolism. A dual-phase PET imaging approach may serve as a clinical tool for assessing cognitive impairment., Highlights: Images taken at amyloid beta (Aβ) positron emission tomography tracer injection may reflect brain perfusion and metabolism.Parkinson's disease (PD) is a predominantly amyloid-negative condition.Early-phase florbetaben (eFBB) in PD was associated with cognitive performance.eFBB uptake reflects hypometabolism-related cognitive decline in PD.eFBB correlated with arterial spin labeling magnetic resonance imaging measured cerebral perfusion.eFBB distinguished dementia from normal cognition and mild cognitive impairment.Findings were independent of late-phase Aβ burden.Thus, eFBB may serve as a surrogate measure for brain metabolism/perfusion., Competing Interests: The authors declare no conflicts of interest related to this research. The principal author confirms that all authors have read the manuscript, and the paper has not previously been published or is under consideration at another journal. The authors take full responsibility for the data, analyses, and interpretation, and the conduct of the research, and have full access to all the data and the right to publish it. All authors have agreed to the conditions noted on the authorship agreement form., (© 2024 The Author(s). Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring published by Wiley Periodicals LLC on behalf of Alzheimer's Association.)

Movements in people with Parkinson's disease are often hypometric, although we have found that this was not the case in an experimental visually-guided reaching task. We wished to explore our hypotheses that (1) people with Parkinson's disease produce hypometric primary submovements but(2) are able to use visual feedback to accurately reach the target in a single overall movement, and (3) this effect may be greater in memory-guided tasks in which an internal representation of the target location is used instead of a fixation-centered representation of the target.Visually- and memory-guided reaching movements were examined in 22 people with mild to moderate severity Parkinson's disease on medication, along with age-matched and sex-matched controls. Primary submovements were extracted from 5149 movements using a method based upon zero crossings of jerk(3rd derivative of position), with several additional criteria to minimize the detection of submovements due to noise or tremor.There was no difference in the end position of the overall reaching movement between the two groups, although the movement was smaller in the memory-guided task. In contrast,the gain of the primary submovement was smaller in the Parkinson's disease group than the control group, with this difference being greater on the memory-guided task. There was no task effect on the primary submovement gain in the control group.Our results show that the underlying primary submovement in visually-guided movements in people with Parkinson's disease is hypometric, and that the degree of hypometria is even greater in memory-guided movements.