Clinical diagnosis of progressive supranuclear palsy: The movement disorder society criteria

A subgroup of multiple system atrophy with rapid decline in vital capacity

INTRODUCTION

Patients with neurodegenerative disorders resulting in progressive dysphagia often require gastrostomy. Pulmonary function tests (PFTs) are crucial in presurgical evaluation; however, reports on pulmonary function in multiple system atrophy (MSA) and progressive supranuclear palsy (PSP) are limited.

MATERIALS AND METHODS

This single-center, retrospective study analyzed the PFT records from patients with MSA and PSP admitted between January 2012 and October 2023.

RESULTS

Data from 104 PFTs in 70 patients with MSA (21 MSA-P, 49 MSA-C) and 29 PFTs in 22 patients with PSP, showed a weak correlation between the percentage of measured vital capacity to the predicted vital capacity (%VC) and disease duration (MSA: -0.34 and PSP: -0.19). The variation in %VC decline was greater in MSA than in PSP, with a rapid progression (%VC < 65 % within 5 years of disease duration) in seven patients with MSA (6 MSA-P and 1 MSA-C).

CONCLUSION

A decline in %VC with disease duration was observed in both MSA and PSP, with greater variation observed in MSA. Notably, a rapid decline in %VC was predominantly observed in patients with MSA-P during the early courses.

Identification of metabolic progression and subtypes in progressive supranuclear palsy by PET molecular imaging

INTRODUCTION

Progressive supranuclear palsy (PSP) is a neurodegenerative disorder with diverse clinical presentations that are linked to tau pathology. Recently, Subtype and Stage Inference (SuStaIn) algorithm, an innovative data-driven method, has been developed to model both the spatial-temporal progression and subtypes of disease. This study explores PSP progression using 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) imaging and the SuStaIn algorithm to identify PSP metabolic progression subtypes and understand disease mechanisms.

METHODS

The study included 72 PSP patients and 70 controls, with an additional 24 PSP patients enrolled as a test set, undergoing FDG-PET, dopamine transporter (DAT) PET, and neuropsychological assessments. The SuStaIn algorithm was employed to analyze the FDG-PET data, identifying progression subtypes and sequences.

RESULTS

Two PSP subtypes were identified: the cortical subtype with early prefrontal hypometabolism and the brainstem subtype with initial midbrain alterations. The cortical subtype displayed greater cognitive impairment and DAT reduction than the brainstem subtype. The test set demonstrates the robustness and reproducibility of the findings. Pathway analysis indicated that disruptions in dopaminergic cortico-basal ganglia pathways are crucial for elucidating the mechanisms of cognitive and behavioral impairment in PSP, leading to the two metabolic progression subtypes.

CONCLUSION

This study identified two spatiotemporal progression subtypes of PSP based on FDG-PET imaging, revealing significant differences in metabolic patterns, striatal dopaminergic uptake, and clinical profiles, particularly cognitive impairments. The findings highlight the crucial role of dopaminergic cortico-basal ganglia pathways in PSP pathophysiology, especially in the cortical subtype, providing insights into PSP heterogeneity and potential avenues for personalized treatments.

Frontotemporal Dementia Differential Diagnosis in Clinical Practice: A Single-Center Retrospective Review of Frontal Behavioral Referrals

Background and Objectives

Many neurodegenerative syndromes present with impairment of frontal networks, especially frontoinsular networks affecting social and emotional cognition. People presenting with frontal network impairments may be considered for a frontotemporal dementia (FTD) diagnosis. We sought to examine the diagnostic mix of patients referred with frontal network impairments to a single cognitive neurology service.

Methods

A retrospective review was conducted of all patients seen between January 2010 and December 2019 at the Eastern Cognitive Disorders Clinic, a quaternary cognitive neurology clinic in Melbourne, Australia. Patients were included if they met the following criteria: (1) were referred for suspected FTD or with a preexisting diagnosis of a FTD syndrome, (2) were referred for 'frontal behaviors' (i.e., disinhibition, disorganization, poor judgment, loss of empathy, apathy) and/or had an informant report of behavior change, and (3) had available referral documents and clinical consensus diagnosis. Referral diagnosis was compared against final diagnosis adjudicated by a consensus multidisciplinary team. Case details including age of symptom onset, Cambridge Behavioural Inventory-Revised scores, psychiatric history, and Charlson Comorbidity Index were compared against the final diagnosis.

Results

In total, 161 patients aged 42-82 years (mean = 64.5, SD = 9.0; 74.5% men) met inclusion criteria. The commonest final diagnosis was a FTD syndrome (44.6%: 26.7% behavioral variant FTD (bvFTD), 9.3% progressive supranuclear palsy, 6.2% semantic dementia, 1.2% corticobasal syndrome, and 1.2% FTD/motor neuron disease). A primary psychiatric disorder (PPD) was the next commonest diagnosis (15.5%), followed by vascular cognitive impairment (VCI, 10.6%), Alzheimer disease (AD, 9.9%), and other neurologic diagnoses (6.2%). A final diagnosis of bvFTD was associated with higher rates of medical comorbidities and more eating behavior abnormalities compared with a diagnosis of PPD. Screening cognitive tests and preexisting psychiatric history did not distinguish these 2 groups.

Discussion

A broad spectrum of neurologic and psychiatric disorders may present with impairments to frontal networks. Almost half of patients referred had a final FTD syndrome diagnosis, with bvFTD the commonest final diagnosis. People with PPD, VCI, and AD present with similar clinical profiles but are distinguishable using MRI and FDG-PET imaging. Medical and psychiatric comorbidities are common in people with bvFTD.

Pragmatic algorithm for visual assessment of 4-Repeat tauopathies in [18F]PI-2620 PET Scans

AIM

Standardized evaluation of [18F]PI-2620 tau-PET scans in 4R-tauopathies represents an unmet need in clinical practice. This study aims to investigate the effectiveness of visual evaluation of [18F]PI-2620 images for diagnosing 4R-tauopathies and to develop a straight-forward reading algorithm to improve objectivity and data reproducibility.

METHODS

A total of 83 individuals with [18F]PI-2620 PET scans were included. Participants were classified as probable 4R-tauopathies (n = 29), Alzheimer's disease (AD) (n = 20), α-synucleinopathies (n = 15), and healthy controls (n = 19) based on clinical criteria. Visual assessment of tau-PET scans (choice: 4R-tauopathy, AD-tauopathy, no-tauopathy) was conducted using either 20-40-minute or 40-60-minute intervals, with raw (common) and cerebellar grey matter scaled standardized reading settings (intensity-scaled). Two readers evaluated scans independently and blinded, with a third reader providing consensus in case of discrepant primary evaluation. A regional analysis was performed using the cortex, basal ganglia, midbrain, and dentate nucleus. Sensitivity, specificity, and interrater agreement were calculated for all settings and compared against the visual reads of parametric images (0-60-minutes, distribution volume ratios, DVR).

RESULTS

Patients with 4R-tauopathies in contrast to non-4R-tauopathies were detected at higher sensitivity in the 20-40-minute frame (common: 79%, scaled: 76%) compared to the 40-60-minute frame (common: 55%, scaled: 62%), albeit with reduced specificity in the common setting (20-40-min: 78%, 40-60-min: 95%), which was ameliorated in the intensity-scaled setting (20-40-min: 91%, 40-60-min: 96%). Combined assessment of multiple brain regions did not significantly improve diagnostic sensitivity, compared to assessing the basal ganglia alone (76% each). Evaluation of intensity-scaled parametric images resulted in higher sensitivity compared to intensity-scaled static scans (86% vs. 76%) at similar specificity (89% vs. 91%).

CONCLUSION

Visual reading of [18F]PI-2620 tau-PET scans demonstrated reliable detection of 4R-tauopathies, particularly when standardized processing methods and early imaging windows were employed. Parametric images should be preferred for visual assessment of 4R-tauopathies.

Flattened red nucleus in progressive supranuclear palsy detected by quantitative susceptibility mapping

INTRODUCTION

Progressive supranuclear palsy (PSP) involves midbrain structures, including the red nucleus (RN), an iron-rich region that appears as a high-contrast area on quantitative susceptibility mapping (QSM). RN may serve as a promising biomarker for differentiating parkinsonism. However, RN deformation in PSP remains elusive. This study aimed to evaluate RN deformation in PSP using coronal QSM images and compare them with those of Parkinson's disease (PD) and healthy controls (HC).

METHODS

We evaluated the QSM images of 22 patients with PSP, 37 patients with PD, and 43 HC. We developed a grading system to assess RN deformation on coronal QSM images and classified them into three grades. The midbrain and RN volumes were extracted using distinct approaches, and their relationship with grading was investigated. For validation, coronal QSM images of 16 PSP patients from a different institution were assessed.

RESULTS

In PSP, 59 % of the patients displayed a flattened RN of grade 3, which we termed a Rice-Grain Appearance. The volume reductions in midbrain and RN were associated with deformation. Differentiation based on the presence of this appearance yielded a specificity of 1.000 (CI: 1.000-1.000) and sensitivity of 0.591 (0.385-0.796) for distinguishing PSP from others. Secondary dataset also showed that 56 % of patients with PSP were classified as grade 3.

CONCLUSION

In coronal QSM images, the flattened RN shape appears to be specific to PSP compared to PD and HC and may serve as a marker to help differentiate PSP in future clinical settings.

MRI classification of progressive supranuclear palsy, Parkinson disease and controls using deep learning and machine learning algorithms for the identification of regions and tracts of interest as potential biomarkers

BACKGROUND

Quantitative magnetic resonance imaging (MRI) analysis has shown promise in differentiating neurodegenerative Parkinsonian syndromes and has significantly advanced our understanding of diseases like progressive supranuclear palsy (PSP) in recent years.

OBJECTIVE

The aim of this study was to develop, implement and compare MRI analysis algorithms based on artificial intelligence (AI) that can differentiate PSP not only from healthy controls but also from Parkinson disease (PD), by analyzing changes in brain structure and microstructure. Specifically, this study focused on identifying regions of interest (ROIs) and tracts of interest (TOIs) that are crucial for the algorithms to provide clinically relevant performance indices for the distinction between disease variants.

