Background: Various MRI markers—including midbrain and pons areas (M_area, P_area) and volumes (M_vol, P_vol), ratios (M/P_area, M/P_vol), and composite markers (magnetic resonance imaging Parkinsonism Indices 1,2; MRPI 1,2)—have been proposed as imaging markers of Richardson’s syndrome (RS) and multiple system atrophy–Parkinsonism (MSA-P). A systematic review/meta-analysis of relevant studies aiming to compare the diagnostic accuracy of these imaging markers is lacking. Methods: Pubmed and Scopus were searched for studies with >10 patients (RS, MSA-P or CBS) and >10 controls with data on M_area, P_area, M_vol, P_vol, M/P_area, M/P_vol, MRPI 1, and MRPI 2. Cohen’s d, as a measure of effect size, was calculated for all markers in RS, MSA-P, and CBS. Results: Twenty-five studies on RS, five studies on MSA-P, and four studies on CBS were included. Midbrain area provided the greatest effect size for differentiating RS from controls (Cohen’s d = −3.10; p < 0.001), followed by M/P_area and MRPI 1. MSA-P had decreased midbrain and pontine areas. Included studies exhibited high heterogeneity, whereas publication bias was low. Conclusions: Midbrain area is the optimal MRI marker for RS, and pons area is optimal for MSA-P. M/P_area and MRPIs produce smaller effect sizes for differentiating RS from controls.

(1) Background: Frontotemporal lobar degeneration (FTLD) is a generic term which refers to multiple pathologies, including FTLD-tau. The most common FTLD-tau diseases are Pick’s disease (PiD), progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). These diseases share four major syndromes: behavioral variant frontotemporal dementia (bvFD), Richardson syndrome (RS), corticobasal syndrome (CBS) and non-fluent agrammatic primary progressive aphasia (nfa-PPA). The primary aim of this meta-analysis was to examine the diagnostic performance of CSF total (t-tau) and phosphorylated (p-tau) protein in bvFTD, RS, CBS, nfa-PPA and pathologically or genetically defined tauopathy. (2) Methods: A systematic review and meta-analysis was performed on all studies with >10 subjects in a bvFTD/RS/CBS/nfa-PPA group and control group and available data on CSF t-tau or p-tau (mean, SD). Cohen’s d was used to quantify the effect size of each study (3) Results: The PSP/tauopathy patients exhibited decreased levels of CSF p-tau compared to the control subjects. The CBS/bvFTD/nfa-PPA cohorts exhibited an increase in t-tau compared to the control groups. (4) Conclusions: Tauopathies may exhibit an inherent decrease in CSF p-tau. The admixture of AD patients in FTD cohorts and high heterogeneity among studies on rare diseases are significant confounding factors in FTLD studies.

Introduction: Multiple MRI markers have been introduced as surrogate markers of progressive supranuclear palsy (PSP). Midbrain surface, midbrain/pons surface ratio (M/P) and the Magnetic Resonance Parkinsonism Index (MRPI) have produced high diagnostic accuracy in differentiating PSP from other parkinsonian disorders. A systematic comparison of the diagnostic accuracy of available MRI markers, and the effect of disease duration, clinical presentation, level of clinical certainty on the performance of these markers is lacking. Materials and methods: In this single-center, retrospective study, 244 subjects were included (80 PSP, 38 corticobasal degeneration, 45 multiple system atrophy, 36 Parkinson’s disease patients, 45 control subjects). All patients underwent a standardized MRI acquisition protocol and automated MRI data preprocessing through Freesurfer for volumetric data. Midbrain distance, surface and volume, superior cerebellar peduncle (SCP) width and volume, and composite markers including the M/P and M/P 2.0 ratios and the MRPI and MRPI 2.0 were measured. The diagnostic accuracy of these markers was calculated, and the effect of clinical phenotype, level of disease certainty and disease duration were investigated. Results: Surface-based MRI markers were superior to distance- and volume-based markers. Midbrain surface was the optimal MRI marker for PSP (AUC = 0.937; sensitivity 88.8%; specificity 84.2%). MRI markers were more accurate in diagnosing probable PSP vs. possible/suggestive PSP and PSP-Richardson syndrome vs. PSP variants. MRI markers exhibited comparable diagnostic accuracy in early (≤ 24 months) vs. late (≤ 48 months) disease stages. Midbrain atrophy correlated with PSP disease severity as well as ocular motor, gait and bulbar deficit severity. Discussion: Planimetric MRI markers are optimal for PSP diagnosis. Level of disease certainty (i.e. probable vs. possible/suggestive) and clinical presentation (PSP-RS vs. PSP variants) affect the diagnostic accuracy of MRI markers. MRI markers are useful even in early (≤ 24 months) stages of PSP.

Introduction: The prevalence of essential tremor (ET) demonstrates substantial differences across study populations and has been assessed in more than 40 population-based studies, but never in Greece. We directly estimated the prevalence of ET in community-dwelling adults aged 65 years and older, which was the age group expected to have the highest prevalence. Methods: Participants in a population-representative cohort aged ≥65 years underwent a neurological evaluation. ET was operationally defined as a Bain and Findley scale score ≥4 on the Archimedes’ spirals drawn with the more affected arm, excluding alternative causes of tremor. In a subset of participants, we validated this against diagnoses of ET assigned based on videotaped neurological examination. Logistic regression models were performed to assess independent effects of age and sex on prevalence. Results: A total of 172 of 1,926 participants were classified as having ET, corresponding to a crude prevalence of 8.9% (95% confidence interval [CI] = 7.7%, 10.2%). The prevalence of ET increased with increasing age (65–69: 6.4%; 70–74: 6.6%; 75–79: 12.1%; ≥80: 14.1%, X2 test, p < 0.001) and was higher in male than female participants (11.7% vs. 7.0%, X2 test, p < 0.001). Both age and sex were significant predictors of ET, when assessed simultaneously using logistic regression – odds ratio (95% CIs) = 1.07 (1.04, 1.10) and 1.54 (1.11, 2.12), respectively. Discussion: Our study provides the first estimate of ET prevalence in Greece and shows that ET is highly prevalent as it affects 8.9% of Greeks aged ≥65.