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

Possible Impact of Peripheral Inflammatory Factors and Interleukin-1β (IL-1β) on Cognitive Functioning in Progressive Supranuclear Palsy-Richardson Syndrome (PSP-RS) and Progressive Supranuclear Palsy-Predominant Parkinsonism (PSP-P)

Progressive supranuclear palsy (PSP) is a tauopathic atypical parkinsonian syndrome. Recent studies suggest that inflammation may play a role in PSP pathogenesis, highlighting markers like the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and cytokines such as IL-1β and IL-6. This study aimed to assess the relationship between peripheral inflammatory markers and psychological abnormalities in PSP-RS and PSP-P patients. The study included 24 participants: 12 with PSP-RS, 12 with PSP-P, and 12 controls. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA); however, the executive functions were evaluated using the Frontal Assessment Battery (FAB), while inflammatory markers such as IL-1β, IL6, NLR, and PLR were measured. The parameter correlation was executed using Spearman's correlation (rs). The analysis revealed significant negative correlations between NLR and MoCA (rs = -0.48), as well as between PLR and MoCA (rs = -0.60). The negative correlation between IL-1β and MoCA was statistically significant but relatively weak. This study highlights the relevance of inflammatory markers such as NLR and PLR in reflecting cognitive decline in PSP patients, with IL-1β potentially playing a protective role in cognitive function.

Atypical Parkinsonian Syndromes: Structural, Functional, and Molecular Imaging Features

Atypical parkinsonian syndromes, also known as Parkinson-plus syndromes, are a heterogeneous group of movement disorders, including dementia with Lewy bodies (DLB), progressive supranuclear palsy (PSP), multisystem atrophy (MSA), and corticobasal degeneration (CBD). This review highlights the characteristic structural, functional, and molecular imaging features of these complex disorders. DLB typically demonstrates parieto-occipital hypometabolism with involvement of the cuneus on FDG-PET, whereas dopaminergic imaging, such as [123I]-FP-CIT SPECT (DaTscan) or fluorodopa (FDOPA)-PET, can be utilized as an adjunct for diagnosis. PSP typically shows midbrain atrophy on structural imaging, whereas FDG-PET may be useful to depict frontal lobe hypometabolism and tau-PET confirms underlying tauopathy. MSA typically demonstrates putaminal or cerebellar atrophy, whereas FDG-PET highlights characteristic nigrostriatal or olivopontocerebellar hypometabolism, respectively. Finally, CBD typically shows asymmetric atrophy in the superior parietal lobules and corpus callosum, whereas FDG and tau-PET demonstrate asymmetric hemispheric and subcortical involvement contralateral to the side of clinical deficits. Additional advanced neuroimaging modalities and techniques described may assist in the diagnostic work-up or are promising areas of emerging research.

Serum Tau Species in Progressive Supranuclear Palsy: A Pilot Study

BACKGROUND/OBJECTIVES

Progressive Supranuclear Palsy (PSP) is a tauopathy showing a marked symptoms overlap with Parkinson's Disease (PD). PSP pathology suggests that tau protein might represent a valuable biomarker to distinguish between the two diseases. Here, we investigated the presence and diagnostic value of six different tau species (total tau, 4R-tau isoform, tau aggregates, p-tau202, p-tau231 and p-tau396) in serum from 13 PSP and 13 PD patients and 12 healthy controls (HCs).

METHODS

ELISA commercial kits were employed to assess all the tau species except for t-tau, which was assessed by a single molecule array (SIMOA)-based commercial kit. Possible correlations between tau species and biological and clinical features of our cohorts were also evaluated.

RESULTS

Among the six tau species tested, only p-tau396 was detectable in serum. Concentration of p-tau396 was significantly higher in both PSP and PD groups compared to HC, but PSP and PD patients showed largely overlapping values. Moreover, serum concentration of p-tau396 strongly correlated with disease severity in PSP and not in PD.

CONCLUSIONS

Overall, we identified serum p-tau396 as the most expressed phosphorylated tau species in serum and as a potential tool for assessing PSP clinical staging. Moreover, we demonstrated that other p-tau species may be present at too low concentrations in serum to be detected by ELISA, suggesting that future work should focus on other biological matrices.

Spatial discrimination in patients with MSA, PSP, DIP, and VP with pain

Pain is common in Parkinson's disease and frequently observed in other diseases involving parkinsonism. Abnormal scaling function in PD has been reportedly associated with pain, but the role of this function in pain in other parkinsonism-related diseases remains unknown. We screened 127 patients with multiple system atrophy (MSA, n = 24), progressive supranuclear palsy (PSP, n = 15), drug-induced parkinsonism (DIP, n = 56), or vascular parkinsonism (VP, n = 32). After screening, 79 patients with parkinsonism (23 MSA, 10 PSP, 28 DIP, and 18 VP patients) were included in the study. We divided the patients of each group into two groups (with or without pain).The percentages of patients in those groups with pain were 73.9%, 50.0%, 67.9%, and 66.7%, respectively. There was no difference in mean SDT between patients with and without pain in any disease (all p ≥ 0.052). The number of patients showing unmeasurable SDT did not differ between those with and without pain in any disease (all p ≥ 0.316). Our study found no evidence of a role of scaling function in pain development in parkinsonian disorders such as atypical parkinsonism, DIP, and VP.

Evaluation of Cerebrospinal Fluid α-Synuclein Seed Amplification Assay in Progressive Supranuclear Palsy and Corticobasal Syndrome

BACKGROUND

Seed amplification assay (SAA) testing has been developed as a biomarker for the diagnosis of α-synuclein-related neurodegenerative disorders.

OBJECTIVE

The objective of this study was to assess the rate of α-synuclein SAA positivity in progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS) and to analyze clinical and pathological features of SAA-positive and -negative cases.

METHODS

A total of 96 cerebrospinal fluid samples from clinically diagnosed PSP (n = 59) and CBS (n = 37) cases were analyzed using α-synuclein SAA.

RESULTS

Six of 59 (10.2%) PSP cases were α-synuclein SAA positive, including one case who was MSA-type positive. An exploratory analysis showed that PSP cases who were Parkinson's disease-type positive were older and had a shorter disease duration compared with SAA-negative cases. In contrast, 11 of 37 (29.7%) CBS cases were α-synuclein SAA positive, including two cases who were MSA-type positive.

CONCLUSIONS

Our results suggest that α-synuclein seeds can be detected in PSP and CBS using a cerebrospinal fluid α-synuclein SAA, and in PSP this may impact on clinical course.

Clinical and imaging correlates of hyperorality in syndromes associated with frontotemporal lobar degeneration

AIM

Empirical research investigating hyperorality in syndromes associated with frontotemporal lobar degeneration (FTLD) is limited. The present study aims to assess and describe hyperorality and its clinical and imaging correlates in patients with FTLD-associated syndromes.

METHODS

This retrospective longitudinal study included consecutive patients with FTLD who underwent a clinical, cognitive, and behavioral assessment. The presence and severity of hyperorality was assessed using the Frontal Behavior Inventory.

RESULTS

A total of 712 patients with FTLD were included in the study. Hyperorality was reported by 29% (204 of 712 [95% CI: 25-32%]) of patients; was more frequent in those with severe dementia than in those with prodromal or mild to moderate dementia (P < 0.05); was associated with younger age (odds ratio [OR] = 0.96 [95% CI: 0.94-0.99]), (P = 0.003) and positive family history for dementia (OR = 2.03 [95% CI: 1.18-3.49], P = 0.010); was overall more probable in the behavioral variant of frontotemporal dementia (bvFTD) and frontotemporal dementia with amyotrophic lateral sclerosis phenotypes, and less probable in other language or motor phenotypes; and was associated with higher severity of neuropsychiatric symptoms (OR = 1.08 [95% CI: 1.06-1.10], P < 0.001) and with the presence of several behavioral symptoms (P < 0.05). Moreover, hyperorality severity increased over time only in patients with bvFTD (β = +0.15, P = 0.011) or semantic variant of primary progressive aphasia (β = +0.34, P = 0.010). Finally, the presence of hyperorality was significantly associated with greater atrophy in the right anterior insula and right orbitofrontal region (false discovery rate-corrected P < 0.05).

CONCLUSION

Hyperorality is common in certain FTLD-associated syndromes. Understanding its correlates can help clinicians define pharmacological and educational interventions and clarify related anatomical circuits.

Multisite Skin Biopsies vs Cerebrospinal Fluid for Prion Seeding Activity in the Diagnosis of Prion Diseases

Importance

Recent studies have revealed that autopsy skin samples from cadavers with prion diseases (PRDs) exhibited a positive prion seeding activity similar to cerebrospinal fluid (CSF). It is worthwhile to validate the findings with a large number of biopsy skin samples and compare the clinical value of prion seeding activity between skin biopsies and concurrent CSF specimens.

Objective

To compare the prion seeding activity of skin biopsies and CSF samples and to determine the effectiveness of combination of the skin biopsies from multiple sites and numerous dilutions on the diagnosis for various types of PRDs.

Design, Setting, and Participants

In the exploratory cohort, patients were enrolled from September 15, 2021, to December 15, 2023, and were followed up every 3 months until April 2024. The confirmatory cohort enrolled patients from December 16, 2023, to June 31, 2024. The exploratory cohort was conducted at a single center, the neurology department at Xuanwu Hospital. The confirmatory cohort was a multicenter study involving 4 hospitals in China. Participants included those diagnosed with probable sporadic Creutzfeldt-Jakob disease or genetically confirmed PRDs. Patients with uncertain diagnoses or those lost to follow-up were excluded. All patients with PRDs underwent skin sampling at 3 sites (the near-ear area, upper arm, lower back, and inner thigh), and a portion of them had CSF samples taken simultaneously. In the confirmatory cohort, a single skin biopsy site and CSF samples were simultaneously collected from a portion of patients with PRDs.