METHODS

MR data comprised diffusion tensor imaging (DTI - tractwise fractional anisotropy statistics (TFAS)) and T1-weighted (T1-w) data (texture analysis of the corpus callosum (CC)). One subject sample with 74 PSP patients and 63 controls was recorded at 3.0T at multiple sites. The other sample came from a single site, consisting of 66 PSP patients, 66 PD patients, and 44 controls, recorded at 1.5T. Four different machine learning algorithms (ML) and a deep learning (DL) neural network approach using Tensor Flow were implemented for the study. The training of the algorithms was performed on 80 % of the data, which included the entire single-site data and parts of the multiple-site data. The validation process was conducted on the remaining data, thereby consistently separating training and validation data.

RESULTS

A random forest algorithm and a DL neural network classified PSP and healthy controls with accuracies of 92 % and 95 %, respectively. Particularly, DTI derived measures for the pons, midbrain tegmentum, superior cerebral peduncle, putamen, and CC contributed to high accuracies. Furthermore, DL neural network classification of PSP and PD with 86 % accuracy showed the importance of 19 structures. The four most important features were DTI derived measures for prefrontal white matter, the fasciculus frontooccipitalis, the midbrain tegmentum, and the CC area II. This DL network achieved a sensitivity of 88 % and specificity of 85 %, resulting in a Youden-index of 0.72.

CONCLUSION

The primary goal of the present study was to compare multiple ML-methods and a DL approach to identify the least necessary set of brain structures to classify PSP vs. controls and PSP vs. PD by ranking them in a hierarchical order of importance. That way, this study demonstrated the potential of AI approaches to MRI as possible diagnostic and scientific tools to differentiate variants of neurodegenerative Parkinsonism.

Iron(ing) out parkinsonisms: The interplay of proteinopathy and ferroptosis in Parkinson's disease and tau-related parkinsonisms

Parkinsonian syndromes are characterised by similar motor-related symptomology resulting from dopaminergic neuron damage. While Parkinson's disease (PD) is the most prevalent parkinsonism, we also focus on two other variants, Progressive supranuclear palsy (PSP) and Corticobasal degeneration (CBD). Due to the clinical similarities of these parkinsonisms, and since definite diagnoses are only possible post-mortem, effective therapies and novel biomarkers of disease are scarce. Thus, we explore the current findings relating to the relationship of parkinsonism proteinopathy (α-synuclein in PD, and tau in PSP/CBD) paralleled to a specific form of cell death, ferroptosis. Ferroptosis is characterised by iron-induced lipid peroxidation and several markers of this pathway have been identified to control intracellular iron fluctuations. However, in parkinsonism, these mechanisms are thought to become dysfunctional. Although both proteinopathies have been linked to ferroptosis, much less is known about ferroptotic cell death and tau in the context of PSP/CBD. Interestingly, clinical trials targeting iron have recently shown conflicting results which begs to question the complexity of the ferroptotic pathway and alludes to the need for exploring other ferroptosis-related machinery as possible therapeutic targets. Overall, we address the literature gap in parkinsonism proteinopathy and ferroptosis, and its relevance to understanding disease pathophysiology and aetiology.

Clinical trial eligibility in PSP: Population representativeness and potential criteria adjustment based on PSP-NET findings

BACKGROUND

Progressive Supranuclear Palsy (PSP) is a rare, heterogeneous neurodegenerative disease for which no treatment is currently available. In the context of clinical trials, the representativeness of the included patients is crucial for the generalizability of the results. Herein, we present results from a multicenter perspective study to identify the most restrictive criteria for patient selection and to assess the representativeness of eligible patients.

METHODS

we enrolled 221 PSP patients diagnosed according to the MDS clinical criteria. All patients were screened with a set of inclusion and exclusion criteria based on previous and ongoing clinical trials in PSP and underwent motor and cognitive evaluation with the Montreal Cognitive Assessment battery and the PSP rating scale, respectively. Then, clinical features of eligible and non-eligible patients were compared at baseline and after 15,93 ± 8,77 months follow up.

RESULTS

Eligible (28 patients, 12,6 %) patients were younger, showed shorter disease duration and lower severity but similar distribution of PSP phenotype and disease progression rates compared to non-eligible patients. The most restrictive non-modifiable criteria were independent gait, disease duration and cognitive status. Willingness to undergo lumbar puncture and treatment stability for previous 60 days represented potentially modifiable criteria.

CONCLUSION

Overall, PSP eligible for clinical trials are representative of the general PSP population. While motor and cognitive impairment represent the most important non-modifiable barriers to enter a clinical trial, other criteria as willingness to undergo lumbar puncture and treatment stability are potentially modifiable. Specific strategies are discussed to increase the number of eligible patients working on potentially modifiable criteria.

Speech profile in different clinical PSP phenotypes: an acoustic-perceptual study

Progressive supranuclear palsy (PSP) is a neurodegenerative disease with pathological hallmarks and different clinical presentations. Recently, the Movement Disorder Society (MDS) promoted a new classification; specific combinations of the core clinical features identify different phenotypes, including PSP with Richardson's syndrome (PSP-RS) and PSP with predominant parkinsonism (PSP-P). Since speech disorders are very common in PSP, they were included in the MDS-PSP criteria as a supportive clinical feature in the form of hypokinetic, spastic dysarthria. However, little is known about how dysarthria presents across the different PSP variants. The aim of the present study is to evaluate the presence of differences in speech profile in a cohort of PSP-RS and PSP-P patients diagnosed according to the MDS-PSP criteria. Each patient underwent a neurological evaluation and perceptual and acoustic analysis of speech. Disease severity was rated using the Natural History and Neuroprotection in Parkinson plus syndromes-Parkinson plus scale (NNIPPS-PPS), including global score and sub-scores. Twenty-five patients (mean disease duration [standard deviation] = 3.32 [1.79]) were classified as PSP-RS, while sixteen as PSP-P (mean disease duration [standard deviation] = 3.47 [2.00]). These subgroups had homogeneous demographical and clinical characteristics, including disease severity quantified by the NNIPPS-PPS total score. Only the NNIPPS-PPS oculomotor function sub-score significantly differed, being more impaired in PSP-RS patients. No significant differences were found in all speech variables between the two groups. Speech evaluation is not a distinguishing feature of PSP subtypes in mid-stage disease.

Modeling Sporadic Progressive Supranuclear Palsy in 3D Midbrain Organoids: Recapitulating Disease Features for In Vitro Diagnosis and Drug Discovery

OBJECTIVE

Progressive Supranuclear Palsy (PSP) is a severe neurodegenerative disease characterized by tangles of hyperphosphorylated tau protein and tufted astrocytes. Developing treatments for PSP is challenging due to the lack of disease models reproducing its key pathological features. This study aimed to model sporadic PSP-Richardson's syndrome (PSP-RS) using multi-donor midbrain organoids (MOs).

METHODS

The MOs were generated by pooling induced pluripotent stem cells (iPSCs) from 4 patients with sporadic probable PSP-RS and compared them with MOs from 3 healthy control (HC) subjects. We performed comprehensive analyses of MOs over 120 days to assess neuronal death, reactive gliosis, and the accumulation of 4R-tau and hyperphosphorylated tau forms (pThr231, pSer396, pThr181, and pSer202/pThr205 [AT8]) using immunofluorescence microscopy and Western blot. On day 90, immunohistochemical analysis using pSer396 and AT8 antibodies was conducted to assess disease pathology.

RESULTS

PSP-derived MOs showed progressive size reduction compared with HC-derived MOs, linked to upregulated apoptosis-related mRNA markers. Dopaminergic neuron degeneration was marked by decreased tyrosine hydroxylase (TH) and increased neurofilament light chain (NfL). Immunofluorescence and Western blot revealed accumulation of all investigated tau forms with a peak at 90 days, along with a significant rise in GFAP-positive cells in PSP-derived MOs. Immunochemistry confirmed typical PSP histological alterations, such as neurofibrillary tangles and tufted-shaped astrocytes, absent in HC-derived organoids.

INTERPRETATION

We developed a robust in vitro PSP model reproducing the key molecular and histologic features of the disease. This result holds promise for advancing basic and clinical research in PSP, paving the way for in vitro molecular diagnosis and identification of novel therapeutic targets. ANN NEUROL 2025.

A Short Cognitive and Neuropsychiatric Assessment Scale for Progressive Supranuclear Palsy

BACKGROUND

Patients with Progressive Supranuclear Palsy (PSP) suffer from several neuropsychological impairments. These mainly affect the frontal lobe and subcortical brain structures. However, a scale for the assessment of cognitive and neuropsychiatric disability in PSP is still missing.

OBJECTIVES

To create and validate a new scale for cognitive and neuropsychiatric impairment in PSP.

METHODS

The Short Cognitive and Neuropsychiatric (ShoCo) scale was developed containing five items (bradyphrenia, apathy, aphasia, dysexecution and disinhibition). Each item can be categorized into 0 = no deficit, 1 = mild deficit, 2 = moderate deficit and 3 = severe deficit. The total score includes 15 points, 0 meaning no deficit and 15 severe deficits. Cross-sectional and longitudinal data from 201 baseline and 71 follow up patients were analyzed.

RESULTS

Baseline ShoCo scale results were 5.9 ± 2.9. No significant differences between patients with Richardson syndrome (PSP-RS) and variants (vPSP) could be detected in the PSP-ShoCo scale scores (PSP-RS 6.1 ± 3.0, n = 160, vPSP 5.1 ± 2.6, n = 41, P = 0.057). The scale showed good correlation with established scores (eg, Montreal cognitive assessment r = -0.535, P = 0.001). The ShoCo scale showed significant annualized change within the PSP-RS patients (baseline 6.2 ± 2.9, follow up 6.9 ± 3.1, annualized diff. 1.0 ± 3.1, n = 57, P = 0.022).

CONCLUSIONS

The ShoCo scale seems a promising and valid tool to measure specific neuropsychological disabilities of PSP patients in clinical routine and research.

