scholarly journals High diagnostic performance of independent alpha-synuclein seed amplification assays for detection of early Parkinson’s disease

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Marco J. Russo ◽  
Christina D. Orru ◽  
Luis Concha-Marambio ◽  
Simone Giaisi ◽  
Bradley R. Groveman ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Clinical Diagnosis ◽  
Diagnostic Performance ◽  
De Novo ◽  
Alpha Synuclein ◽  
Diagnostic Tools ◽  
Dat Spect ◽  
Progression Markers ◽  
Early Parkinson’S Disease

AbstractAlpha-synuclein seed amplification assays (αSyn-SAAs) are promising diagnostic tools for Parkinson’s disease (PD) and related synucleinopathies. They enable detection of seeding-competent alpha-synuclein aggregates in living patients and have shown high diagnostic accuracy in several PD and other synucleinopathy patient cohorts. However, there has been confusion about αSyn-SAAs for their methodology, nomenclature, and relative accuracies when performed by various laboratories. We compared αSyn-SAA results obtained from three independent laboratories to evaluate reproducibility across methodological variations. We utilized the Parkinson’s Progression Markers Initiative (PPMI) cohort, with DATSCAN data available for comparison, since clinical diagnosis of early de novo PD is critical for neuroprotective trials, which often use dopamine transporter imaging to enrich their cohorts. Blinded cerebrospinal fluid (CSF) samples for a randomly selected subset of PPMI subjects (30 PD, 30 HC, and 20 SWEDD), from both baseline and year 3 collections for the PD and HC groups (140 total CSF samples) were analyzed in parallel by each lab according to their own established and optimized αSyn-SAA protocols. The αSyn-SAA results were remarkably similar across laboratories, displaying high diagnostic performance (sensitivity ranging from 86 to 96% and specificity from 93 to 100%). The assays were also concordant for samples with results that differed from clinical diagnosis, including 2 PD patients determined to be clinically inconsistent with PD at later time points. All three assays also detected 2 SWEDD subjects as αSyn-SAA positive who later developed PD with abnormal DAT-SPECT. These multi-laboratory results confirm the reproducibility and value of αSyn-SAA as diagnostic tools, illustrate reproducibility of the assay in expert hands, and suggest that αSyn-SAA has potential to provide earlier diagnosis with comparable or superior accuracy to existing methods.

scholarly journals Value of Clinical Signs in Identifying Patients with Scans without Evidence of Dopaminergic Deficit (SWEDD)

2020 ◽  
Vol 10 (4) ◽  
pp. 1561-1569 ◽  
Author(s):  
Sven R. Suwijn ◽  
Hamdia Samim ◽  
Carsten Eggers ◽  
Alberto J. Espay ◽  
Susan Fox ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Clinical Diagnosis ◽  
Clinical Features ◽  
Spect Imaging ◽  
Emission Computed Tomography ◽  
Test Accuracy ◽  
Dat Spect ◽  
Nigrostriatal Degeneration ◽  
Early Parkinson’S Disease

Background: In clinical trials that recruited patients with early Parkinson’s disease (PD), 4–15% of the participants with a clinical diagnosis of PD had normal dopamine transporter single photon emission computed tomography (DAT SPECT) scans, also called “scans without evidence of dopaminergic deficit” (SWEDD). Objective: To investigate in patients with a clinical diagnosis of PD, if specific clinical features are useful to distinguish patients with nigrostriatal degeneration from those that have no nigrostriatal degeneration. Methods: We performed a diagnostic test accuracy study. Patients that participated in the Levodopa in Early Parkinson’s disease trial, a clinical trial in patients with early PD, were asked to participate if they had not undergone DAT SPECT imaging earlier. The index tests were specific clinical features that were videotaped. A panel of six neurologists in training (NT), six general neurologists (GN), and six movement disorders experts (MDE) received a batch of ten videos consisting of all SWEDD subjects and a random sample of patients with abnormal DAT SPECT scans. The raters analyzed the videos for presence of specific signs and if they suspected the patient to have SWEDD. The reference test was visually assessed DAT SPECT imaging. Results: Of a total of 87 participants, three subjects were SWEDDs (3.4%). The overall intraclass correlation coefficient (ICC) of the Parkinsonian signs was poor to moderate with ICCs ranging from 0.14 to 0.67. NT correctly identified 50.0% of the SWEDD subjects, GN 33.3%, and MDE 66.7%. Conclusion: Our study suggests that the selected videotaped clinical features cannot reliably distinguish patients with a clinical diagnosis of PD and an abnormal DAT SPECT from patients with clinical PD and a SWEDD.