Exposures

The skin and CSF prion seeding activity was assessed using the real-time quaking-induced conversion (RT-QUIC) assay, with rHaPrP90-231, a Syrian hamster recombinant prion protein, as the substrate. In the exploratory cohort, skin samples were tested at dilutions of 10-2 through 10-4. In the confirmatory cohort, skin samples were tested at a dilution of 10-2. A total of four 15-μL wells of CSF were used in the RT-QUIC assay.

Main Outcomes and Measures

Correlations between RT-QUIC results from the skin and CSF and the final diagnosis of enrolled patients.

Results

In the exploratory cohort, the study included 101 patients (mean [SD] age, 60.9 [10.2] years; 63 female [62.4%]) with PRD and 23 patients (mean [SD] age, 63.4 [9.1] years; 13 female [56.5%]) without PRD. A total of 94 patients had CSF samples taken simultaneously with the skin biopsy samples. In the confirmatory cohort, a single skin biopsy site and CSF sample were taken simultaneously in 43 patients with PRDs. Using an experimental condition of 10-2 dilution, the RT-QUIC positive rates of skin samples from different sites were comparable with those of the CSF (skin: 18 of 26 [69.2%] to 74 of 93 [79.6%] vs CSF: 71 of 94 [75.5%]). When tested at 3 different dilutions, all skin sample positivity rates increased to over 80.0% (79 of 93 for the near-ear area, 21 of 26 for the upper arm, 77 of 92 for the lower back, and 78 of 92 for the inner thigh). Combining samples from skin sites near the ear, inner thigh, and lower back in pairs yielded positivity rates exceeding 92.1% (93 of 101), significantly higher than CSF alone (71 of 94 [75.5%]; P =.002). When all skin sample sites were combined and tested at 3 dilution concentrations for RT-QUIC, the sensitivity reached 95.0% (96 of 101). In the confirmatory cohort, the RT-QUIC positive rate of a single skin biopsy sample was slightly higher than that of the CSF (34 of 43 [79.1%] vs 31 of 43 [72.1%]; P = .45).

Conclusions and Relevance

Results of this diagnostic study suggest that the sensitivity of an RT-QUIC analysis of a combination of 2 or more skin sites was superior to that of CSF in diagnosing PRDs.

A General Neurologist's Practical Diagnostic Algorithm for Atypical Parkinsonian Disorders: A Consensus Statement

Purpose of Review

The most common four neurodegenerative atypical parkinsonian disorders (APDs) are progressive supranuclear palsy (PSP), multiple system atrophy (MSA), corticobasal syndrome (CBS), and dementia with Lewy bodies (DLB). Their formal diagnostic criteria often require subspecialty experience to implement as designed and all require excluding competing diagnoses without clearly specifying how to do that. Validated diagnostic criteria are not available at all for many of the other common APDs, including normal pressure hydrocephalus (NPH), vascular parkinsonism (VP), or drug-induced parkinsonism (DIP). APDs also include conditions of structural, genetic, vascular, toxic/metabolic, infectious, and autoimmune origin. Their differential diagnosis can be challenging early in the course, if the presentation is atypical, or if a rare or non-neurodegenerative condition is present. This review equips community general neurologists to make an early provisional diagnosis before, or in place of, referral to a tertiary center. Early diagnosis would allay diagnostic uncertainty, allow prompt symptomatic management, provide disease-specific information and support resources, avoid further pointless testing and treatments, and create the possibility of trial referral.

Recent Findings

We address 64 APDs using one over-arching flow diagram and a series of detailed tables. Most instances of APDs can be diagnosed with a careful history and neurological exam, along with a non-contrast brain MRI. Additional diagnostic tests are rarely needed but are delineated where applicable. Our diagnostic algorithm encourages referral to a tertiary center whenever the general neurologist feels it would be in the patient's best interest. Our algorithm emphasizes that the diagnosis of APDs is an iterative process, refined with the appearance of new diagnostic features, availability of new technology, and advances in scientific understanding of the disorders. Clinicians' proposals for all diagnostic tests for the APDs, including repeat visits, should be discussed with patients and their families to ensure that the potential information to be gained aligns with their larger clinical goals.

Summary

We designed this differential diagnostic algorithm for the APDs to enhance general neurologists' diagnostic skills and confidence and to help them address the less common or more ambiguous cases.

Distinct Cognitive Trajectories According to Amyloid Positivity in Non-Alzheimer Disease Dementias

BACKGROUND

The clinical effects of β-amyloid positivity (Aβ+) on copathologies in various dementias remain relatively underexamined. Thus, the present study was conducted to investigate the prevalence and clinical effects of Aβ+ in subcortical vascular cognitive impairment (SVCI) and frontotemporal dementia (FTD).

PATIENTS AND METHODS

We enrolled SVCI (n = 583), FTD (n = 152), and cognitively unimpaired (CU) participants (n = 1,249) who underwent Aβ PET scans. The odds of having Aβ+ were subsequently compared among the diagnostic groups (CU, SVCI, and FTD) according to age and apolipoprotein E genotype. Additionally, a linear mixed-effects model was used to investigate the effects of Aβ+ on cognitive trajectories in SVCI and FTD.

RESULTS

Compared with CU, the SVCI group had a higher prevalence of Aβ+ in the 75 to 90 years age group (adjusted odds ratio, 1.97; 95% confidence interval, 1.36-2.85; P < 0.001), as well as within the apolipoprotein E ε3/ε3 group (adjusted odds ratio, 1.78; 95% confidence interval, 1.20-2.63; P = 0.001), whereas the FTD group showed no difference in Aβ+ prevalence. Aβ+ was associated with a worse cognitive trajectory in SVCI (adjusted β-coefficient = -0.6424; P < 0.001), but not in FTD.

CONCLUSIONS

These findings contribute to our understanding of Aβ biomarker traits in various dementias in Korea.

Flanagan's condensed protocol for neurodegenerative diseases. Implementation in a clinical autopsy setting with partial supervision of a neuropathologist

The Condensed Protocol (CP) was originally developed for the evaluation of Alzheimer's Disease (AD) and other neurodegenerative diseases as a workable alternative to the complex and costly established autopsy guidelines. The study objective is to examine the degree of implementation of the CP in the pathology department of a third level university hospital in a period of 5 years. Clinical autopsies performed between 2016 and 2021 on patients aged 65 years or over and did not require a specific neuropathological examination were reviewed. Histological screening and staging of neurodegenerative diseases was performed using the original immunohistochemical stains. Out of 255 autopsies, 204 met the inclusion criteria and 190 could be reviewed. The CP was applied to 99 cases; histological signs of neurodegenerative disease were observed in 92. Sampling errors were detected in 59 cases. Immunohistochemical studies were performed in 68 cases. The diseases identified were: 31 cases of AD (12 low grade; 19 intermediate), 18 amyloid angiopathy, 15 primary age-related tauopathy, 6 argyrophilic grain disease, 3 progressive supranuclear palsy, 1 Lewy body disease (of 22 cases), and 2 limbic-predominant age TDP43 encephalopathy (of 5 cases). In 30 out of 83 cases, there was more severe vascular pathology in complete sections of frontal cortex and lentiform nucleus. The CP allows reliable detection and staging of AD and related neurodegenerative diseases in clinical autopsies. However, supervision by a neuropathologist seems necessary for a fully successful implementation of the CP in a clinical hospital setting.

Quantitative Comparisons of Progressive Supranuclear Palsy Rating Scale Versions Using Item Response Theory

BACKGROUND

Progressive supranuclear palsy (PSP) is a neurodegenerative, late-onset disease that is challenging in terms of assessment. The Progressive Supranuclear Palsy Rating Scale (PSPRS), a 28-item clinician-reported scale, is the most established clinical outcome assessment method. Recently, the U.S. Food and Drug Administration (FDA) has proposed a subscale of 10 items as an alternative to full PSPRS.

OBJECTIVES

To quantitatively evaluate and compare the properties of full PSPRS and the FDA subscale using item response theory. To develop a progression model of the disease and assess relative merits of study designs and analysis options.

METHODS

Data of 979 patients from four interventional trials and two registries were available for analysis. Our investigation was divided into: (1) estimating informativeness of the 28 items; (2) estimating disease progression; and (3) comparing the scales, trial designs, and analysis options with respect to power to detect a clinically relevant treatment effect.

RESULTS

PSPRS item scores had a low pairwise correlation (r = 0.17 ± 0.14) and the items irritability, sleep difficulty, and postural tremor were uncorrelated with the other items. The FDA-selected items displayed higher correlation (r = 0.35 ± 0.14) and were the basis for a longitudinal item response model including disease progression. Trial simulations indicated that identification of a disease-modifying treatment effect required less than half the study size if the analysis was based on longitudinal item information compared with total scores at end-of-treatment.

CONCLUSION

A longitudinal item response model based on the FDA-selected PSPRS items is a promising tool in evaluating treatments for PSP. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Immunometabolic Signature and Tauopathy Markers in Blood Cells of Progressive Supranuclear Palsy

BACKGROUND

Peripheral immune cells critically contribute to the clinical-pathological progression of neurodegenerative diseases and also represent a reliable frame for translational applications. However, data on progressive supranuclear palsy (PSP) are almost scarce in this regard.

OBJECTIVE

Our goal is to provide a broad biological characterization of peripheral immune cells in a selected PSP cohort.