Accuracy and clinical applicability of plasma tau 181 and 217 for Alzheimer's disease diagnosis in a memory clinic cohort

Plasma tau phosphorylated at threonine 181 (p-tau181) and 217 (p-tau217) have demonstrated high accuracy for Alzheimer's disease (AD) diagnosis, defined by CSF/PET amyloid beta (Aβ) positivity, but most studies have been performed in research cohorts, limiting their generalizability. We studied plasma p-tau217 and p-tau181 for CSF Aβ status discrimination in a cohort of consecutive patients attending an academic memory clinic in Spain (July 2019-June 2024). All patients had CSF AD biomarkers performed as part of their routine clinical assessment. Aβ positivity was defined with a local cut-off of CSF Aβ1-42 < 600 pg/mL; in patients with borderline Aβ1-42 values or when there was a mismatch between the Aβ and the T status (T + if CSF p-tau181 ≥ 65 pg/mL), a ratio Aβ1-42/Aβ1-40 < 0.07 was used. Plasma p-tau217 and p-tau181 were measured retrospectively, from blood samples collected at first visit, with Fujirebio Lumipulse and Quanterix Simoa assays, respectively. We included 468 patients (mean age 67 years, 50% female, 61% Aβ positive). Plasma p-tau217 outperformed plasma p-tau181 in discriminating CSF Aβ status (AUC 0.95 vs 0.90, p = 0.005). A 97.5% sensitivity and specificity plasma p-tau217 algorithm, classifying patients into three groups of Aβ probability (Low, Intermediate and High), resulted in 67% of patients in the Low and High groups, having their Aβ status predicted (as negative and positive, respectively) with 96% accuracy. The remaining 33% in the Intermediate group were candidates to undergo CSF/PET testing. A model with a 10% variation in p-tau217 levels yielded small changes in accuracy (95%). In conclusion, plasma p-tau217 could have discriminated CSF Aβ status in two-thirds of patients with very high accuracy in a memory clinic cohort. These results support the implementation of plasma p-tau217 as an initial diagnostic tool in memory clinics for AD diagnosis, reducing the need for more invasive/expensive testing.

Application of elastic net for clinical outcome prediction and classification in progressive supranuclear palsy: A multicenter cohort study

BACKGROUND

Previous studies have used machine learning to identify clinically relevant atrophic regions in progressive supranuclear palsy (PSP). This study applied Elastic Net (EN) in PSP to uncover key atrophic patterns, offering a novel approach to understanding its pathology.

METHODS

This study included baseline data from 74 patients with PSP enrolled in the Study of Comprehensive ANd multimodal marker-based cohort of PSP (SCAN-PSP, NCT05579301) in Seoul between January 2022 and August 2023. Participants were evaluated with PSP-rating scale (PSPRS) and Schwab & England Activity of daily living (SEADL). EN regression was used to identify regions with high explanatory power for clinical outcomes, which were combined with clinical parameters to build prediction models. Features selected from EN classification were applied to discriminate between the two groups.

RESULTS

EN identified the third ventricle, right anterior cingulate cortex, and left lateral orbitofrontal cortex as significant features, and multivariate linear regression models incorporating these regions with clinical variables showed high explainability for PSPRS (adjusted R2 = 0.62) and SEADL (adjusted R2 = 0.74). The EN-predicted values demonstrated strong correlation with actual scores of PSPRS (r = 0.75, p = 2·10-14) and SEADL (r = 0.82, p = 2·10-19). The combined EN-selected features and clinical parameters model robustly distinguished PSP-Richardson from the subcortical types (AUC = 0.94) and those with severe downgaze palsy from without (AUC = 0.90).

CONCLUSION

This study demonstrated that EN effectively identified significant regional atrophies in PSP, with a modest sample size. Future studies could incorporate multimodal analysis to identify markers for monitoring disease progression.

Long-read sequencing revealed complex biallelic pentanucleotide repeat expansions in RFC1-related Parkinson's disease

Biallelic intronic pentanucleotide repeat expansions, mainly (AAGGG)exp and/or (ACAGG)exp in RFC1, are detected in cerebellar ataxia, neuropathy and vestibular areflexia syndrome, late-onset ataxia, and in a wide disease spectrum including Charcot-Marie-Tooth disease, multiple system atrophy, and Parkinson's disease (PD). However, the genotype-phenotype correlation and underlying mechanism are mostly unknown. We screened RFC1-repeat expansions in 1445 patients with parkinsonism. Comprehensive genetic and clinical, and pathological assessments were performed. We report two early-onset patients with PD carrying complex biallelic pentanucleotide repeat expansions in RFC1. Long-read sequencing revealed a novel repeat configuration of (AGGGG)exp(AAGGG)14 and a possible somatic variant of (AAGGG)exp(AATGG)exp(AAGGG)exp in the (AAGGG)exp alleles in two RFC1-related PD patients. RNA foci were detected in the (AGGGG)exp-expressed HEK293T cell line as well as (AAGGG)exp and (ACAGG)exp, supporting (AGGGG)exp as a novel pathogenic repeat motif. This work revealed complex genotypes with novel repeat configuration of (AGGGG)exp and possible somatic (AATGG)exp insertion in RFC1-related PD.

Blood biomarker profiles in young-onset neurocognitive disorders: A cohort study

INTRODUCTION

Young-onset neurocognitive symptoms result from a heterogeneous group of neurological and psychiatric disorders which present a diagnostic challenge. To identify such factors, we analysed the Biomarkers in Younger-Onset Neurocognitive Disorders cohort, a study of individuals <65 years old presenting with neurocognitive symptoms for a diagnosis and who have undergone cognitive and biomarker analyses.

METHODS

Sixty-five participants (median age at assessment of 56 years, 45% female) were recruited during their index presentation to the Royal Melbourne Hospital Neuropsychiatry Centre, a tertiary specialist service in Melbourne, Australia, and categorized as either early-onset Alzheimer's disease (n = 18), non-Alzheimer's disease neurodegeneration (n = 23) or primary psychiatric disorders (n = 24). Levels of neurofilament light chain, glial fibrillary acidic protein and phosphorylated-tau 181, apolipoprotein E genotype and late-onset Alzheimer's disease polygenic risk scores were determined. Information-theoretic model selection identified discriminatory factors.

RESULTS

Neurofilament light chain, glial fibrillary acidic protein and phosphorylated-tau 181 levels were elevated in early-onset Alzheimer's disease compared with other diagnostic categories. A multi-omic model selection identified that a combination of cognitive and blood biomarkers, but not the polygenic risk score, discriminated between early-onset Alzheimer's disease and primary psychiatric disorders (area under the curve ⩾ 0.975, 95% confidence interval: 0.825-1.000). Phosphorylated-tau 181 alone significantly discriminated between early-onset Alzheimer's disease and non-Alzheimer's disease neurodegeneration causes (area under the curve = 0.950, 95% confidence interval: 0.877-1.00).

DISCUSSION

Discriminating between early-onset Alzheimer's disease, non-Alzheimer's disease neurodegeneration and primary psychiatric disorders causes of young-onset neurocognitive symptoms is possible by combining cognitive profiles with blood biomarkers. These results support utilizing blood biomarkers for the work-up of young-onset neurocognitive symptoms and highlight the need for the development of a young-onset Alzheimer's disease-specific polygenic risk score.

Performance of a Two-Week Rehabilitation Improves Motor Function in Inpatients with Progressive Supranuclear Palsy: A Pre-Post Study

Background: Progressive supranuclear palsy (PSP) is characterized by early postural instability and gait dysfunction, with frequent falls. Rehabilitation is an important therapeutic approach for motor dysfunction in patients with PSP. However, no conclusions have yet been drawn regarding the beneficial effects of rehabilitation in PSP, including the optimal duration of rehabilitation and differences in treatment effects among PSP subtypes. Herein, we investigated the effects of short-term rehabilitation and separately analyzed the effects on patients with PSP-Richardson's syndrome (RS) and PSP-progressive gait freezing (PGF). Methods: The participants underwent several therapeutic exercise programs individualized for each participant, performed over 2 weeks. Analysis was performed on 25 patients with PSP-RS and eight with PSP-PGF. Results: Short-term rehabilitation improved the Berg Balance Scale score in both the PSP-RS and PSP-PGF groups, step length on the symptom-dominant side in PSP-RS, the coefficient of variation of step length on the symptom-dominant side, and the stance phase of the Symmetry Index in PSP-PGF. Conclusions: Overall, this 2-week short-term rehabilitation intervention was shown to have beneficial effects on balance in patients with PSP-RS and PSP-PGF.

Biomarkers of disease progression in progressive supranuclear palsy for use in clinical trials

Progressive supranuclear palsy (PSP) is a rare neurodegenerative disease with no current disease-modifying treatments approved. Longitudinal research and clinical trials for PSP are ongoing and require reliable measures that are sensitive to disease progression. Despite susceptibility to subjective limitations, clinical and cognitive assessments are the most used instruments in therapeutic trials in PSP. The objective of this review was to identify measures that have been studied longitudinally as measures of progression and are suitable for use as clinical trial endpoints. We reviewed the measures currently used as trial endpoints, identifying the clinical, cognitive, fluid and imaging measures that have previously been studied longitudinally, and discuss current diagnostic and emerging measures that are yet to be studied longitudinally but that may be sensitive to disease progression. We found that many fluid and imaging measures require further research to validate their use as longitudinal measures of change, including emerging measures that have not yet been studied specifically in PSP. We also summarize the sample size estimates required to detect changes in a two-arm, 52-week therapeutic trial and found that specific MRI volumes require the smallest sample sizes to detect change.

Frequency of anti-IgLON5 disease in patients with a typical clinical presentation of progressive supranuclear palsy/corticobasal syndrome

Serum anti-IgLON5 antibodies, which were tested in 223 patients meeting the diagnostic criteria for progressive supranuclear palsy/corticobasal syndrome (PSP/CBS), were negative in all patients. Our study suggests that the frequency of anti-IgLON5 disease is extremely rare in patients with typical presentation of PSP/CBS.

An audit on the assessment and management of osteoporosis in a Parkinson's and related diseases clinic in Australia

BACKGROUND

Patients with Parkinson's disease (PD) and atypical parkinsonian syndromes are at increased risk of falls and should be actively screened and treated for osteoporosis. In 2024, the Royal Australian College of General Practitioners (RACGP) revised their practice guidelines for diagnosing and managing osteoporosis in postmenopausal women and men aged over 50 years.

OBJECTIVE

We conducted the first Australian study to audit these guidelines in patients with PD and atypical parkinsonian syndromes.