Asymmetric Dopaminergic Dysfunction in Brain-First versus Body-First Parkinson’s Disease Subtypes

2021 ◽  
pp. 1-11
Author(s):  
Karoline Knudsen ◽  
Tatyana D. Fedorova ◽  
Jacob Horsager ◽  
Katrine B. Andersen ◽  
Casper Skjærbæk ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
De Novo ◽  
Specific Binding ◽  
Asymmetry Index ◽  
The Body ◽  
Specific Binding Ratio ◽  
Dat Spect ◽  
Vagal Innervation ◽  
Nigrostriatal Degeneration

Background: We have hypothesized that Parkinson’s disease (PD) comprises two subtypes. Brain-first, where pathogenic α-synuclein initially forms unilaterally in one hemisphere leading to asymmetric nigrostriatal degeneration, and body-first with initial enteric pathology, which spreads through overlapping vagal innervation leading to more symmetric brainstem involvement and hence more symmetric nigrostriatal degeneration. Isolated REM sleep behaviour disorder has been identified as a strong marker of the body-first type. Objective: To analyse striatal asymmetry in [18F]FDOPA PET and [123I]FP-CIT DaT SPECT data from iRBD patients, de novo PD patients with RBD (PD +RBD) and de novo PD patients without RBD (PD - RBD). These groups were defined as prodromal body-first, de novo body-first, and de novo brain-first, respectively. Methods: We included [18F]FDOPA PET scans from 21 iRBD patients, 11 de novo PD +RBD, 22 de novo PD - RBD, and 18 controls subjects. Also, [123I]FP-CIT DaT SPECT data from iRBD and de novo PD patients with unknown RBD status from the PPPMI dataset was analysed. Lowest putamen specific binding ratio and putamen asymmetry index (AI) was defined. Results: Nigrostriatal degeneration was significantly more symmetric in patients with RBD versus patients without RBD or with unknown RBD status in both FDOPA (p = 0.001) and DaT SPECT (p = 0.001) datasets. Conclusion: iRBD subjects and de novo PD +RBD patients present with significantly more symmetric nigrostriatal dopaminergic degeneration compared to de novo PD - RBD patients. The results support the hypothesis that body-first PD is characterized by more symmetric distribution most likely due to more symmetric propagation of pathogenic α-synuclein compared to brain-first PD.

scholarly journals The Prion-Like Spreading of Alpha-Synuclein in Parkinson’s Disease: Update on Models and Hypotheses

2021 ◽  
Vol 22 (15) ◽  
pp. 8338
Author(s):  
Asad Jan ◽  
Nádia Pereira Gonçalves ◽  
Christian Bjerggaard Vaegter ◽  
Poul Henning Jensen ◽  
Nelson Ferreira
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Molecular Mechanisms ◽  
De Novo ◽  
Alpha Synuclein ◽  
Experimental Models ◽  
Cellular Factors ◽  
Recent Developments ◽  
Novel Targets ◽  
Presynaptic Protein

The pathological aggregation of the presynaptic protein α-synuclein (α-syn) and propagation through synaptically coupled neuroanatomical tracts is increasingly thought to underlie the pathophysiological progression of Parkinson’s disease (PD) and related synucleinopathies. Although the precise molecular mechanisms responsible for the spreading of pathological α-syn accumulation in the CNS are not fully understood, growing evidence suggests that de novo α-syn misfolding and/or neuronal internalization of aggregated α-syn facilitates conformational templating of endogenous α-syn monomers in a mechanism reminiscent of prions. A refined understanding of the biochemical and cellular factors mediating the pathological neuron-to-neuron propagation of misfolded α-syn will potentially elucidate the etiology of PD and unravel novel targets for therapeutic intervention. Here, we discuss recent developments on the hypothesis regarding trans-synaptic propagation of α-syn pathology in the context of neuronal vulnerability and highlight the potential utility of novel experimental models of synucleinopathies.