METHODS

Seventy-one PSP patients scored on the PSP Rating Scale (PSPRS), and 59 controls were enrolled. The blood cell count was collected, together with the neutrophil-to-lymphocyte ratio (NLR) calculation. In a subgroup of patients and controls, the peripheral blood mononuclear cells (PBMCs) were analyzed by the mitochondrial bioenergetic performance and the western blot assay of the nuclear factor erythroid 2-related factor (NRF2)/heme oxygenase 1 (HO-1) pathway and the total tau (t-tau) and phosphorylated tau (p-tau) proteins. Case-control comparison and correlation analyses were performed.

RESULTS

PSP patients had a NLR higher than controls, with increased circulating neutrophils. The leukocyte metabolism was also globally increased and the NRF2/HO-1 pathway activated in patients. P-tau, but not t-tau, significantly accumulated in PSP PBMCs and inversely correlated with the PSPRS.

CONCLUSIONS

PSP displays a systemic inflammatory shift of the peripheral immunity, which may justify a metabolic reprogramming of the blood leukocytes. Consistently, the NRF2/HO-1 pathway, a master regulator of inflammatory and metabolic response, was activated. PBMCs also engulf tau proteins, especially p-tau, in a way inverse to the disease severity, allowing for a peripheral tracking of tauopathy in patients. Immunometabolic targets may, therefore, gain relevance to PSP in biomarker or therapeutic purposes. © 2024 International Parkinson and Movement Disorder Society.

Peripheral immune profile and neutrophil-to-lymphocyte ratio in progressive supranuclear palsy: Case-control study and meta-analysis

BACKGROUND AND PURPOSE

Peripheral inflammation is probably involved in the pathogenesis of progressive supranuclear palsy (PSP) and it may be a common feature with Parkinson's disease (PD). The peripheral immune profile in PSP remains unclear, as well as whether the inflammatory pathways differ from those in PD. The neutrophil-to-lymphocyte ratio (NLR) has been proven to be a well-established biomarker of systemic inflammation. This study aimed to evaluate the peripheral immune profile in PSP compared with PD.

METHODS

A cross-sectional study was conducted including patients with PSP and PD and healthy controls (HCs). Leukocyte subpopulations and the NLR were measured in peripheral blood. Multivariate linear regression and post hoc tests were applied. Electronic databases were searched in November 2023 to perform meta-analyses to clarify the peripheral immune profile in PSP.

RESULTS

Our cohort included 121 patients with PSP, 127 patients with PD and 266 HCs. The NLR was higher in PSP and PD compared with HCs. PSP had a higher neutrophil count compared with HCs. Whilst a lower lymphocyte count was found in PD compared with HCs, the lymphocyte count did not differ between PSP and HCs. The meta-analyses supported this immune profile.

CONCLUSIONS

PSP and PD show an increased peripheral inflammation and a higher NLR compared with HCs. Different pathogenic inflammatory mechanisms are probably involved in PSP and PD, since in PSP this altered peripheral immune profile is mainly driven by neutrophils. Understanding the neutrophils' role in PSP may allow for the development of targeted therapies.

The Effect of Alcohol Consumption on Progressive Supranuclear Palsy: A Cross-Sectional Study

AIMS

To investigate the effect of alcohol consumption on the clinical symptoms in a cohort of Progressive supranuclear palsy (PSP) patients.

METHODS

We conducted a cross-sectional study focusing on possible and probable PSP patients in Qilu Hospital of Shandong University. Diagnoses and clinical phenotypes were confirmed using the 2017 Movement Disorder Society criteria and the Multiple Allocations eXtinction (MAX) rules. Data on drinking habits and demographics were collected via face-to-face interviews and medical records reviews. Clinical scales assessed motor and nonmotor symptoms. Alcohol consumption was categorized into light, moderate, and heavy status. Using multivariate linear regression and adjusting for confounding factors, we analyzed the relationship between alcohol consumption and clinical symptoms.

RESULTS

The study comprised 128 participants (59.4% male and 45.31% drinkers). Alcohol consumption has been associated with severe PSP clinical symptoms, particularly among male patients. Compared with nondrinkers, consumers of alcohol exhibit significantly more severe motor symptoms and cognitive impairments, particularly in the domains of visuospatial and executive abilities, memory, and language. Moreover, when categorizing individuals based on their intake of alcohol weekly, those with heavy consumption show significantly higher PSP Rating Scale (PSPRS) and the Unified Parkinson's Disease Rating Scale (UPDRS) scores, as well as significantly lower Montreal Cognitive Assessment Scale (MoCA) and Mini Mental State Examination (MMSE) scores compared to nonconsumers.

CONCLUSION

Our findings indicate an association between heavy alcohol consumption and more pronounced symptoms of PSP, especially cognitive function. It raises the possibility that alcohol intake may play a role in modulating the clinical course of PSP.

Lexical markers of disordered speech in primary progressive aphasia and 'Parkinson-plus' disorders

Connected speech samples elicited by a picture description task are widely used in the assessment of aphasias, but it is not clear what their interpretation should focus on. Although such samples are easy to collect, analyses of them tend to be time-consuming, inconsistently conducted and impractical for non-specialist settings. Here, we analysed connected speech samples from patients with the three variants of primary progressive aphasia (semantic, svPPA N = 9; logopenic, lvPPA N = 9; and non-fluent, nfvPPA N = 9), progressive supranuclear palsy (PSP Richardson's syndrome N = 10), corticobasal syndrome (CBS N = 13) and age-matched healthy controls (N = 24). There were three principal aims: (i) to determine the differences in quantitative language output and psycholinguistic properties of words produced by patients and controls, (ii) to identify the neural correlates of connected speech measures and (iii) to develop a simple clinical measurement tool. Using data-driven methods, we optimized a 15-word checklist for use with the Boston Diagnostic Aphasia Examination 'cookie theft' and Mini Linguistic State Examination 'beach scene' pictures and tested the predictive validity of outputs from least absolute shrinkage and selection operator (LASSO) models using an independent clinical sample from a second site. The total language output was significantly reduced in patients with nfvPPA, PSP and CBS relative to those with svPPA and controls. The speech of patients with lvPPA and svPPA contained a disproportionately greater number of words of both high frequency and high semantic diversity. Results from our exploratory voxel-based morphometry analyses across the whole group revealed correlations between grey matter volume in (i) bilateral frontal lobes with overall language output, (ii) the left frontal and superior temporal regions with speech complexity, (iii) bilateral frontotemporal regions with phonology and (iv) bilateral cingulate and subcortical regions with age of acquisition. With the 15-word checklists, the LASSO models showed excellent accuracy for within-sample k-fold classification (over 93%) and out-of-sample validation (over 90%) between patients and controls. Between the motor disorders (nfvPPA, PSP and CBS) and lexico-semantic groups (svPPA and lvPPA), the LASSO models showed excellent accuracy for within-sample k-fold classification (88-92%) and moderately good (59-74%) differentiation for out-of-sample validation. In conclusion, we propose that a simple 15-word checklist provides a suitable screening test to identify people with progressive aphasia, while further specialist assessment is needed to differentiate accurately some groups (e.g. svPPA versus lvPPA and PSP versus nfvPPA).

Neuronal and oligodendroglial, but not astroglial, tau translates to in vivo tau PET signals in individuals with primary tauopathies

Tau PET has attracted increasing interest as an imaging biomarker for 4-repeat (4R)-tauopathy progressive supranuclear palsy (PSP). However, the translation of in vitro 4R-tau binding to in vivo tau PET signals is still unclear. Therefore, we performed a translational study using a broad spectrum of advanced methodologies to investigate the sources of [18F]PI-2620 tau PET signals in individuals with 4R-tauopathies, including a pilot PET autopsy study in patients. First, we conducted a longitudinal [18F]PI-2620 PET/MRI study in a 4-repeat-tau mouse model (PS19) and detected elevated [18F]PI-2620 PET signals in the presence of high levels of neuronal tau. An innovative approach involving cell sorting after radiotracer injection in vivo revealed higher tracer uptake in single neurons than in the astrocytes of PS19 mice. Regional [18F]PI-2620 tau PET signals during the lifetime correlated with the abundance of fibrillary tau and with autoradiography signal intensity in PSP patients and disease controls who underwent autopsy 2-63 months after tau PET. In autoradiography, tau-positive neurons and oligodendrocytes with a high AT8 density, but not tau-positive astrocytes, were the drivers of [18F]PI-2620 autoradiography signals in individuals with PSP. The high tau abundance in oligodendrocytes at the boundary of gray and white matter facilitated the identification of an optimized frontal lobe target region to detect the tau burden in patients with PSP. In summary, neuronal and oligodendroglial tau constitutes the dominant source of tau PET radiotracer binding in 4-repeat-tauopathies, translating to an in vivo signal.

Psychometric properties and clinical correlates of the Frontal Behaviour Inventory in progressive supranuclear palsy: data from the PSP-NET

OBJECTIVES

Neuropsychiatric symptoms, such as apathy, disinhibition and irritability, are common in Progressive Supranuclear Palsy (PSP). The Frontal Behaviour Inventory (FBI) is a useful instrument for the evaluation of behavioural disorders in neurodegenerative diseases. The main goal of the present study was to explore the psychometric properties of the FBI in PSP.

DESIGN, SETTING AND PARTICIPANTS

FBI was administered to the PSP-NET cohort including Italian patients diagnosed according to the Movement Disorder Society criteria. Patients underwent a clinical interview, a motor evaluation, extensive cognitive and behavioural testing.

RESULTS

Two hundred and eight subjects were included in this study. The internal consistency was high (Cronbach's alpha = 0.868) and no improvement of this value was noted upon removal of any item. FBI showed also good acceptability, reliability and validity. The standard error of measurement (SEM) value for FBI total score was 0.169 [SEM = SD √ (1 - Cronbach's alpha)]. Factor analysis indicated a five-factor structure: Apathy, Behavioural disorders, Impulsivity, Motor and speech frontal behaviour and Executive disorders that explained the 54.92% of the total variance. Linear regression analysis showed that global cognitive impairment significantly affects both Apathy and Motor and speech frontal behaviour factors.