METHOD

We audited all PD, Dementia with Lewy Bodies, Progressive Supranuclear Palsy and Multiple System Atrophy cases attending our neurology service between January and March 2024 against the RACGP osteoporosis guidelines. We identified patients at risk of osteoporosis or minimal trauma fractures and assessed if they had been referred to their general practitioner (GP) for appropriate management or were already receiving appropriate osteoporosis treatment.

RESULTS

This audit evaluated 230 patients, 199 of which had PD. We identified 78 patients over the age of 50 years with risk factors that should trigger a GP bone health assessment as per the guidelines. Twenty-six of these patients were already being managed appropriately. However, only 12 of the remaining 52 'at risk' patients (23%) were directed to seek screening for osteoporosis by their GP, leaving 77% (40/52) without appropriate guidance.

CONCLUSION

Our major recommendations include following the guidelines and referring patients for a bone health screen with their GP if they have risk factors for osteoporosis. This audit highlighted that assessment of osteoporosis and fracture risk by Specialists needs to be improved.

Diagnostic value of six plasma biomarkers in progressive supranuclear palsy, multiple system atrophy, and Parkinson's disease

OBJECTIVES

This study aimed to evaluate the diagnostic ability of six plasma biomarkers in progressive supranuclear palsy (PSP), multiple system atrophy (MSA), and different subtypes of Parkinson's disease (PD).

METHODS

Neurofilament light chain (NfL), phosphorylated tau-181, glial fibrillary acidic protein (GFAP), amyloid-β 42 (Aβ42), and amyloid-β 40 (Aβ40) levels were measured using the single-molecule array (Simoa) technique in a cohort of patients with PSP, MSA, different subtypes of PD, and healthy controls (HCs).

RESULTS

Plasma NfL and GFAP levels were beneficial in discriminating between the disease groups and HCs. Plasma NfL, Aβ42, and Aβ40 could distinguish atypical Parkinsonian syndrome (APS) from PD and its subtypes. GFAP could discriminate APS from tremor dominant PD but could not discriminate APS from postural instability and gait disorder dominant PD. The efficacy of differentiation improved when a combination of multiple plasma biomarkers was applied.

CONCLUSIONS

In this study, the plasma biomarkers NfL, GFAP, Aβ42, and Aβ40 exhibited high discriminatory diagnostic value in PD and APS, and could be used as clinically potential diagnostic biomarkers. Plasma biomarker combinations could improve the differential diagnostic efficacy in the comparisons of PD and APS.

A smart tool for non expert clinicians for the dissemination of the MDS criteria for progressive supranuclear palsy

Due to the variety of clinical phenotypes and the massive clinical overlap with other neurodegenerative diseases, the diagnosis of Progressive Supranuclear Palsy (PSP) remains a major challenge. Notwithstanding, early and reliable clinical diagnosis of PSP is highly warranted for estimation of prognosis, appropriate allocation to therapeutic trials and development of new diagnostic tools. As reliable biomarkers are lacking, PSP diagnosis relies on the application of the clinical criteria promoted by the International Parkinson and Movement Disorder Society (MDS). Despite providing a framework including all the main PSP cornerstones (ocular dysfunction and postural instability, akinesia and cognitive dysfunction), the application of the MDS PSP criteria is complex and not straightforward to apply in a clinical setting. Herein we propose a practical tool, including a video-guided slide-set and a smartsheet, to disseminate the MDS PSP clinical criteria among healthy practitioners and increase confidence in non expert clinicians towards suspicion and diagnosis of PSP. The video-guided slide set may serve as a teaching resource for both general neurologists and practitioners, while the smartsheet may represent a valid support in attributing the degree of diagnostic certainty and phenotype based on the identified clinical features. Application of our tool may improve early recognition of patients in primary and secondary care and determine a prompt referral to third level movement disorder centers for consideration in clinical trials testing disease-modifying treatments.

Longitudinal assessment of white matter alterations in progressive supranuclear palsy variants using diffusion tractography

INTRODUCTION

White matter (WM) tract degeneration is a characteristic feature of progressive supranuclear palsy (PSP), with longitudinal changes observed in PSP-Richardson's syndrome (PSP-RS). Little, however, is known about the other PSP variants. We assessed cross-sectional and longitudinal WM degeneration across PSP variants using diffusion tractography.

METHODS

Forty-eight PSP patients were recruited by the Neurodegenerative Research Group, Mayo Clinic, and underwent two diffusion MRI, 1-year apart. We measured fractional anisotropy and mean diffusivity from eight WM tracts reconstructed using deterministic tractography. Baseline and rates of change were compared across PSP variants grouped into PSP-RS, PSP-cortical, and PSP-subcortical, and correlated with clinical disease severity.

RESULTS

PSP-RS, PSP-cortical and PSP-subcortical showed overlapping but distinct baseline patterns of WM alterations. Longitudinally, faster rates of degeneration were observed in the superior cerebellar peduncle (SCP) and dentatorubrothalamic tract (DRTT) in all groups compared to controls. In PSP-RS, the anterior thalamic radiation also showed faster rates of degeneration compared to controls. PSP-cortical had faster rates of degeneration in many WM tracts compared to controls and other PSP groups, including body of corpus callosum, superior thalamic radiation, superior corticostriatal tract, superior longitudinal fasciculus, and frontal aslant tract. Progression in the PSP-subcortical group was limited to SCP and DRTT. Greater rates of degeneration in the corpus callosum and SCP correlated with worsening disease severity.

CONCLUSIONS

Different progression patterns of WM degeneration characterize the PSP variants, although degeneration of the SCP is a common feature and could be a useful potential biomarker for clinical treatment trials in PSP.

Prospective Multicenter Evaluation of the MDS "Suggestive of PSP" Diagnostic Criteria

BACKGROUND

The recent Movement Disorders Society (MDS)-progressive supranuclear palsy (PSP) diagnostic criteria conceptualized three clinical diagnostic certainty levels: "suggestive of PSP" for sensitive early diagnosis based on subtle clinical signs, "possible PSP" balancing sensitivity and specificity, and "probable PSP" highly specific for PSP pathology.

OBJECTIVE

The aim of this study was to prospectively validate the criteria against long-term clinical follow-up and characterize the diagnostic certainty increase over time.

METHODS

Patients with "possible PSP" or "suggestive of PSP" diagnosis and clinical follow-up were recruited in two German multicenter longitudinal observational studies (ProPSP and DescribePSP). The cumulative percentage of patients longitudinally increasing diagnostic certainty was assessed over up to 2.5 years of follow-up. The sample size per arm required to detect 30% attenuated rate in diagnostic certainty increase in trials was estimated over multiple time intervals.

RESULTS

Of 254 patients with available longitudinal data, 61 patients had low diagnostic certainty at baseline (48 suggestive of PSP, 13 possible PSP) and multiple clinical visits (median: 3, range: 2-4). The cumulative percentage of patients increasing diagnostic certainty progressed with follow-up duration (30.4% at 6 months, 51.7% at 1 year, 80.4% at 2.5 years). The sample size required to detect 30% reduction in diagnostic certainty increase rate within 1 year was 163, slightly smaller than that required using the PSP rating scale.

CONCLUSIONS

Most "suggestive of PSP" patients increased diagnostic certainty upon longitudinal follow-up, providing the first prospective multicenter validation of MDS-PSP diagnostic criteria. Our data support the design of trials tailored for these early-stage patients, suggesting the PSP rating scale and the diagnostic certainty increase rate as potential endpoint measures. © 2025 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Idiopathic normal pressure hydrocephalus concomitant with progressive supranuclear palsy

INTRODUCTION

Recent studies by us and others have unveiled a frequent coexistence of idiopathic normal pressure hydrocephalus (iNPH) with neurodegenerative movement disorders, including progressive supranuclear palsy (PSP). This study aims to explore the clinical and radiological characteristics of patients with iNPH who also had comorbid with PSP, referred to as iNPHc + PSP.

METHODS

We retrospectively analyzed patients with iNPH admitted to our department between 2009 and 2024. We adhered to the established clinical criteria for iNPH and the Movement Disorder Society (MDS)-PSP criteria for probable or possible PSP with minor modifications.

RESULTS

Among 85 iNPH patients, 18 were categorized as having iNPHc + PSP (21.2 %). Clinically, comorbid PSP led to impaired vertical eye movement, axial-dominant parkinsonism, and a propensity to fall backward in iNPH (p = 0.022, p = 0.002, and p < 0.005, respectively). Radiologically, comorbid PSP demonstrated a shortened mesencephalic tegmentum length in the magnetic resonance imaging and an asymmetrical deficit of dopamine transporter activities in the DaTscan (p = 0.0005, p = 0.0129, respectively). Lumboperitoneal shunt (LPS) surgery improved the modified Rankin scale (p = 0.038) and the iNPH grading scale (total score, p = 0.003; gait disturbance, p = 0.020; urinary incontinence, p = 0.026) one-year after surgery.

CONCLUSIONS

PSP can coexist with iNPH, and detailed clinical and radiological assessment can aid in detecting this comorbidity. Importantly, LPS surgery can improve outcomes of patients with iNPHc + PSP.

Cognitive impairment in PSP compared with PD: assessment by clinical subtype and longitudinal change

Background

Longitudinal studies investigating cognitive function changes in patients with progressive supranuclear palsy (PSP) are limited. The variability of cognitive impairment across clinical subtypes of PSP remains unclear.

Objective

This study aimed to compare the longitudinal changes in cognitive function between patients with PSP and Parkinson's disease (PD) and to assess differences in cognitive impairment among PSP subtypes.

Methods

A retrospective observational study was conducted using neuropsychological testing data from patients with PSP and PD admitted to our hospital.

Results

The study included 38 patients with PD and 41 patients with PSP (23 PSP-Richardson's syndrome, 14 PSP-progressive gait freezing (PSP-PGF), 3 PSP-Parkinsonism and 1 PSP-predominant corticobasal syndrome). At baseline, cognitive function was significantly lower in the PSP group than in the PD group. Over 12 months, patients with PSP exhibited significant declines in multiple cognitive domains, whereas no significant changes were observed in the PD group. Among PSP subtypes, PSP-RS showed a faster rate of cognitive decline than PD, while PSP-PGF demonstrated a lower progression than PSP-RS.

Conclusion

PSP is associated with progressive cognitive impairment, with rates of decline varying by subtype. PSP-PGF exhibited a slower progression than PSP-RS. Clinical management should consider subtype-specific differences in cognitive prognosis to tailor treatment and care.