scholarly journals Sex Differences in Cognitive Changes in De Novo Parkinson’s Disease

2019 ◽  
Vol 26 (2) ◽  
pp. 241-249 ◽  
Author(s):  
Ece Bayram ◽  
Sarah J. Banks ◽  
Guogen Shan ◽  
Nikki Kaplan ◽  
Jessica Z.K. Caldwell
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Sex Differences ◽  
Verbal Memory ◽  
Healthy Aging ◽  
De Novo ◽  
Cognitive Changes ◽  
Progression Markers ◽  
Cognitively Intact

AbstractObjective:To evaluate the sex differences in cognitive course over 4 years in Parkinson’s disease (PD) patients with and without mild cognitive impairment (MCI) compared to controls.Methods:Four-year longitudinal cognitive scores of 257 cognitively intact PD, 167 PD-MCI, and 140 controls from the Parkinson’s Progression Markers Initiative were included. Longitudinal scores of men and women, and PD with and without MCI were compared.Results:Women had better verbal memory, men had better visuospatial function. There was no interaction between sex, diagnostic group, and/or time (4-year follow-up period).Conclusions:Sex differences in cognitive course in de novo PD are similar to healthy aging. Cognitive decline rates in PD with and without MCI are similar for the first 4 years of PD.

scholarly journals Predicting the onset of freezing of gait in de novo Parkinson’s disease

2021 ◽  
Author(s):  
Fengting Wang ◽  
Yixin Pan ◽  
Miao Zhang ◽  
Kejia Hu
Keyword(s):  
Risk Factors ◽  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
De Novo ◽  
Freezing Of Gait ◽  
Poor Quality ◽  
Csf Biomarkers ◽  
Genetic Characteristics ◽  
Progression Markers ◽  
Independent Risk Factors

AbstractFreezing of gait (FoG) is a debilitating symptom of Parkinson’s disease (PD) related to higher risks of falls and poor quality of life. In this study, we predicted the onset of FoG in PD patients using a battery of risk factors from patients enrolled in the Parkinson’s Progression Markers Initiative (PPMI) cohort. The endpoint was the presence of FoG, which was assessed every year during the five-year follow-up visit. Overall, 212 PD patients were included in analysis. Seventy patients (33.0%) developed FoG during the visit (pre-FoG group). Age, bradykinesia, TD/PIGD classification, fatigue, cognitive impairment, impaired autonomic functions and sleep disorder were found to be significantly different in patients from pre-FoG and non-FoG groups at baseline. The logistic regression model showed that motor factors such as TD/PIGD classification (OR = 2.67, 95% CI = 1.41-5.09), MDS-UPDRS part III score (OR = 1.05, 95% CI = 1.01-1.09) were associated with FoG occurrence. Several indicators representing non-motor symptoms such as SDMT total score (OR = 0.95, 95% CI = 0.91-0.98), HVLT immediate/Total recall (OR = 0.91, 95% CI = 0.86-0.97), MOCA (OR = 0.87, 95% CI = 0.76-0.99), Epworth Sleepiness Scale (OR = 1.13, 95% CI = 1.03-1.24), fatigue(OR = 1.98, 95% CI = 1.32-3.06), SCOPA-AUT gastrointestinal score (OR = 1.27, 95% CI = 1.09-1.49) and SCOPA-AUT urinary score (OR = 1.18, 95% CI = 1.06-1.32) were found to have the predictive value. PD patients that developed FoG showed a significant reduction of DAT uptake in the striatum. However, no difference at baseline was observed in genetic characteristics and CSF biomarkers between the two patient sets. Our model indicated that TD/PIGD classification, MDS-UPDRS total score, and Symbol Digit Modalities score were independent risk factors for the onset of FoG in PD patients. In conclusion, the combination of motor and non-motor features including the akinetic subtype and poor cognitive functions should be considered in identifying PD patients with high risks of FoG onset.

scholarly journals Evaluating dopamine transporter imaging as an enrichment biomarker in a phase 2 Parkinson’s disease trial