CONCLUSIONS

In conclusion, FBI is a reliable and valid tool for the assessment of neuropsychiatric symptoms in PSP, despite some constructs, such as euphoria and irritability, are better measured by the NPI. Two third of the cohort was represented by Richardson's syndrome, thus our data are mainly applicable to such common phenotype. Such data are useful in both clinical and research settings to plan adequate therapeutic interventions and to improve the quality of life of PSP patients and their caregivers.

Quality of life in patients with progressive supranuclear palsy: a review of literature and implications for practice

Progressive supranuclear palsy (PSP) is an atypical form of parkinsonism characterized by tauopathy, manifesting as oculomotor dysfunction, postural instability, akinesia, and cognitive/language impairments. The diagnosis and examination of PSP can be challenging, primarily due to the unclear and underexplored pathomechanisms involved, alongside absence of effective treatments. Clinical variants of PSP is the second most common form of neurodegenerative parkinsonism after Parkinson's disease (PD). It is defined by a symmetrical akinetic-rigid syndrome (atypical parkinsonism) and vertical supranuclear gaze palsy. In contrast to PD, PSP often presents with gait instability, backward falls, and cognitive and behavioral changes at early disease stages. The classification of PSP has evolved since Richardson, Steele, and Olszewski's initial reporting of the condition in 1963, which included a cohort of nine patients. Over the years, the definition of this disorder has evolved to encapsulate a group of patients with distinct clinical variants, notably the classical Richardson syndrome (RS) and several atypical phenotypes, each with significant implications for disease progression and quality of life (QoL). The 2017 Movement Disorder Society Diagnostic Criteria by Hoglinger et al., improved the sensitivity for detecting early and variant PSP presentations and provided more specific differential diagnoses for conditions such as PD and other forms of atypical parkinsonian syndromes. Owing to the growing interest in the disease's progression, evaluating the QoL for patients with PSP has become crucial. This review emphasizes the significance of QoL evaluation and its feasibility for practical implications, serving as an initial foundation for future research focused on the well-being of individuals affected by PSP. Progressive supranuclear palsy (PSP) is an atypical form of parkinsonism characterized by tauopathy, manifesting as oculomotor dysfunction, postural instability, akinesia, and cognitive/language impairments. Diagnosing PSP is challenging owing to the lack of tools for differential examination. Additionally, the pathomechanism of this disease is not sufficiently understood, and no treatment is currently available. Owing to the growing interest in the disease's progression, evaluating the quality of life (QoL) for patients with PSP has become crucial. This review emphasizes the significance of QoL evaluation and its feasibility for practical implications, serving as an initial foundation for future research focused on the well-being of individuals affected by PSP.

Comparison of MIBG uptake in the major salivary glands between Lewy body disease and progressive supranuclear palsy

Introduction

Cardiac sympathetic denervation is specific to Lewy body disease (LBD). In Parkinson's disease (PD), sympathetic denervation in the major salivary glands (parotid glands [PG] and submandibular glands [SMG]) has been demonstrated by 123I-metaiodobenzylguanidine (MIBG) scintigraphy. We compared sympathetic denervation in the MSG between PD, dementia with Lewy bodies (DLB), and progressive supranuclear palsy (PSP).

Methods

We recruited 81 patients with PD, 12 with DLB, 13 with PSP and 25 with control subjects. We evaluated MIBG uptake in the major salivary glands and heart using a quantitative semi-automatic method. We compared MIBG uptake between PD, DLB, and PSP patients and controls, and we evaluated disease sensitivity and specificity. We compared olfactory function with MIBG uptake between PD and PSP patients.

Results

MIBG uptake in the PG and SMG in the delayed phase was significantly lower in PD and DLB patients than in PSP patients and controls. Conversely, MIBG uptake in the major salivary glands and heart was comparable between PD and DLB. Between LBD and non-LBD, MIBG uptake showed 56-100 % specificity in the PG, while it had 55.6-87.5 % sensitivity in the SMG. Between PD and PSP, MIBG uptake in the PG and SMG had higher disease specificity than olfactory function, while the sensitivity of SMG MIBG uptake was comparable to olfactory function.

Conclusion

PD and DLB patients showed lower MIBG uptake in the major salivary glands than PSP patients, especially in the delayed phase. MIBG uptake in the major salivary glands may differentiate PD from hyposmic PSP.

Dorsal Column Spinal Cord Stimulation Attenuates Brain-Spine Connectivity through Locomotion- and Visuospatial-Specific Area Activation in Progressive Freezing of Gait

INTRODUCTION

Freezing of gait (FOG) is a clinical phenomenon with major life impairments and significant reduction in quality of life for affected patients. FOG is a feature of Parkinson's disease and a hallmark of primary progressive FOG, currently reclassified as Progressive Supranuclear Palsy-progressive gait freezing (PSP-PGF). The pathophysiology of FOG and particularly PGF, which is a rare degenerative disorder with a progressive natural history of gait decline, is poorly understood. Mechanistically, changes in oscillatory activity and synchronization in frontal cortical regions, the basal ganglia, and the midbrain locomotor region have been reported, indicating that dysrhythmic oscillations and coherence could play a causal role in the pathophysiology of FOG. Deep brain stimulation and spinal cord stimulation (SCS) have been tested as therapeutic neuromodulation avenues for FOG with mixed outcomes.

METHODS

We analyzed gait and balance in 3 patients with PSP-PGF who received percutaneous thoracic SCS and utilized magnetoencephalography (MEG), electroencephalography, and electromyography to evaluate functional connectivity between the brain and spine.

RESULTS

Gait and balance did not worsen over a 13-month period. This observation was accompanied by decreased beta-band spectral power in the whole brain and particularly in the basal ganglia. This was accompanied by increased functional connectivity in and between the sensorimotor cortices, basal ganglia, temporal cortex, and cerebellum, and a surge in corticomuscular coherence when SCS was paired with visual cues.

CONCLUSION

Our results suggest synergistic activity between brain and spinal circuits upon SCS for FOG in PGF, which may have implications for future brain-spine interfaces and closed-loop neuromodulation for patients with FOG.

Utilizing quantitative susceptibility mapping to differentiate primary lateral sclerosis from progressive supranuclear palsy: A case report

We report a patient who presented clinically with progressive supranuclear palsy (PSP) but was pathologically diagnosed as having primary lateral sclerosis (PLS) with magnetic resonance imaging (MRI) with a quantitative susceptibility mapping (QSM) protocol. A 70-year-old man was clinically diagnosed with PSP due to early falls and unresponsiveness to levodopa therapy. Postmortem pathological examination revealed mild loss of Betz cells, gliosis, and transactive response DNA binding protein of 43 kDa (TDP-43)-positive inclusions in the motor cortex, leading to the pathological diagnosis of PLS. To explore methods for differentiating PLS from PSP, ante-mortem QSM images were visually and quantitatively assessed for abnormal increases in magnetic susceptibility in the motor cortex. Prussian blue and Luxol fast blue combined with periodic acid-Schiff staining were also performed to understand the source of the susceptibility increases. QSM showed clear hyperintense signals in the motor cortex. Magnetic susceptibility in the motor cortex was higher in the PLS patient (Z = 4.7, p < 0.001) compared to normal controls and pathologically diagnosed PSP patients. Pathological examination of the region showed intracortical myelin loss, as well as iron deposition. Underlying pathological processes for the increased magnetic susceptibility include not only iron deposition but also intracortical myelin. Our case suggests that QSM is a potential tool to differentiate PLS from PSP, providing insights for accurate diagnosis and enhancing clinical decision-making.

Dysphagia in progressive supranuclear palsy: A scoping review

Introduction

One of the most prevalent types of atypical parkinsonian syndrome is progressive supranuclear palsy (PSP). PSP is associated with early onset of dysphagia which can result in malnutrition, dehydration, and aspiration pneumonia, affecting quality of life and increasing mortality rate. To date, research describing dysphagia in PSP and its impact is scant.

Methods

The objective of this scoping review is to determine the characteristics of dysphagia in PSP, differences in dysphagia presentation according to PSP subtype, principal methods used for identifying and diagnosing dysphagia and the impact dysphagia has on quality of life in individuals with PSP. This review was conducted in accordance with the JBI methodology. Six electronic databases were searched.

Results

Of the 20 studies included, the most frequently reported characteristics of dysphagia were oral preparatory and oral phase difficulties. A variety of methods were used to identify and diagnose dysphagia including instrumental assessment (65%), patient reported scales (45%) and clinical swallow evaluation (20%). The most used instrumental assessment was videofluoroscopy (46%). Limited data was available describing characteristics of dysphagia according to the subtype of PSP. The impact that dysphagia has on quality of life was assessed in only one study.

Conclusion

A range of assessment methods are used to identify and diagnose dysphagia in patients with PSP. Further research is needed to investigate if particular characteristics are associated with certain PSP subtypes. Future studies should also measure the impact that dysphagia has on quality of life in this population.

Genetic-based diagnostics of Parkinson's disease and other Parkinsonian syndromes

INTRODUCTION

Parkinson's disease (PD) is a complex disorder with vast clinical heterogeneity. Recent genetic, imaging and clinical evidence suggest that there are multiple subtypes of PD, and perhaps even distinct clinical entities, which are being diagnosed under the umbrella of PD. These might have similar clinical presentation, but potentially different underlying mechanisms, which, in future, will require different treatments. Despite extensive genetic research progress, genetic testing is still not a common practice in clinical patient care.