Screening properties of the updated normative framework for the Italian MMSE in MCI and dementia

BACKGROUND

This study aimed to assess the screening properties of Foderaro et al.s' updated normative framework for the Italian MMSE in detecting mild cognitive impairment (MCI) and dementia due to neurodegenerative, chronic cerebrovascular, and mixed etiologies, as well as in differentiating between these two syndromes.

METHODS

Data on 234 patients with either MCI (N = 83) or dementia (N = 151) due to Alzheimer's disease (N = 112), Lewy body disease (N = 11), frontotemporal lobar degeneration (N = 20), chronic cerebrovascular disease (N = 39), or mixed (N = 47) etiologies having been administered Foderaro et al.'s version of the MMSE were retrospectively recruited. Moreover, N = 247 healthy controls (HCs) with a normal Montreal Cognitive Assessment performance were prospectively recruited. Receiver-operating characteristics analyses were run to test the capability of both raw and demographically adjusted MMSE scores to discriminate both HCs from MCI/dementia and MCI from dementia. For these comparisons, screening metrics were also computed at Foderaro et al.'s cut-off (<26.02).

RESULTS

The capability of demographically adjusted MMSE scores to discriminate both HCs from dementia and MCI from dementia was excellent (AUC = 0.91 and 0.93, respectively), whilst good for MCI case-finding (AUC = 0.85). Consistently, the screening metrics associated with the cut-off at hand were optimal-to-excellent for dementia case-finding (sensitivity = 0.95; specificity = 0.99) and for the differentiation between MCI and dementia (sensitivity = 0.95; specificity = 0.64), whilst imbalanced for detecting MCI (sensitivity = 0.35; specificity = 0.99).

DISCUSSION

Foderaro et al.'s updated normative framework for the Italian MMSE has optimal screening properties for both dementia case-finding and the discrimination between MCI and dementia, being at variance unbalanced towards specificity when it comes to detecting MCI.

Plasma p-tau217 and neurofilament/p-tau217 ratio in differentiating Alzheimer's disease from syndromes associated with frontotemporal lobar degeneration

INTRODUCTION

Plasma-based biomarkers have shown promise for clinical implementation, but their accuracy in differentiating Alzheimer's disease (AD) from syndromes associated with frontotemporal lobar degeneration (FTLD) has yet to be fully investigated. This study assessed the potential of plasma biomarkers for differential diagnosis.

METHODS

This cohort study included 374 participants (96 AD, 278 FTLD). Plasma phosphorylated tau (p-tau)217, neurofilament light chain (NfL), brain-derived tau, glial fibrillary acidic protein, and the amyloid beta1-42/1-40 ratio were measured. Receiver operating characteristic curve analyses assessed diagnostic accuracy, and a three-range threshold approach was used to stratify patients based on the most accurate biomarker.

RESULTS

Plasma p-tau217 effectively distinguished AD from FTLD, with the NfL/p-tau217 ratio showing superior accuracy. The three-range approach identified thresholds with 95% and 97.5% sensitivity and specificity, reducing the need for cerebrospinal fluid testing by 75% and 54%, respectively.

DISCUSSION

Plasma p-tau217 and the NfL/p-tau217 ratio are promising non-invasive biomarkers for differentiating AD from FTLD, suggesting their use as a potential alternative to traditional diagnostic methods.

HIGHLIGHTS

Plasma phosphorylated tau (p-tau)217 distinguishes Alzheimer's disease (AD) from frontotemporal lobar degeneration (FTLD) with high accuracy. The neurofilament light chain/p-tau217 ratio showed the highest accuracy for differentiating AD from FTLD. A three-range threshold reduces the need for invasive cerebrospinal fluid testing or amyloid positron emission tomography imaging.

Cytoarchitectonic gradients of laminar degeneration in behavioural variant frontotemporal dementia

Behavioural variant frontotemporal dementia (bvFTD) is a clinical syndrome caused primarily by either tau (bvFTD-tau) or transactive response DNA-binding protein of 43 kDa (TDP-43) (bvFTD-TDP) proteinopathies. We previously found that lower cortical layers and dorsolateral regions accumulate greater tau than TDP-43 pathology; however, the patterns of laminar neurodegeneration across diverse cytoarchitecture in bvFTD are understudied. We hypothesized that bvFTD-tau and bvFTD-TDP have distinct laminar distributions of pyramidal neurodegeneration along cortical gradients, a topological order of cytoarchitectonic subregions based on increasing pyramidal density and laminar differentiation. Here, we tested this hypothesis in a frontal cortical gradient consisting of five cytoarchitectonic types (i.e. periallocortex, agranular mesocortex, dysgranular mesocortex, eulaminate-I isocortex and eulaminate-II isocortex) spanning the anterior cingulate, paracingulate, orbitofrontal and mid-frontal gyri in bvFTD-tau (n = 27), bvFTD-TDP (n = 47) and healthy controls (n = 32). We immunostained all tissue for total neurons (NeuN; neuronal-nuclear protein) and pyramidal neurons (SMI32; non-phosphorylated neurofilament) and digitally quantified NeuN-immunoreactivity (ir) and SMI32-ir in supragranular II-III, infragranular V-VI and all I-VI layers in each cytoarchitectonic type. We used linear mixed-effects models adjusted for demographic and biological variables to compare SMI32-ir between groups and examine relationships with the cortical gradient, long-range pathways and clinical symptoms. We found regional and laminar distributions of SMI32-ir expected for healthy controls, validating our measures within the cortical gradient framework. The SMI32-ir loss was relatively uniform along the cortical gradient in bvFTD-TDP, whereas SMI32-ir decreased progressively along the cortical gradient of bvFTD-tau and included greater SMI32-ir loss in supragranular eulaminate-II isocortex in bvFTD-tau versus bvFTD-TDP (P = 0.039). Using a ratio of SMI32-ir to model known long-range connectivity between infragranular mesocortex and supragranular isocortex, we found a larger laminar ratio in bvFTD-tau versus bvFTD-TDP (P = 0.019), suggesting that select long-projecting pathways might contribute to isocortical-predominant degeneration in bvFTD-tau. In cytoarchitectonic types with the highest NeuN-ir, we found lower SMI32-ir in bvFTD-tau versus bvFTD-TDP (P = 0.047), suggesting that pyramidal neurodegeneration might occur earlier in bvFTD-tau. Lastly, we found that reduced SMI32-ir was related to behavioural severity and frontal-mediated letter fluency, not temporal-mediated confrontation naming, demonstrating the clinical relevance and specificity of frontal pyramidal neurodegeneration to bvFTD-related symptoms. Our data suggest that loss of neurofilament-rich pyramidal neurons is a clinically relevant feature of bvFTD that worsens selectively along a frontal cortical gradient in bvFTD-tau, not bvFTD-TDP. Therefore, tau-mediated degeneration might preferentially involve pyramidal-rich layers that connect more distant cytoarchitectonic types. Moreover, the hierarchical arrangement of cytoarchitecture along cortical gradients might be an important neuroanatomical framework for identifying which types of cells and pathways are involved differentially between proteinopathies.

A 15-Item modification of the PSP rating scale to improve clinical meaningfulness and statistical performance

Progressive supranuclear palsy (PSP) is a rare neurodegenerative disorder characterized by physical, cognitive, and behavioral impairments. The PSP Rating Scale (PSPRS) is a widely used and validated, clinical scale to monitor disease progression. Here we show the modification of PSPRS to improve clinical meaningfulness and sensitivity. A conceptual framework was used to select meaningful items. Datasets were analyzed to improve the psychometric properties, understand factor structure, and develop a scoring algorithm. Fifteen items of the PSPRS were selected based on whether the items reflect concepts specific to the disease and those responsive to change over 12 months. Some items were rescored to reflect meaningful changes and to improve discrimination and reliability. The rescored 15-item PSPRS was more interpretable and sensitive to disease progression over 12 months. The approach to develop the 15-item PSPRS provides an example of how to modify an existing clinical outcome assessment for use as a primary endpoint in a clinical trial of a progressive neurological disorder.

Combined Assessment of Function and Survival to Demonstrate the Effect of Treatment on Progressive Supranuclear Palsy

BACKGROUND

Progressive supranuclear palsy (PSP) is a rare and fatal neurodegenerative disorder for which there are currently no disease-modifying treatments. Recent trials of potential therapies had durations of 12 months, which may be insufficient because of nonrandom missingness due to death. Longer durations, incorporating PSP Rating Scale and survival, can reduce the potential for type II error. Selecting efficacy measures more sensitive to disease modification may facilitate identification of treatment effect.

OBJECTIVE

The objective of this study was to evaluate the simulated phase 3 PSP trial assessing the effect of disease-modifying intervention on a novel combined primary endpoint comprising function (PSP Rating Scale) and survival, the Combined Assessment of Function and Survival (CAFS), and to determine operating characteristics of the CAFS.

METHODS

To simulate PSP progression in the trial population, we developed models of PSP Rating Scale and survival using data from published clinical studies. These models were used to define operating characteristics of the CAFS for use in a phase 3 trial.

RESULTS

The sample size determined (N = 384; 1:1 randomization) would provide >80% power to detect significant treatment effects on the CAFS compared with placebo. The CAFS provides good operating characteristics and increased power to detect moderate treatment effects on the PSP Rating Scale. We propose a trial design allowing potential detection of treatment effects at a preplanned interim analysis after participants complete 12 months of treatment, with assessment of effects of treatment (≤24 months) on survival.

CONCLUSIONS

Use of the CAFS could provide a comprehensive and robust estimate of the clinical benefit of future therapies. © 2024 UCB. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Assisted Parkinsonism Diagnosis Using Multimodal MRI-The Role of Clinical Insights

BACKGROUND

While automated methods for differential diagnosis of parkinsonian syndromes based on MRI imaging have been introduced, their implementation in clinical practice still underlies considerable challenges.

OBJECTIVE

To assess whether the performance of classifiers based on imaging derived biomarkers is improved with the addition of basic clinical information and to provide a practical solution to address the insecurity of classification results due to the uncertain clinical diagnosis they are based on.

METHODS

Retro- and prospectively collected data from multimodal MRI and standardized clinical datasets of 229 patients with PD (n = 167), PSP (n = 44), or MSA (n = 18) underwent multinomial classification in a benchmark study comparing the performance of nine machine learning methods. A predictor space of imaging variables, either with or without clinical information, was investigated. Classification results were assessed using multiclass AUCs. Individual predicted probabilities were visualized to address diagnostic uncertainty.