BMC Neurology ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
R. Matthew Hutchison ◽  
Karleyton C. Evans ◽  
Tara Fox ◽  
Minhua Yang ◽  
Jerome Barakos ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Clinical Trial ◽  
Parkinson's Disease ◽  
Dopamine Transporter ◽  
Single Photon ◽  
Photon Emission ◽  
Alpha Synuclein ◽  
Emission Computed Tomography ◽  
Phase 2 ◽  
Dat Spect

Abstract Background Dopamine transporter single-photon emission computed tomography (DaT-SPECT) can quantify the functional integrity of the dopaminergic nerve terminals and has been suggested as an imaging modality to verify the clinical diagnosis of Parkinson’s disease (PD). Depending on the stage of progression, approximately 5–15% of participants clinically diagnosed with idiopathic PD have been observed in previous studies to have normal DaT-SPECT patterns. However, the utility of DaT-SPECT in enhancing early PD participant selection in a global, multicenter clinical trial of a potentially disease-modifying therapy is not well understood. Methods The SPARK clinical trial was a phase 2 trial of cinpanemab, a monoclonal antibody against alpha-synuclein, in participants with early PD. DaT-SPECT was performed at screening to select participants with DaT-SPECT patterns consistent with degenerative parkinsonism. Acquisition was harmonised across 82 sites. Images were reconstructed and qualitatively read at a central laboratory by blinded neuroradiologists for inclusion prior to automated quantitative analysis. Results In total, 482 unique participants were screened between January 2018 and May 2019; 3.8% (15/398) of imaged participants were excluded owing to negative DaT-SPECT findings (i.e., scans without evidence of dopaminergic deficit [SWEDD]). Conclusion A smaller proportion of SPARK participants were excluded owing to SWEDD status upon DaT-SPECT screening than has been reported in prior studies. Further research is needed to understand the reasons for the low SWEDD rate in this study and whether these results are generalisable to future studies. If supported, the radiation risks, imaging costs, and operational burden of DaT-SPECT for enrichment may be mitigated by clinical assessment and other study design aspects. Trial registration ClinicalTrials.gov identifier: NCT03318523. Date submitted: October 19, 2017. First Posted: October 24, 2017.

scholarly journals Network structure of brain atrophy in de novo Parkinson's disease

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Yashar Zeighami ◽  
Miguel Ulla ◽  
Yasser Iturria-Medina ◽  
Mahsa Dadar ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Medial Temporal Lobe ◽  
Healthy Aging ◽  
De Novo ◽  
Progression Markers ◽  
Magnetic Resonance Imaging Mri ◽  
Cortical Regions ◽  
Clinical Measures ◽  
Deformation Based Morphometry

We mapped the distribution of atrophy in Parkinson's disease (PD) using magnetic resonance imaging (MRI) and clinical data from 232 PD patients and 117 controls from the Parkinson's Progression Markers Initiative. Deformation-based morphometry and independent component analysis identified PD-specific atrophy in the midbrain, basal ganglia, basal forebrain, medial temporal lobe, and discrete cortical regions. The degree of atrophy reflected clinical measures of disease severity. The spatial pattern of atrophy demonstrated overlap with intrinsic networks present in healthy brain, as derived from functional MRI. Moreover, the degree of atrophy in each brain region reflected its functional and anatomical proximity to a presumed disease epicenter in the substantia nigra, compatible with a trans-neuronal spread of the disease. These results support a network-spread mechanism in PD. Finally, the atrophy pattern in PD was also seen in healthy aging, where it also correlated with the loss of striatal dopaminergic innervation.

scholarly journals Longitudinal Change of Clinical and Biological Measures in Early Parkinson's Disease: Parkinson's Progression Markers Initiative Cohort

2018 ◽  
Vol 33 (5) ◽  
pp. 771-782 ◽  
Author(s):  
Tanya Simuni ◽  
Andrew Siderowf ◽  
Shirley Lasch ◽  
Chris S. Coffey ◽  
Chelsea Caspell-Garcia ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Longitudinal Change ◽  
Progression Markers ◽  
Early Parkinson’S Disease
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