AREAS COVERED

This review examines the numerous genes that have been discovered to affect the risk of, or cause, PD. We also outline genetic variants that affect PD age at onset, its progression, and the presence or severity of motor and non-motor symptoms. We differentiate between PD, other synucleinopathies, and atypical parkinsonism syndromes, and describe genes responsible for familial forms of typical PD and atypical parkinsonism. Lastly, we present current clinical trails that are underway for targeted therapies, particularly for GBA1-PD and LRRK2-PD which are the most significant subtypes.

EXPERT OPINION

While genetic studies alone cannot be diagnostic for PD, proper utilization of genetic screening for PD could improve diagnostic accuracy and predictions for prognosis, guide treatment, and identify individuals that qualify for clinical trials.

Erythrocytic α-Synuclein in Parkinson's Disease and Progressive Supranuclear Palsy-A Pilot Study

Background/Objectives: The current research examines the accuracy of α-synuclein in RBCs as a diagnostic biomarker for PD and PSP, despite their distinct molecular etiologies. Methods: We used ELISA to measure total, oligomeric, and p129-α-synuclein levels in erythrocytes from 8 PSP patients, 19 PD patients, and 18 healthy controls (HCs). The classification performances of RBC α-synuclein levels were investigated by receiver operator characteristic (ROC) curve. We also evaluated a possible correlation between RBC α-synuclein level and the biological and clinical features of our cohorts. Results: RBC total α-synuclein was higher in PSP patients compared to both PD patients and HCs, achieving good classification performance (AUC: 0.853) in distinguishing PSP patients from PD patients, with a sensitivity of 100% and a specificity of 70.6%; moreover, the levels of this biomarker positively correlated with disease severity in PSP group. Regarding oligomeric α-synuclein and p129-α-synuclein, the latter was slightly increased in RBCs from PSP patients compared to HCs, but no correlations were detected. Conclusions: Although these findings need to be confirmed in larger studies, our pilot work suggests that RBC total α-synuclein may represent a potential molecular biomarker for the differential diagnosis and clinical staging of PSP.

Ethnic Differences in Atypical Parkinsonism-is South Asian PSP Different?

BACKGROUND

Progressive supranuclear palsy (PSP) is a progressive atypical parkinsonian condition that results in severe disability. There are few studies of PSP in patients of non-white European ancestry.

OBJECTIVES

We aim to perform deep phenotyping in a South Asian PSP cohort to uncover possible ethnic differences in disease characteristics.

METHODS

Consecutive PSP patients had their clinical records reviewed for clinical features operationalized in the Movement Disorder Society (MDS)-PSP diagnostic criteria and relevant investigations, including imaging and genetic tests. Clinical variables were summarized by descriptive statistics and Kaplan-Meier curves were generated for survival analysis.

RESULTS

Twenty-seven patients, comprising Indians (78%), Pakistanis (11%) and Sri Lankans (11%) were included. Mean age of symptom onset was 63.8 ± 7.0 years and 22% of patients had an early age of onset (<60 years). The most common presenting symptom was parkinsonism (56%), followed by cognitive dysfunction (37%), falls (33%) and dysarthria (26%). The predominance types at final review were distributed across PSP-RS (67%), PSP-PGF (15%), PSP-P (15%) and PSP-F (4%). Atypical clinical features like cerebellar signs (33%), REM-sleep behavior disorder (RBD) (55%), visual hallucinations (22%), and a family history of parkinsonism (20%) were evident in a proportion of patients.

CONCLUSIONS

We present a South Asian cohort of PSP patients with a higher than previously reported percentages of early-onset disease, family history and atypical clinical manifestations. These patients do not fit easily into the PSP phenotypes defined by the current MDS criteria. Dedicated clinicopathological and genetic tests are needed in this population to dissect the pathogenesis of clinically-defined PSP.

Neuropsychology and Movement Disorders

Neuropsychology is important in differential diagnosis, treatment planning, surgical work-up, and support of patients with movement disorders and their families. The cognitive profiles of several movement disorders are reviewed here. The authors also review relevant neuropsychologic literature related to neurosurgic intervention and cognitive-enhancing medication for patients with movement disorders.

Proximity Elongation Assay and ELISA for the Identification of Serum Diagnostic Biomarkers in Parkinson's Disease and Progressive Supranuclear Palsy

Clinical differentiation of progressive supranuclear palsy (PSP) from Parkinson's disease (PD) is challenging due to overlapping phenotypes and late onset of PSP specific symptoms, highlighting the need for easily assessable biomarkers. We used proximity elongation assay (PEA) to analyze 460 proteins in serum samples from 46 PD, 30 PSP patients, and 24 healthy controls. ANCOVA was used to identify the most promising proteins and machine learning (ML) XGBoost and random forest algorithms to assess their classification performance. Promising proteins were also quantified by ELISA. Moreover, correlations between serum biomarkers and biological and clinical features were investigated. We identified five proteins (TFF3, CPB1, OPG, CNTN1, TIMP4) showing different levels between PSP and PD, which achieved good performance (AUC: 0.892) when combined by ML. On the other hand, when the three most significant biomarkers (TFF3, CPB1 and OPG) were analyzed by ELISA, there was no difference between groups. Serum levels of TFF3 positively correlated with age in all subjects' groups, while for OPG and CPB1 such a correlation occurred in PSP patients only. Moreover, CPB1 positively correlated with disease severity in PD, while no correlations were observed in the PSP group. Overall, we identified CPB1 correlating with PD severity, which may support clinical staging of PD. In addition, our results showing discrepancy between PEA and ELISA technology suggest that caution should be used when translating proteomic findings into clinical practice.

Japanese longitudinal biomarker study in progressive supranuclear palsy and corticobasal degeneration: Clinical features of the first registered patients and short-term follow-up analysis

Introduction

Progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) manifest with variable clinical features. We initiated a multicenter prospective registry study-the Japanese Longitudinal Biomarker Study in PSP and CBD-in November 2014 at 45 Japanese institutions to collect clinical information and biological samples to elucidate the natural courses and diagnostic biomarkers of PSP/CBD.

Methods

Initial symptoms, clinical features, and scores (Progressive Supranuclear Palsy Rating Scale [PSPRS], Barthel Index, Mini-Mental State Examination, and Frontal Assessment Battery) of patients clinically diagnosed with PSP/corticobasal syndrome (CBS) at the first registration were analyzed. PSPRS score progression in the initial 8 years and predictive factors were examined.

Results

As of October 2022, first registration had been conducted for 349 patients-57 with probable/possible Richardson's syndrome (RS), 133 with possible CBS, 41 with overlapping CBS and PSP criteria (RS/CBS group), 20 with PSP subtypes other than RS, and 98 who did not fulfill the PSP or CBS criteria. Among the RS, CBS, and RS/CBS groups, the RS group exhibited the best scores. Initial symptoms of personality change and asymmetric onset were correlated with the total PSPRS score. The average PSPRS score increment by the second registration (n = 116 patients) was 11.8 in all three groups, and progression was correlated with cognitive dysfunction. Seventy patients died during the study period. The 5-year survival rate from onset was approximately 90 %.

Conclusion

There were fewer severe clinical features in the RS group than in the CBS group. Cognitive dysfunction may be important in predicting clinical severity and disease progression.

Relevance of 123I-FP-CIT SPECT prescriptions for the diagnosis of parkinsonian syndromes

123I-FP-CIT SPECT enables the detection of presynaptic dopaminergic denervation. It allows to differentiate degenerative parkinsonian syndromes from secondary parkinsonian syndromes or essential tremor, and patients with suspected dementia with Lewy bodies from those with other dementia subtypes. The aim of our study was to evaluate the appropriateness of 123I-FP-CIT SPECT prescriptions, identify prescriber profiles and analyze changes in prescriptions over a decade in the Neurology department of Avicenne University hospital. This retrospective study included all patients who underwent 123I-FP-CIT SPECT between February 2009 and May 2019 (n = 723). Clinical and paraclinical data were compared between three groups based on the relevance of 123I-FP-CIT SPECT prescription: "inappropriate", "uncertain" and "relevant". We showed that inappropriate indications accounted for 37.5% of 123I-FP-CIT SPECT requests. Hospital neurologists and neurologists with mixed practice accounted for 74.1% of 123I-FP-CIT SPECT requests, hospital movement disorders specialists being more likely to prescribe appropriately (67.1%) than hospital non-movement disorders specialists (33.3%). Following the replacement of the neuro-oncology team with a team including movement disorders specialists, the percentage of relevant SPECT 123I-FP-CIT prescriptions rose from 37.5% to 81.0%. These observations suggest that seeking the expertise of a movement disorders specialist would be more relevant than the systematic prescription of 123I-FP-CIT SPECT.

Multi-Class Detection of Neurodegenerative Diseases from EEG Signals Using Lightweight LSTM Neural Networks

Neurodegenerative diseases severely impact the life of millions of patients worldwide, and their occurrence is more and more increasing proportionally to longer life expectancy. Electroencephalography has become an important diagnostic tool for these diseases, due to its relatively simple procedure, but it requires analyzing a large number of data, often carrying a small fraction of informative content. For this reason, machine learning tools have gained a considerable relevance as an aid to classify potential signs of a specific disease, especially in its early stages, when treatments can be more effective. In this work, long short-term memory-based neural networks with different numbers of units were properly designed and trained after accurate data pre-processing, in order to perform a multi-class detection. To this end, a custom dataset of EEG recordings from subjects affected by five neurodegenerative diseases (Alzheimer's disease, frontotemporal dementia, dementia with Lewy bodies, progressive supranuclear palsy, and vascular dementia) was acquired. Experimental results show that an accuracy up to 98% was achieved with data belonging to different classes of disease, up to six including the control group, while not requiring particularly heavy computational resources.