RESULTS

Clinical diagnosis was accurately confirmed using machine learning models with only small differences when using imaging and clinical signs versus imaging variables only (expected multiclass AUC of 0.95 vs. 0.92). Still, multinomial classification is hampered by imbalanced class frequencies. The most discriminatory variables were responsiveness to levodopa, vertical gaze palsy, and the volumes of subcortical structures, including the red nucleus.

CONCLUSION

Machine-learning-assisted classification of MR-imaging biomarkers gathered in routine care can assist in the diagnosis of parkinsonian syndromes as part of the diagnostic workup. We provide a visual method that aids the interpretation of neuroimaging-based classification results of the three main parkinsonian syndromes, improving clinical interpretability.

The Taiwan-ADNI workflow toward integrating plasma p-tau217 into prediction models for the risk of Alzheimer's disease and tau burden

INTRODUCTION

We integrated plasma biomarkers from the Taiwan Alzheimer's Disease Neuroimaging Initiative and propose a workflow to identify individuals showing amyloid-positive positron emission tomography (PET) with low/intermediate tau burden based on [18F]Florzolotau PET-based quantification.

METHODS

We assessed 361 participants across the Alzheimer's disease (AD) and non-AD continuum and measured plasma phosphorylated tau (p-tau)217, p-tau181, amyloid beta (Aβ)42/40 ratio, neurofilament light chain, and glial fibrillary acidic protein levels at two medical centers. We evaluated the diagnostic potential of these biomarkers.

RESULTS

Among all plasma biomarkers, p-tau217 had the highest consistency with amyloid PET results (area under the curve = 0.94), and a cutoff value could have reduced the number of confirmatory amyloid PET scans by 57.5%. In amyloid PET-positive cases intending to use anti-amyloid therapy, p-tau217 level, along with clinical parameters, had the highest predictive ability for low/intermediate tau burden.

DISCUSSION

A two-step workflow based on p-tau217 and confirmatory amyloid PET could accurately classify AD patients showing low/intermediate tau burden.

HIGHLIGHTS

The emergence of anti-amyloid therapy increases the need to accurately diagnose Alzheimer's disease (AD). The use of plasma biomarkers, especially phosphorylated tau 217 (p-tau217), can help in the diagnosis of AD. P-tau217 is a better predictor of amyloid positron emission tomography (PET) positivity than other core biomarkers. In amyloid PET-positive individuals, p-tau217 can predict tau burden. We propose a two-step workflow to identify AD cases suitable for treatment.

The Alzheimer's Association clinical practice guideline for the Diagnostic Evaluation, Testing, Counseling, and Disclosure of Suspected Alzheimer's Disease and Related Disorders (DETeCD-ADRD): Executive summary of recommendations for specialty care

US clinical practice guidelines for the diagnostic evaluation of cognitive impairment due to Alzheimer's disease (AD) or a related dementia (ADRD) are two decades old. This evidence-based guideline was developed to empower all clinicians to implement a structured approach for evaluating a patient with symptoms that may represent clinical AD/ADRD. An expert workgroup conducted a review of 7374 publications (133 met inclusion criteria) and developed recommendations as steps in an evaluation process. This summary briefly reviews core recommendations and details specialist recommendations of a high-quality, evidence-supported evaluation process aimed at characterizing, diagnosing, and disclosing the patient's cognitive functional status, cognitive-behavioral syndrome, and likely underlying brain disease so that optimal care plans to maximize patient/care partner dyad quality of life can be developed; a companion article summarizes primary care recommendations. If clinicians use the recommendations in this guideline and health-care systems provide adequate resources, outcomes should improve in most patients in most practice settings. HIGHLIGHTS: US clinical practice guidelines for the diagnostic evaluation of cognitive impairment due to Alzheimer's disease (AD) or related dementias (ADRD) are decades old and aimed at specialists. This evidence-based guideline was developed to empower all-including primary care-clinicians to implement a structured approach for evaluating a patient with symptoms that may represent clinical AD/ADRD. This summary focuses on recommendations appropriate for specialty practice settings, forming key elements of a high-quality, evidence-supported evaluation process aimed at characterizing, diagnosing, and disclosing the patient's cognitive functional status, cognitive-behavioral syndrome, and likely underlying brain disease so that optimal care plans to maximize patient/care partner dyad quality of life can be developed; a companion article summarizes primary care recommendations. If clinicians use this guideline and health-care systems provide adequate resources, outcomes should improve in most patients in most practice settings.

Recent progress in the applications of presynaptic dopaminergic positron emission tomography imaging in parkinsonism

Nowadays, presynaptic dopaminergic positron emission tomography, which assesses deficiencies in dopamine synthesis, storage, and transport, is widely utilized for early diagnosis and differential diagnosis of parkinsonism. This review provides a comprehensive summary of the latest developments in the application of presynaptic dopaminergic positron emission tomography imaging in disorders that manifest parkinsonism. We conducted a thorough literature search using reputable databases such as PubMed and Web of Science. Selection criteria involved identifying peer-reviewed articles published within the last 5 years, with emphasis on their relevance to clinical applications. The findings from these studies highlight that presynaptic dopaminergic positron emission tomography has demonstrated potential not only in diagnosing and differentiating various Parkinsonian conditions but also in assessing disease severity and predicting prognosis. Moreover, when employed in conjunction with other imaging modalities and advanced analytical methods, presynaptic dopaminergic positron emission tomography has been validated as a reliable in vivo biomarker. This validation extends to screening and exploring potential neuropathological mechanisms associated with dopaminergic depletion. In summary, the insights gained from interpreting these studies are crucial for enhancing the effectiveness of preclinical investigations and clinical trials, ultimately advancing toward the goals of neuroregeneration in parkinsonian disorders.

Upper motor neuron-predominant motor neuron disease presenting as atypical parkinsonism: A clinicopathological study

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by upper and lower motor neuron signs. There are, however, cases where upper motor neurons (UMNs) are predominantly affected, leading to clinical presentations of UMN-dominant ALS or primary lateral sclerosis. Furthermore, cases exhibiting an UMN-predominant pattern of motor neuron disease (MND) presenting with corticobasal syndrome (CBS) have been sparsely reported. This study aims to clarify the clinicopathological features of patients with UMN-predominant MND. We reviewed 24 patients with UMN-predominant MND with TDP-43 pathology in the presence or absence of frontotemporal lobar degeneration. Additionally, we reviewed the medical records of patients with pathologically-confirmed corticobasal degeneration (CBD) who received a final clinical diagnosis of CBS (n = 10) and patients with pathologically-confirmed progressive supranuclear palsy (PSP) who received a final clinical diagnosis of PSP syndrome (n = 10). Of 24 UMN-predominant MND patients, 20 had a clinical diagnosis of an atypical parkinsonian disorder, including CBS (n = 11) and PSP syndrome (n = 8). Only two patients had antemortem diagnoses of motor neuron disease. UMN-predominant MND patients with CBS less frequently exhibited apraxia than those with CBD, and they were less likely to meet clinical criteria for possible or probable CBS. Similarly, UMN-predominant MND patients with PSP syndrome less often met clinical criteria for probable PSP than PSP patients with PSP syndrome. Our findings suggest that UMN-predominant MND can mimic atypical parkinsonism, and should be considered in the differential diagnosis of CBS and PSP syndrome, in particular when criteria are not met.

A common marker of affect recognition dysfunction in the FTD spectrum of disorders

BACKGROUND

Poor affect recognition is an early sign of frontotemporal dementia (FTD). Here, we applied the abbreviated version of the Comprehensive Affect Testing System (CATS-A) battery to Italian FTD cases and healthy controls (HC) to provide cut-offs of emotional dysfunction in the whole group and in different FTD clinical syndromes.

METHODS

One hundred thirty-nine FTD patients (60 behavioural variant [bvFTD],13 semantic behavioural variant of FTD [sbvFTD], 28 progressive supranuclear palsy [PSP], 21 semantic [svPPA] and 17 nonfluent [nfvPPA] variants of primary progressive aphasia) and 116 HC were administered the CATS-A, yielding an Affective Recognition Quotient (ARQ), which was used as outcome measure. Age- and education-adjusted, regression-based norms were derived in HC. In patients, the ARQ was assessed for its internal reliability, factorial validity and construct validity by testing its association with another social cognition paradigm, the Story-Based Empath Task (SET). The diagnostic accuracy of the ARQ in discriminating patients from HC, genetic cases from HC and patient groups among each other was tested via ROC analyses.

RESULTS

In the whole FTD cohort, CATS-A proved to be underpinned by a mono-component factor (51.1%) and was internally consistent (McDonald's ω = 0.76). Moreover, the ARQ converged with the SET (r(122) = 0.50; p < 0.001) and optimally discriminated HC from both the whole cohort (AUC = 0.89) and each clinical syndrome (AUC range: 0.83-0.92). Conversely, CATS-A subtests were able to distinguish patient groups.

CONCLUSIONS

The ARQ score from the CATS-A distinguishes FTD clinical syndromes from HC with high accuracy, making it an excellent tool for immediate use in clinical practice.

Visual reading for [18F]Florzolotau Tau PET scans in progressive supranuclear palsy

PURPOSE

The identification of tau accumulation within living brains holds significant potential in facilitating accurate diagnosis of progressive supranuclear palsy (PSP). While visual assessment is frequently employed, standardized methods for tau positron emission tomography (PET) specifically in PSP are absent. We aimed to develop a visual reading algorithm dedicated to the evaluation of [18F]Florzolotau PET in PSP.

METHODS

148 PSP and 30 healthy volunteers were divided into a development set (for the establishment of the reading rules; n = 89) and a testing set (for the validation of the reading rules; n = 89). For differential diagnosis, 55 α-synucleinopathies were additionally included into the testing set. The visual reading method was established by an experienced assessor (Reader 0) and was then validated by Reader 0 and two additional readers on regional and overall binary manners. A positive binding in both midbrain and globus pallidus/putamen regions was characterized as a PSP-like pattern, whereas any other pattern was classified as non-PSP-like.

RESULTS

Reader 1 (94.4%) and Reader 2 (93.8%) showed excellent agreement for the overall binary determination against Reader 0. The regional binary determinations of midbrain and globus pallidus/putamen showed excellent agreement among readers (kappa > 0.80). The overall binary evaluation demonstrated reproducibility of 86.1%, 94.4% and 77.8% for three readers. The visual reading algorithm showed high agreement with regional standardized uptake value ratios and clinical diagnoses.

CONCLUSION

Through the application of the suggested visual reading algorithm, [18F]Florzorotau PET imaging demonstrated a robust performance for the imaging diagnosis of PSP.

Caregiver perspectives enable accurate diagnosis of neurodegenerative disease

BACKGROUND

The history from a relative or caregiver is an important tool for differentiating neurodegenerative disease. We characterized patterns of caregiver questionnaire responses, at diagnosis and follow-up, on the Cambridge Behavioural Inventory (CBI).

METHODS

Data-driven multivariate analysis (n = 4952 questionnaires) was undertaken for participants (n = 2481) with Alzheimer's disease (typical/amnestic n = 543, language n = 50, and posterior cortical n = 50 presentations), Parkinson's disease (n = 740), dementia with Lewy bodies (n = 55), multiple system atrophy (n = 55), progressive supranuclear palsy (n = 422), corticobasal syndrome (n = 176), behavioral variant frontotemporal dementia (n = 218), semantic (n = 125) and non-fluent variant progressive aphasia (n = 88), and motor neuron disease (n = 12).

RESULTS

Item-level support vector machine learning gave high diagnostic accuracy between diseases (area under the curve mean 0.83), despite transdiagnostic changes in memory, behavior, and everyday function. There was progression in CBI subscores over time, which varied by diagnosis.

DISCUSSION

Our results highlight the differential diagnostic information for a wide range of neurodegenerative diseases contained in a simple, structured collateral history.

HIGHLIGHTS

We analyzed 4952 questionnaires from caregivers of 2481 participants with neurodegenerative disease. Behavioral and neuropsychiatric manifestations of neurodegenerative disease had overlapping diagnostic boundaries. Simple questionnaire response patterns were sufficient for accurate diagnosis of each disease. We reinforce the value of a collateral history to support a diagnosis of dementia. The Cambridge Behavioural Inventory is sensitive to change over time and suitable as an outcome measure in clinical trials.

PET Imaging in Dementia: Mini-Review and Canadian Perspective for Clinical Use

PET imaging is increasingly recognized as an important diagnostic tool to investigate patients with cognitive disturbances of possible neurodegenerative origin. PET with 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG), assessing glucose metabolism, provides a measure of neurodegeneration and allows a precise differential diagnosis among the most common neurodegenerative diseases, such as Alzheimer's disease, frontotemporal dementia or dementia with Lewy bodies. PET tracers specific for the pathological deposits characteristic of different neurodegenerative processes, namely amyloid and tau deposits typical of Alzheimer's Disease, allow the visualization of these aggregates in vivo. [18F]FDG and amyloid PET imaging have reached a high level of clinical validity and are since 2022 investigations that can be offered to patients in standard clinical care in most of Canada.This article will briefly review and summarize the current knowledge on these diagnostic tools, their integration into diagnostic algorithms as well as perspectives for future developments.

Rapid Cognitive Deterioration in Progressive Supranuclear Palsy: A 1-Year Follow-Up Study

BACKGROUND

Nowadays, cognitive impairment has been characterized as one of the most vital clinical symptoms in progressive supranuclear palsy (PSP).

OBJECTIVES

Based on a relatively large cohort, we aimed to show the cognitive deterioration in different PSP subtypes during 1-year follow-up and investigate potential contributors for disease prognosis.

METHODS

One hundred seventeen patients from Progressive Supranuclear Palsy Neuroimage Initiative (PSPNI) cohort underwent neuropsychological tests and 1-year follow-up, with 73 diagnosed as PSP-Richardson syndrome (PSP-RS) and 44 as PSP-non-RS. Patients were divided into normal cognition (PSP-NC), mild cognitive impairment (PSP-MCI), and PSP-dementia. Cognitive impairment and progression rates were compared between PSP-RS and PSP-non-RS, and determinants for MCI conversion to dementia were calculated by multiple cox regression.

RESULTS

At baseline, 30.8% of PSP patients were diagnosed as dementia, 53.0% as MCI, and only 16.2% as NC. Compared to PSP-non-RS, PSP-RS suffered more from motor symptoms and cognitive impairment. During follow-up, PSP-RS also exhibited faster disease progression in Mini-Mental State Examination and visuospatial function, with cognitive deterioration in attention and executive function, but retained in language and memory subdomains. Twenty-seven of 62 PSP-MCI patients converted to dementia during follow-up, with the diagnosis of RS subtype as the most significant contributor to conversion (hazard ration = 2.993, 95% confidence interval = 1.451, 5.232, P = 0.009).

CONCLUSIONS

Patients with PSP-RS showed more severe cognitive impairment and faster decline longitudinally than patients with PSP-non-RS. Additionally, the diagnosis of RS subtype appears to be the most contributed factor for MCI conversion to dementia within just 1-year follow-up period.

Loss of Insight in Syndromes Associated with Frontotemporal Lobar Degeneration: Clinical and Imaging Features

OBJECTIVES

The present study aims to assess the prevalence, associated clinical symptoms, longitudinal changes, and imaging correlates of Loss of Insight (LOI), which is still unexplored in syndromes associated with Frontotemporal Lobar Degeneration (FTLD).

DESIGN

Retrospective longitudinal cohort study, from Oct 2009 to Feb 2023.

SETTING

Tertiary Frontotemporal Dementia research clinic.

PARTICIPANTS

A sample of 712 FTLD patients, 331 of whom had follow-up evaluation.

MEASUREMENTS

LOI was assessed by interview with the primary caregiver. Univariate and multiple logistic regression and linear mixed models were used to estimate predictors and longitudinal changes over time associated with LOI. Voxel-based morphometry and structural covariance analyses of brain structural MRI images were implemented in Statistical Parametric Mapping.

RESULTS

LOI was reported in 45% of patients (321/712, 95%CI = 41-49), with progressively increased prevalence from prodromal to severe dementia stages. LOI was more prevalent in the behavioural variant FTD, in the semantic variant of Primary Progressive Aphasia (svPPA) and FTD with Amyotrophic Lateral Sclerosis than in other phenotypes (all p-values<0.001). LOI severity increased over time only in patients with svPPA (β = +0.59, p <0.001) and clustered with other behavioral symptoms (all p-values <0.05). Finally, LOI was significantly associated with greater atrophy in the right medial orbital gyrus (p <0.001 uncorrected). Structural covariance analysis demonstrated loss of negative correlation between right medial orbital gyrus and regions belonging to the Default Mode Network (DMN), such as the left precuneus and the left angular gyrus (p ≤0.05 family-wise error-corrected) in FTLD patients with LOI.

CONCLUSIONS

A better comprehension of LOI mechanisms could lead to more effective interventions and healthcare policies.

Transdiagnostic Network Localization of Social, Language, and Motor Symptoms in Patients With Frontotemporal Lobar Degeneration

BACKGROUND AND OBJECTIVES

Frontotemporal lobar degeneration (FTLD) includes different clinical syndromes with distinct patterns of symptoms and neuroanatomical locations of neurodegeneration. However, FTLD is clinically heterogeneous (with overlapping symptoms across several domains) and neuroanatomically heterogeneous (with brain atrophy in different locations in different patients). Traditional methods struggle to fully account for this heterogeneity. In this study, we use a relatively new neuroimaging approach, atrophy network mapping, to localize clinical symptoms in patients with FTLD to specific brain networks transdiagnostically.

METHODS

Data were obtained from the Frontotemporal Lobar Degeneration Neuroimaging Initiative and 4-Repeat Tauopathy Neuroimaging Initiative. Inclusion required T1-weighted MRI and a diagnosis of behavioral-variant frontotemporal dementia (bvFTD), semantic-variant primary progressive aphasia (svPPA), nonfluent primary progressive aphasia (nfvPPA), progressive supranuclear palsy Richardson syndrome (PSP-rs), corticobasal syndrome (CBS), or normal cognition. Measures of social cognition (Interpersonal Reactivity Index, Revised Self-Monitoring Scale), language (Boston Naming Test, Animal Fluency), and motor function (Unified Parkinson Disease Rating Scale Part III, PSP Rating Scale) were correlated with neuroimaging measures, including cortical thickness, volume, and atrophy network mapping, a newer method that localizes regions connected to brain atrophy using a functional connectome from cognitively normal persons (n = 1,000).

RESULTS

Fifty-seven patients with bvFTD (age 61.2 ± 6.8 years, 35% female), 41 PSP-rs (age 69.7 ± 7.4 years, 54% female), 39 CBS (age 66.2 ± 6.2 years, 51% female), 37 svPPA (age 63.0 ± 6.0 years, 46% female), and 36 nfvPPA (age 68.3 ± 7.3 years, 53% female) and 135 healthy age-matched controls (age 63.3 ± 7.4 years, 58% female) were included. Compared with atrophy alone, atrophy network mapping showed more consistent neuroimaging results across patients with the same clinical syndrome (Dice index mean 0.68 vs 0.11, paired t = 263.1, df = 4,452, p < 0.001), more strongly explained social cognition (F(1, 84) = 10.2, p = 0.002) and motor symptoms (F(1, 185) = 91.3, p < 0.001) across different syndromes, and showed novel neuroanatomical associations, with the temporal parietal junction relating to social cognition; Wernicke area relating to language symptoms; and association sensorimotor cortex, thalamus, and cerebellum relating to motor symptoms.

DISCUSSION

Atrophy network mapping can improve understanding of brain-behavior relationships in clinically and neuroanatomically heterogeneous disorders such as FTLD.