Differentiating neurodegenerative diseases based on EEG complexity

Neurodegenerative diseases are common causes of impaired mobility and cognition in the elderly. Among them, tauopathies and α-synucleinopathies were considered. The neurodegenerative processes and relative differential diagnosis were addressed through a qEEG non-linear analytic method. Study aims were to test accuracy of the power law exponent β applied to EEG in differentiating neurodegenerative diseases and to explore differences in neuronal connectivity among different neurodegenerative processes based on β. N = 230 patients with a diagnosis of tauopathy or α-synucleinopathy and at least one artifact-free EEG recording were selected. Periodogram was applied to EEG signal epochs from continuous recordings. Power law exponent β was determined by the slope of the signal power spectrum versus frequency in logarithmic scale. A data-driven clustering based on β values was performed to identify independent subgroups. Data-driven clustering based on β differentiated tauopathies (overall lower β values) from α-synucleinopathies (higher β values) with high sensitivity and specificity. Tauopathies also presented lower values in the correlation coefficients matrix among frontal sites of recording. In conclusion, significant differences in β values were found between tauopathies and α-synucleinopathies. Hence, β is proposed as a possible biomarker of differential diagnosis and neuronal connectivity.

SNMMI Procedure Standard/EANM Practice Guideline for Brain [18F]FDG PET Imaging, Version 2.0

PREAMBLEThe Society of Nuclear Medicine and Molecular Imaging (SNMMI) is an international scientific and professional organization founded in 1954 to promote the science, technology, and practical application of nuclear medicine. The European Association of Nuclear Medicine (EANM) is a professional nonprofit medical association that facilitates communication worldwide between individuals pursuing clinical and research excellence in nuclear medicine. The EANM was founded in 1985. The EANM was founded in 1985. SNMMI and EANM members are physicians, technologists, and scientists specializing in the research and practice of nuclear medicine.The SNMMI and EANM will periodically define new guidelines for nuclear medicine practice to help advance the science of nuclear medicine and to improve the quality of service to patients throughout the world. Existing practice guidelines will be reviewed for revision or renewal, as appropriate, on their fifth anniversary or sooner, if indicated.Each practice guideline, representing a policy statement by the SNMMI/EANM, has undergone a thorough consensus process in which it has been subjected to extensive review. The SNMMI and EANM recognize that the safe and effective use of diagnostic nuclear medicine imaging requires specific training, skills, and techniques, as described in each document. Reproduction or modification of the published practice guideline by those entities not providing these services is not authorized.These guidelines are an educational tool designed to assist practitioners in providing appropriate care for patients. They are not inflexible rules or requirements of practice and are not intended, nor should they be used, to establish a legal standard of care. For these reasons and those set forth below, both the SNMMI and the EANM caution against the use of these guidelines in litigation in which the clinical decisions of a practitioner are called into question.The ultimate judgment regarding the propriety of any specific procedure or course of action must be made by the physician or medical physicist in light of all the circumstances presented. Thus, there is no implication that an approach differing from the guidelines, standing alone, is below the standard of care. To the contrary, a conscientious practitioner may responsibly adopt a course of action different from that set forth in the guidelines when, in the reasonable judgment of the practitioner, such course of action is indicated by the condition of the patient, limitations of available resources, or advances in knowledge or technology subsequent to publication of the guidelines.The practice of medicine includes both the art and the science of the prevention, diagnosis, alleviation, and treatment of disease. The variety and complexity of human conditions make it impossible to always reach the most appropriate diagnosis or to predict with certainty a particular response to treatment.Therefore, it should be recognized that adherence to these guidelines will not ensure an accurate diagnosis or a successful outcome. All that should be expected is that the practitioner will follow a reasonable course of action based on current knowledge, available resources, and the needs of the patient to deliver effective and safe medical care. The sole purpose of these guidelines is to assist practitioners in achieving this objective.

Legumain/asparaginyl endopeptidase-resistant tau fibril fold produces corticobasal degeneration-specific C-terminal tau fragment

Corticobasal degeneration (CBD) is a major four-repeat tauopathy along with progressive supranuclear palsy (PSP). Although detergent-insoluble 37-40-kDa carboxyl-terminal tau fragments (CTFs) are hallmarks of CBD pathology, the process of their formation is unknown. This study monitored the formation of CBD-type fibrils that exhibit astrocytic plaques, a characteristic CBD pathology, using its biochemical properties different from those of Alzheimer's disease/PSP-type fibrils. Tau fibrils from patients with CBD were amplified in non-astrocytic cultured cells, which maintained CBD-specific biochemical properties. We found that the lysosomal protease Legumain (LGMN) was involved in the generation of CBD-specific 37-40-kDa CTFs. While LGMN cleaved tau fibrils at Asn167 and Asn368 in the brain tissues of patients with Alzheimer's disease and PSP, tau fibrils from patients with CBD were predominantly resistant to cleavage at Asn368 by LGMN, resulting in the generation of CBD-specific CTFs. LGMN preference in tau fibrils was lost upon unraveling the tau fibril fold, suggesting that the CBD-specific tau fibril fold contributes to CBD-specific CTF production. From these findings, we found a way to differentiate astrocytic plaque from tufted astrocyte using the anti-Asn368 LGMN cleavage site-specific antibody. Inoculation of tau fibrils amplified in non-astrocytic cells into the mouse brain reproduced LGMN-resistant tau fibrils and recapitulated anti-Asn368-negative astrocytic plaques, which are characteristic of CBD pathology. This study supports the existence of disease-specific tau fibrils and contribute to further understanding of the tauopathy diagnosis. Our tau propagation mouse model using cellular tau seeds may contribute to uncovering disease mechanisms and screening for potential therapeutic compounds.

Tau load in select brainstem neurons predicts the severity and nature of balance deficits in the absence of cell death

Patients with tauopathies present with profoundly different clinical symptoms 1 , even within the same disorder 2 . A central hypothesis in the field, well-supported by biomarker studies 3,4 and post-mortem pathology 5-7 , is that clinical heterogeneity reflects differential degeneration of vulnerable neuronal populations responsible for specific neurological functions. Recent work has revealed mechanisms underlying susceptibility of particular cell types 8-10 , but relating tau load to disrupted behavior - es- pecially before cell death - requires a targeted circuit-level approach. Here we studied two distinct balance behaviors in larval zebrafish 11 expressing a human 0N/4R-tau allele 12 in select populations of evolutionarily-conserved and well-characterized brainstem vestibular circuits 13,14 . We observed that human tau load predicted the severity of circuit-specific deficits in posture and navigation in the ab- sence of cell death. Targeting expression to either mid- or hindbrain balance neurons recapitulated these particular deficits in posture and navigation. By parametrically linking tau load in specific neu- rons to early behavioral deficits, our work moves beyond cell type to close the gap between pathological and neurological conceptions of tauopathy.

Autoimmune Encephalitis and Paraneoplastic Neurological Syndromes with Progressive Supranuclear Palsy-like Manifestations

BACKGROUND

Advances in diagnostic procedures have led to an increasing rate of diagnosis of autoimmune encephalitis or paraneoplastic neurological syndrome (AE/PNS) among patients with progressive supranuclear palsy (PSP)-like manifestations.

METHODS

In this narrative review, we first discuss the clinical characteristics of AE/PNS in comparison to those of PSP, followed by a discussion of diagnosis and treatment.

RESULTS

The antibodies involved in these conditions include anti-IgLON5, -Ma2, and -Ri antibodies, each of which has a characteristic clinical presentation. The steps in the diagnosis of AE/PNS in patients with PSP-like manifestations include (i) suspicion of AE/PNS based on clinical presentations atypical of PSP and (ii) antibody detection measures. Methods used to identify antibodies include a combination of tissue-based assays and confirmatory tests. The primary confirmatory tests include cell-based assays and immunoblotting. Treatments can be divided into immunotherapy and tumor therapies, the former of which includes acute and maintenance therapies.

CONCLUSIONS

One of the major challenges of diagnosis is that existing reports on PSP-like patients with AE/PNS include only case reports, with the majority discussing antibodies other than anti-IgLON5 antibody. As such, more patients need to be evaluated to establish the relationship between antibodies and PSP-like manifestations.

MRI-Based Multi-Class Relevance Vector Machine Classification of Neurodegenerative Diseases

Machine learning algorithms are a promising automated candidate that can help mitigate the growing need for dementia experts. Despite the substantial development in MRI-based machine learning analyses, case misclassification is a universal finding, yet the reasons behind misclassification are poorly understood. We implemented a multi-class classification approach that uses relevance vector machine and logistic classification to classify research participants based on their whole-brain T1-weighted MRI scans. A total of 468 participants from seven diagnostic classes were included: 144 healthy controls, 84 Alzheimer's disease, 108 behavioral variant frontotemporal dementia (bvFTD), 30 semantic variant primary progressive aphasia (svPPA), 30 non-fluent variant primary progressive aphasia (nfvPPA), 30 corticobasal syndrome (CBS), and 42 progressive supranuclear palsy syndrome (PSPS). We compared the algorithm's diagnostic accuracy against the clinical, pathological, genetic, and quantitative imaging data. The exact neurodegenerative syndrome was predicted in 71% of the cases, the neurodegenerative disease spectrum was predicted in 80% of the cases, and the algorithm distinguished controls from any dementia in 85% of the cases. The algorithm showed high performance in diagnosing healthy controls, moderate performance in diagnosing AD, bvFTD, and svPPA, and low performance in diagnosing CBS, nfvPPA, and PSPS. Based on the quantitative imaging data, most of the misclassified neurodegenerative cases had minimal atrophy and brain volumes comparable to healthy controls. In AD, early-onset AD cases with minimal brain atrophy represented most of the misclassified cases. In bvFTD, FTD genetic mutation carriers (predominantly C9orf72 repeat expansion), FTD phenocopy, patients meeting only possible bvFTD criteria represented most misclassified cases. Case misclassification in machine learning studies in neurodegenerative diseases results from neurodegenerative disease heterogeneity and the limitations of structural MRI's ability to capture the whole gamut of biological changes. Larger and more inclusive datasets that are representative of population biologic heterogeneity are needed to train better machine learning techniques, and a margin of error is expected and should be acceptable, like the uncertainty of a clinical diagnosis by a dementia expert.