Alzheimer's Association clinical practice guideline for the Diagnostic Evaluation, Testing, Counseling, and Disclosure of Suspected Alzheimer's Disease and Related Disorders (DETeCD-ADRD): Executive summary of recommendations for primary care

US clinical practice guidelines for the diagnostic evaluation of cognitive impairment due to Alzheimer's disease (AD) or AD and related dementias (ADRD) are decades old and aimed at specialists. This evidence-based guideline was developed to empower all-including primary care-clinicians to implement a structured approach for evaluating a patient with symptoms that may represent clinical AD/ADRD. Through a modified-Delphi approach and guideline-development process (7374 publications were reviewed; 133 met inclusion criteria) an expert workgroup developed recommendations as steps in a patient-centered evaluation process. This summary focuses on recommendations, appropriate for any practice setting, forming core elements of a high-quality, evidence-supported evaluation process aimed at characterizing, diagnosing, and disclosing the patient's cognitive functional status, cognitive-behavioral syndrome, and likely underlying brain disease so that optimal care plans to maximize patient/care partner dyad quality of life can be developed; a companion article summarizes specialist recommendations. If clinicians use this guideline and health-care systems provide adequate resources, outcomes should improve in most patients in most practice settings. Highlights US clinical practice guidelines for the diagnostic evaluation of cognitive impairment due to Alzheimer's disease (AD) or AD and related dementias (ADRD) are decades old and aimed at specialists. This evidence-based guideline was developed to empower all-including primary care-clinicians to implement a structured approach for evaluating a patient with symptoms that may represent clinical AD/ADRD. This summary focuses on recommendations, appropriate for any practice setting, forming core elements of a high-quality, evidence-supported evaluation process aimed at characterizing, diagnosing, and disclosing the patient's cognitive functional status, cognitive-behavioral syndrome, and likely underlying brain disease so that optimal care plans to maximize patient/care partner dyad quality of life can be developed; a companion article summarizes specialist recommendations. If clinicians use this guideline and health-care systems provide adequate resources, outcomes should improve in most patients in most practice settings.

Utility of Cerebrospinal Fluid Transferrin Receptor per Ferritin Ratio in Progressive Supranuclear Palsy

BACKGROUND

Progressive supranuclear palsy (PSP) is a major atypical parkinsonism. Because diagnosis based on the cardinal clinical features is often difficult, misdiagnosis with Parkinson's disease (PD) and multiple system atrophy (MSA) is common in PSP patients. Iron metabolism genes are reportedly involved in tau-accumulating neuronal cell death and ferroptosis in PSP, which is more severe than PD and MSA. The validity of transferrin receptor (TfR) expression as a biomarker of ferroptosis was also demonstrated.

OBJECTIVE

We investigated whether TfR and the TfR to ferritin ratio in the cerebrospinal fluid (CSF) is a diagnostic biomarker of PSP.

METHODS

This study included 2 independent retrospective CSF cohorts comprising patients, respectively, from Niigata University and a multicenter memory clinic, consisting of patients with PSP, PD, and MSA. All patients were classified as clinically probable or higher based on the Society of Movement Disorders Criteria. TfR and ferritin levels in the CSF were measured using Luminex assay.

RESULTS

The levels of TfR in patients with PSP were higher than those in patients with PD and MSA in cohort 1 (PSP: N = 16, PD: N = 13, MSA: N = 20). The TfR to ferritin ratio in patients with PSP was significantly higher than that in patients with MSA. Subsequently, we validated these results in cohort 2 (PSP: N = 23, MSA: N = 6). The TfR to ferritin ratio was significantly higher in patients with PSP than in those with MSA.

CONCLUSIONS

The CSF TfR to transferrin ratio was elevated in patients with PSP. These results should be validated in a larger cohort of patients.

Functional connectivity abnormalities in clinical variants of progressive supranuclear palsy

Progressive supranuclear palsy (PSP) can present with different clinical variants which show distinct, but partially overlapping, patterns of neurodegeneration and tau deposition in a network of regions including cerebellar dentate, superior cerebellar peduncle, midbrain, thalamus, basal ganglia, and frontal lobe. We sought to determine whether disruptions in functional connectivity within this PSP network measured using resting-state functional MRI (rs-fMRI) differed between PSP-Richardson's syndrome (PSP-RS) and the cortical and subcortical clinical variants of PSP. Structural MRI and rs-fMRI scans were collected for 36 PSP-RS, 25 PSP-cortical and 34 PSP-subcortical participants who met the Movement Disorder Society PSP clinical criteria. Ninety participants underwent flortaucipir-PET scans. MRIs were processed using CONN Toolbox. Functional connectivity between regions of the PSP network was compared between each PSP group and 83 healthy controls, and between the PSP groups, covarying for age. The effect of flortaucipir uptake and clinical scores on connectivity was assessed. Connectivity was reduced in PSP-RS compared to controls throughout the network, involving cerebellar dentate, midbrain, basal ganglia, thalamus, and frontal regions. Frontal regions showed reduced connectivity to other regions in the network in PSP-cortical, particularly the thalamus, caudate and substantia nigra. Disruptions in connectivity in PSP-subcortical were less pronounced, with the strongest disruption between the pallidum and striatum. There was moderate evidence that elevated subcortical flortaucipir uptake correlated with both increased and reduced connectivity between regions of the PSP network. Lower connectivity within the PSP network correlated with worse performance on clinical tests, including PSP rating scale. Patterns of disrupted functional connectivity revealed both variant-specific and shared disease pathways within the PSP network among PSP clinical variants, providing insight into disease heterogeneity.

Utility of Tau PET in the diagnostic work up of neurodegenerative dementia among Indian patients

BACKGROUND AND OBJECTIVES

Tau PET is being increasingly appraised as a novel diagnostic modality for dementia work up. Given limited data among South Asians, we assessed the frequency, patterns, phenotypic associations and incremental value of positive Tau PET scans in clinically diagnosed neurodegenerative dementia.

METHODS

This cross-sectional study recruited consecutive patients of Alzheimer's disease (AD) and non-AD syndromes (September 2021 to October 2022, India). Participants underwent clinical interview, cognitive assessment, MRI brain and tau PET scan ([F-18]ML-104). Visual read in a priori regions of interest was used to identify patterns of tau deposition in the brain.

RESULTS

We recruited 54 participants (mean age: 63.2 ± 9.2 years, 64.8 % men, 77.8 % dementia, 70.4 % early onset cases, 37.8 % APOE4+). The analysis identified abnormal tau uptake in 40/54 (74.1 %) participants; with uptake in AD signature areas in 27/40 (67.5 %) cases [cortical subtype (74.1 %), limbic (14.8 %), combined cortical/limbic (11.1 %)], and patterns not conforming to AD in 13/40 (32.5 %) cases. Tau PET substantiated the diagnosis of AD among 17/19 (89.5 %) cases with clinically diagnosed AD dementia, 8/23 (34.8 %) cases with suspected non-AD cause, and 2/12 (16.7 %) cases with mild cognitive impairment. A trend for increasing proportion of early onset cases, and worsening cognition, behavior and functional ability was seen, from 'limbic' to 'combined cortical/limbic' to 'cortical' subgroups.

CONCLUSION

Tau PET is a useful modality to differentiate AD dementia from other neurodegenerative causes in the Indian setting where amyloid biomarkers are not widely available. Biological subtypes of AD map well onto clinical phenotypes and need study in larger cohorts.

Diagnosing primary lateral sclerosis: a clinico-pathological study

BACKGROUND

 Primary lateral sclerosis (PLS) is a rare motor neuron disease characterized by upper motor neuron degeneration, diagnosed clinically due to the absence of a (neuropathological) gold standard. Post-mortem studies, particularly TDP-43 pathology analysis, are limited.

METHODS

This study reports on 5 cases in which the diagnostic criteria for PLS were met, but in which neuropathology findings showed (partially) conflicting results. These discrepancies prompted us to perform a clinico-pathology study focussing on diagnostic challenges and accuracy in PLS. To this end, all cases were reviewed by an international panel of 11 experts using an e-module and structured questionnaires.

RESULTS

Autopsy exhibited neuropathological findings consistent with amyotrophic lateral sclerosis (ALS) in one case, while two cases exhibited similar, but more limited lower motor neuron involvement, hinting at PLS or ALS overlap. Another case displayed tau-pathology indicative of progressive supranuclear palsy. The final case displayed extensive myelin loss without a proteinopathy or a clear diagnosis. The expert panel identified 24 different ancillary investigations lacking across cases (e.g. genetic testing, DAT scans, neuropsychological evaluation), listed 28 differential diagnoses, and identified 13 different conditions as the most likely diagnosis. Autopsy results led panel members to change their final diagnosis in 42% of the cases.

CONCLUSIONS

This study underscores the diagnostic challenges posed by diverse underlying pathologies resulting in upper motor neuron phenotypes. Despite adhering to the same diagnostic criteria, consensus amongst experts was limited. Ensuring the diagnostic consistency is crucial for advancing understanding and treatment of PLS. Explicit guidelines for excluding potential mimics along with a neuropathological gold standard are imperative.

Myelin basic protein and TREM2 quantification in the CSF of patients with Multiple System Atrophy and other Parkinsonian conditions

BACKGROUND

It is well known that myelin disruption and neuroinflammation are early and distinct pathological hallmarks in multiple system atrophy (MSA) as well as in idiopathic Parkinson's disease and in other atypical Parkinsonian syndromes. The objective of this study was to assess the value of non-neuronal biomarker candidates that reflect myelin disruption and neuroinflammation.

METHODS

Myelin basic protein (MBP) and the soluble form of TREM2 were quantified in a comprehensive movement disorder cohort from two different neurological centers, comprising a total of 171 CSF samples. Commercially available ELISA systems were employed for quantification.

RESULTS

The results of the MBP analysis revealed a significant increase in cerebrospinal fluid (CSF) MBP levels in all atypical Parkinsonian conditions compared to PD. This differentiation was more pronounced in the MSA-c subtype compared to MSA-p. Receiver operating characteristic (ROC) analysis revealed a significant discrimination between PD and MSA (p = 0.032, AUC = 0.70), PD and DLB (p = 0.006, AUC = 0.79) and PD and tauopathies (p = 0.006, AUC = 0.74). The results of the TREM2 analysis demonstrated no significant differences between the PD and atypical Parkinsonian groups if not adjusted for confounders. After adjusting for age, sex, and disease duration, the PD group exhibited significantly higher TREM2 levels compared to the DLB group (p = 0.002).

CONCLUSIONS

In conclusion, MBP, but not TREM2, is elevated in the CSF of not only MSA but in all atypical Parkinsonian conditions compared to idiopathic Parkinson's disease. This highlights the value of the evaluation of myelin/oligodendrocyte-associated markers in neurodegenerative movement disorders.