Predictors of Care Home Admission and Survival Rate in Patients With Syndromes Associated With Frontotemporal Lobar Degeneration in Europe

BACKGROUND AND OBJECTIVES

Data on care home admission and survival rates of patients with syndromes associated with frontotemporal lobar degeneration (FTLD) are limited. However, their estimation is essential to plan trials and assess the efficacy of intervention. Population-based registers provide unique samples for this estimate. The aim of this study was to assess care home admission rate, survival rate, and their predictors in incident patients with FTLD-associated syndromes from the European FRONTIERS register-based study.

METHODS

We conducted a prospective longitudinal multinational observational registry study, considering incident patients with FTLD-associated syndromes diagnosed between June 1, 2018, and May 31, 2019, and followed for up to 5 years till May 31, 2023. We enrolled patients fulfilling diagnosis of the behavioral variant frontotemporal dementia (bvFTD), primary progressive aphasia (PPA), progressive supranuclear palsy (PSP) or corticobasal syndrome (CBS), and FTD with motor neuron disease (FTD-MND). Kaplan-Meier analysis and Cox multivariable regression models were used to assess care home admission and survival rates. The survival probability score (SPS) was computed based on independent predictors of survivorship.

RESULTS

A total of 266 incident patients with FTLD were included (mean age ± SD = 66.7 ± 9.0; female = 41.4%). The median care home admission rate was 97 months (95% CIs 86-98) from disease onset and 57 months (95% CIs 56-58) from diagnosis. The median survival was 90 months (95% CIs 77-97) from disease onset and 49 months (95% CIs 44-58) from diagnosis. Survival from diagnosis was shorter in FTD-MND (hazard ratio [HR] 4.59, 95% CIs 2.49-8.76, p < 0.001) and PSP/CBS (HR 1.56, 95% CIs 1.01-2.42, p = 0.044) compared with bvFTD; no differences between PPA and bvFTD were found. The SPS proved high accuracy in predicting 1-year survival probability (area under the receiver operating characteristic curve = 0.789, 95% CIs 0.69-0.87), when defined by age, European area of residency, extrapyramidal symptoms, and MND at diagnosis.

DISCUSSION

In FTLD-associated syndromes, survival rates differ according to clinical features and geography. The SPS was able to predict prognosis at individual patient level with an accuracy of ∼80% and may help to improve patient stratification in clinical trials. Future confirmatory studies considering different populations are needed.

Cerebrospinal Fluid Total, Phosphorylated and Oligomeric A-Synuclein in Parkinson's Disease: A Systematic Review, Meta-Analysis and Meta-Regression Study

Background: The diagnostic accuracy for Parkinson's disease (PD), a synucleinopathy, based on diagnostic criteria is suboptimal. A biomarker for synucleinopathies is pivotal both from a clinical and from a research point of view. CSF a-synuclein has been extensively studied over the past two decades as a candidate biomarker of synucleinopathies. Herein, we present data on studies focusing on total, phosphorylated and oligomeric CSF a-synuclein in PD. Methods: Pubmed, Scopus and Web of Science were searched for studies with >10 PD patients and control subjects, with data (mean, SD) on total, phosphorylated or oligomeric a-synuclein. Cohen's d, as a measure of effect size, was calculated for all a-synuclein forms. Subgroup analysis and meta-regression were performed in an effort to explain between-study heterogeneity. Results: Thirty studies on total, six studies on oligomeric and one study on phosphorylated a-synuclein were included. Total a-synuclein was decreased and oligomeric a-synuclein increased in PD patients vs. controls. The effect size was medium for total and high for oligomeric a-synuclein. A-syn forms provided suboptimal combined sensitivity/specificity for the differentiation of PD from controls. There was significant between-study heterogeneity. The PD cohort characteristics (sex, age, disease duration, UPDRS, H & Y) and study characteristics (study design, healthy vs. neurological controls, control for CSF blood contamination, method of a-syn measurement) could not account for between-study heterogeneity. Publication bias was limited. Conclusions: CSF a-synuclein levels lack sufficient accuracy to be used as biomarkers for PD. The standardization of (pre)analytical variables may improve the discriminatory power of a-synuclein forms in the future.

Current Perspectives on Olfactory Loss in Atypical Parkinsonisms-A Review Article

INTRODUCTION

Atypical parkinsonisms (APs) present various symptoms including motor impairment, cognitive decline, and autonomic dysfunction. Olfactory loss (OL), being a significant non-motor symptom, has emerged as an under-evaluated, yet potentially valuable, feature that might aid in the differential diagnosis of APs.

STATE OF THE ART

The most pronounced OL is usually associated with Dementia with Lewy Bodies (DLB). While the view about the normosmic course of Multiple System Atrophy (MSA) remains unchanged, research indicates that mild OL may occur in a subset of patients with Progressive Supranuclear Palsy (PSP) and Corticobasal Degeneration (CBD). This might be linked to the deposition of abnormal protein aggregates in the central nervous system.

CLINICAL SIGNIFICANCE

The aim of this review is to discuss the role of OL and its degree and pattern in the pathogenesis and course of APs. Olfactory testing could serve as a non-invasive, quick screening tool to differentiate between APs and project disease progression.

FUTURE DIRECTIONS

There is a need for further evaluation of this topic. This may lead to the development of standardized olfactory testing protocols that could be implemented in clinical practice, making differential diagnosis of APs more convenient. Understanding differences in the sense of smell could create an avenue for more targeted therapeutic strategies.

Monocyte to high-density lipoprotein cholesterol ratio reflects the peripheral inflammatory state in parkinsonian disorders

BACKGROUND

In Parkinson's disease (PD) and Parkinson plus syndrome (PPS), inflammation is recognized as a relevant or contributing factor in the advancement of the diseases. For this reason, numerous biomarkers signaling immune alteration in both the central and peripheral nervous systems have been evaluated in PD and PPS. Nonetheless, the comprehensive inflammatory indices derived from readily available standard blood tests in PD, PPS, and healthy controls (HC) were rarely evaluated especially in the early stage of the diseases.

OBJECTIVE

The aim of this study is to explore the serum level of peripheral inflammatory markers among the patients and investigate whether these markers contribute to symptoms.

METHOD

Clinical data and blood test results from drug naïve, early-stage 139 PD and 87 PPS patients, along with 139 age- and sex-matched healthy controls (HC) to PD were enrolled, with exclusion criteria applied to conditions potentially affecting inflammation. The study examined the disparities in peripheral inflammation among the groups, using total and subpopulation of white blood cells (WBCs), platelet count, red cell distribution width (RDW), high-density lipoprotein cholesterol (HDL-C), and other composite values reflecting inflammation including RDW to platelet ratio (RPR), neutrophil to lymphocyte ratio (NLR), monocyte to lymphocyte ratio (MLR), platelet to lymphocyte ratio (PLR), neutrophil to HDL-C ratio (NHR), monocyte to HDL-C ratio (MHR), lymphocyte to HDL-C ratio (LHR), platelet to HDL-C ratio (PHR), systemic inflammation index (SII), systemic inflammation response index (SIRI), and aggregate index of systemic inflammation (AISI).

RESULT

The MHR values were significantly higher in both PD and PPS groups compared to HC (p < 0.001), and NHR was significantly higher in the PPS group only compared to the HC group (p < 0.001). However, no significant differences in all the inflammatory markers were observed between PPS and PD (p > 0.05). Subgroup analysis of progressive supranuclear palsy (PSP) and multiple system atrophy (MSA) patients revealed significantly higher NHR and MHR levels compared to the HC group (p = 0.025, p = 0.050, respectively), with no significant difference among PSP, MSA, and PD groups. After adjustment for age, sex, and disease duration, MHR was positively associated with H&Y in the total population (β = 0.288, p < 0.001), negatively associated with MMSE in the PD group (β = -0.245, p = 0.017), and positively associated with both H&Y (β = 0.432, p < 0.001) and UPDRS part II (β = 0.295, p = 0.018) in PPS group.

CONCLUSION

NHR and MHR values are not effective as reliable diagnostic markers due to overlap among groups and their limited discriminative capacity in ROC analyses. However, MHR may potentially serve as an indicator reflecting peripheral inflammation in the early stage of PD and PPS compared to HC.

The possible connection between neutrophil-to-high-density lipoprotein ratio and cerebral perfusion in clinically established corticobasal syndrome: a pilot study

Introduction

Progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS) are tauopathic atypical parkinsonisms. Given their overlap in terms of clinical manifestation, there is growing interest in the mechanisms leading to these entities.

Materials and methods

In total, 71 patients were included in the study, 19 of whom were clinically diagnosed with CBS, 37 with PSP, and 15 with Parkinson's disease (PD). The mean ages of the participants were 72.8, 72.9, and 64.0 years, respectively, and the disease duration varied from 3 to 6 years. Each individual underwent blood collection. Morphological and biochemical evaluation of blood samples was performed to analyze the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and neutrophil-to-high-density lipoprotein ratio (NHR). A single-photon emission computed tomography (SPECT) with technetium-99m hexamethylpropyleneamine oxime (99Tc-HMPAO) tracer was used to assess perfusion in two regions of interest (ROI): the thalamus and insula. Using Pearson correlation to assess the linear relationship between NHR and perfusion in the insula and thalamus for CBS, PSP, and PD patients, the authors intended to verify possible correlations between NLR, PLR, and NHR and perfusion in the indicated ROIs.

Results

The study revealed a negative linear correlation between NHR and perfusion of both the left (Insula L; R = -0.59) and right (Insula R; R = -0.58) insula regions. Similar to the insula, a linear correlation between NHR and activity in both the left (Thalamus L) and right (Thalamus R) thalamus regions in CBS subjects with a relatively stronger correlation in the right thalamus (R = -0.64 vs. R = -0.58) was found. These observations were not confirmed in PSP and PD patients.

Conclusion

Simultaneously using non-specific parameters for peripheral inflammation (NLR, PLR, and NHR) and perfusion, SPECT may be an interesting beginning point for further analysis of inflammatory disease mechanisms. To the best of our knowledge, this is the first study to address the potential correlation between the peripheral neuroinflammatory markers NLR, PLR, and NHR and perfusion disturbances in particular ROIs.

Toward an animal model of Progressive Supranuclear Palsy

Progressive Supranuclear Palsy (PSP) is a rare and fatal neurodegenerative tauopathy which, with a rapid clinical progression coupled to a strong degree of clinico-pathologic correlation, has been suggested to be a "frontrunner" in translational development for neurodegenerative proteinopathies. Elegant studies in animals have contributed greatly to our understanding of disease pathogenesis in PSP. However, presently no animal model replicates the key anatomical and cytopathologic hallmarks, the spatiotemporal spread of pathology, progressive neurodegeneration, or locomotor and cognitive symptoms that characterize PSP. Current models therefore likely fail to recapitulate the key mechanisms that underly the pathological progression of PSP, impeding their translational value. Here we review what we have learned about PSP from work in animals to date, examine the gaps in modeling the disease and discuss strategies for the development of refined animal models that will improve our understanding of disease pathogenesis and provide a critical platform for the testing of novel therapeutics for this devastating disease.

Rapid Eye Movements during REM Sleep Differentiate PSP from Parkinson's Disease

BACKGROUND

Little is known about the characteristics and occurrence frequencies of rapid eye movements (REMs) during REM sleep in movement disorders.

OBJECTIVES

The aim of this study was to detect and characterize REMs during polysomnographically defined REM sleep as recorded by electro-oculography (EOG) in 12 patients with progressive supranuclear palsy (PSP), 13 patients with Parkinson's disease (PD) and 12 healthy controls.

METHODS

Using a modified EOG montage, we developed an algorithm that automatically detects and characterizes REMs during REM sleep based on their presumptive saccadic kinematics.

RESULTS

Compared to PD and healthy controls, REM densities and REM peak velocities were significantly reduced in PSP. These effects were most pronounced in vertical REMs.

CONCLUSION

Ocular motor dysfunction, one of the cardinal features of PSP, seems to be equally at play during REM sleep and wakefulness. For future studies, we provide a novel tool for the unbiased analysis of REMs during REM sleep in movement disorders.

The contribution of white matter changes to clinical phenotype in progressive supranuclear palsy

White matter hyperintensities (WMH) are considered magnetic brain imaging (MRI) biomarkers of cerebral small vessel disease but their clinical role in neurodegenerative-related disorders is poorly understood. This study describes the distribution of WMH on brain MRI in Progressive Supranuclear Palsy (PSP) in comparison with Parkinson's disease (PD) and explores their possible impact on disease's features. Sixty PSP and 33 PD patients were included. Motor symptoms, cardiovascular risk factors and the age-related white matter changes (ARWMC) score was computed to rate WMH for both groups. Pearson's correlation and linear or logistic regression analysis were used to check for relationships between ARWMC and PSP clinical scores. The mean (standard deviation) ARWMC total score in the PSP cohort was 4.66 (3.25). Any degree of WMH was present in 68% of PSP (ARWMC +). Compared to ARWMC-, ARWMC + did not have greater disease severity or more cardiovascular risk factors. WMH were frequently localized in fronto-parietal lobes and were mild in severity. Linear regression analysis showed that ARWMC total score was related to the PSP-rating scale, irrespective of age, disease duration and the Charlson modified comorbidity index. Logistic regression analysis confirmed that ARWMC total score was related to the use of wheelchair, irrespective of above-mentioned covariates. Vascular risk factors as well as severity and distribution of WMH did not have an impact on the PSP phenotype. No differences were found with PD patients. Our results suggest that WMH in PSP might be markers of neurodegenerative-related pathology rather than being simple expression of atherosclerotic cerebrovascular changes.

SEND-PD in Parkinsonian Syndromes: Results of a Monocentric Cross-Sectional Study

Introduction

Neuropsychiatric symptoms in particular impair health-related quality of life (QoL) of patients with Parkinson's disease and atypical Parkinsonian syndromes. For this reason, various scales have been developed for detection of neuropsychiatric symptoms, such as the Scale for evaluation of neuropsychiatric disorders in Parkinson's disease (SEND-PD).

Objective

First, the objective of this study was to explore the interrelation between the SEND-PD and clinical parameters in patients with Parkinson's disease and thus confirm its validity. In addition, the applicability in a well-defined cohort of patients with atypical Parkinsonian syndromes was investigated for the very first time.

Methods

A clinically well-defined cohort of 122 patients with Parkinson's disease (PD), 55 patients with Progressive Supranuclear Palsy (PSP) and 33 patients with Multiple System Atrophy (MSA) were analyzed. First, the SEND-PD was correlated with established disease-specific scores in patients with PD. Next, the results of the SEND-PD were compared between the different Parkinsonian syndromes.

Results

The SEND-PD showed a strong significant correlation with several scores, especially the UPDRS I (Rho = 0.655) and GDS-15 (Rho = 0.645). Depressive burden was significantly higher in MSA patients in comparison to the PD patient cohort (PD, 3.8 ± 3.3; MSA, 5.45 ± 3.87), while PSP patients showed significantly less psychotic (PD 1.6 ± 2.1; PSP 0.6 ± 0.9) and impulse control disorders (PD 0.3 ± 1.0; PSP 0.02 ± 0.1).

Conclusion

The SEND-PD is a useful, brief and highly applicable screening tool for neuropsychiatric symptoms in PD, but not in atypical Parkinsonism, as their unique neuropsychiatric symptom composition is not fully captured.

Systematic assessment of square-wave jerks in progressive supranuclear palsy: a video-oculographic study

BACKGROUND

The presence of frequent macro-square-wave jerks (SWJs) has been recently included in the diagnostic criteria for progressive supranuclear palsy (PSP). The aim of the current video-oculographic study was to systematically assess the presence and features of SWJs during a brief fixation task in PSP, in comparison with Parkinson's disease (PD) patients and healthy controls (HC).

METHODS

Thirty-eight PSP patients, 55 PD patients and 40 HC were enrolled in the study. All patients underwent a video-oculographic (VOG) examination including a 5-s fixation task, and the number, duration and amplitude of SWJs were recorded. The diagnostic performance of several SWJs parameters were then compared in distinguishing PSP from PD patients and controls.

RESULTS

PSP patients showed a higher number and amplitude of SWJs compared to PD patients and controls. At least two SWJs within the 5-s fixation task were observed in 81.6% of PSP patients, 52.7% of PD patients and 25% of HC. The SWJs amplitude was the parameter showing the highest performances in distinguishing PSP from PD (AUC: 0.78) and HC (AUC: 0.88), outperforming the SWJ number and duration. The SWJ amplitude was larger in PSP-Richardson's syndrome than in PSP-Parkinsonism patients, while no difference was found between PSP patients with different degrees of vertical ocular motor dysfunction.

CONCLUSIONS

This video-oculographic study provides robust evidence of larger SWJs number and amplitude in PSP than in PD patients, with some potential for differential diagnosis, supporting the inclusion of this ocular sign in PSP criteria.

Induction of tau pathology and motor dysfunction in mice by urinary exosomes from progressive supranuclear palsy patients

BACKGROUND

Progressive supranuclear palsy (PSP) is characterized by the presence of hyperphosphorylated and misfolded tau aggregates in neurons and glia. Recent studies have illuminated the prion-like cell-to-cell propagation of tau via exosomes. Recognizing the potential significance of excretion through urine as a crucial pathway for eliminating pathological tau from the central nervous system, this study aimed to investigate whether exosomes derived from the urine of PSP-Richardson's syndrome (PSP-RS) patients can elicit tau pathology and PSP-like symptoms in mice.

METHODS

Urinary exosomes obtained from PSP-RS patients and normal controls (NCs) were stereotactically injected into the bilateral globus pallidus of mouse brains. Behavioral analyses were conducted every 3 months post-injection. After 6 months, mice were sacrificed for pathological evaluation.

RESULTS

Elevated levels of phosphorylated tau and neural cell markers were observed in urinary exosomes from PSP-RS patients compared to NCs. At the 6-month mark post-injection, tau inclusions were evident in the brains of mice receiving urinary exosomes from PSP-RS patients, with widespread distribution in both injection sites and distant brain regions (cortex, hippocampus, and substantia nigra). Tau pathology manifested in neurons and astrocytes. Moreover, mice injected with urinary exosomes from PSP-RS patients exhibited impaired motor coordination and balance, mirroring PSP motor symptoms.

CONCLUSION

Our findings indicate that urinary exosomes from PSP-RS patients can induce tau pathology and trigger PSP-like motor symptoms in mice. This leads to the hypothesis that exosomes may play a role in the pathogenesis of PSP.