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Objective: We aimed to identify the brain structures associated with postural instability (PI) in Progressive Supranuclear Palsy (PSP)., Methods: Forty-seven PSP patients and 45 control subjects were enrolled in this study. PI was assessed using the items 27 and 28 of the PSP rating scale (postural instability score, PIS). PSP patients were compared with controls using voxel-based morphometry (VBM). In PSP patients, LASSO regression model was used to investigate associations between VBM-based Region-Of-Interest grey matter (GM) volumes and different categories of the PSP rating scale. A whole-brain multi-regression analysis was also used to identify brain areas where GM volumes correlated with the PIS in PSP patients., Results: VBM analysis showed widespread GM atrophy (fronto-temporal-parietal-occipital regions, limbic lobes, insula, cerebellum, and basal ganglia) in PSP patients compared with control subjects. In PSP patients, LASSO regression analysis showed associations of the right cerebellar lobules IV-V with ocular motor category score, and the left Rolandic area with bulbar category score, while the right inferior frontal gyrus (IFG) was negatively correlated with the PIS. The whole-brain multi-regression analysis identified the right IFG as the only area significantly associated with the PIS., Conclusions: In our study, two different approaches demonstrated that the IFG volume was associated with PIS in PSP patients, suggesting that this area may play a role in the pathophysiological mechanisms underlying PI. Our findings may have important implications for developing optimal Transcranial Magnetic Stimulation protocols targeting IFG in parkinsonism with postural disorders., Competing Interests: Declaration of competing interest None., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Introduction: Progressive supranuclear palsy (PSP) and idiopathic normal pressure hydrocephalus (iNPH) share several clinical and radiological features, making the differential diagnosis challenging. In this study, we aimed to differentiate between these two diseases using a machine learning approach based on cortical thickness and volumetric data., Methods: Twenty-three iNPH patients, 50 PSP patients and 55 control subjects were enrolled. All participants underwent a brain 3T-MRI, and cortical thickness and volumes were extracted using Freesurfer 6 on T1-weighted images and compared among groups. Finally, the performance of a machine learning approach with random forest using the extracted cortical features was investigated to differentiate between iNPH and PSP patients., Results: iNPH patients showed cortical thinning and volume loss in the frontal lobe, temporal lobe and cingulate cortex, and thickening in the superior parietal gyrus in comparison with controls and PSP patients. PSP patients only showed mild thickness and volume reduction in the frontal lobe, compared to control subjects. Random Forest algorithm distinguished iNPH patients from controls with AUC of 0.96 and from PSP patients with AUC of 0.95, while a lower performance (AUC 0.76) was reached in distinguishing PSP from controls., Conclusion: This study demonstrated a more severe and widespread cortical involvement in iNPH than in PSP, possibly due to the marked lateral ventricular enlargement which characterizes iNPH. A machine learning model using thickness and volumetric data led to accurate differentiation between iNPH and PSP patients, which may help clinicians in the differential diagnosis and in the selection of patients for shunt procedures., Competing Interests: Declaration of competing interest None., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Introduction: We investigated the imaging counterpart of two functional domains (ocular motor dysfunction and postural instability) in progressive supranuclear palsy (PSP) patients classified according to the new clinical diagnostic criteria., Methods: Forty-eight patients with probable PSP-Richardson's syndrome (PSP-RS), 30 with probable PSP-parkinsonism (PSP-P), 37 with Parkinson's disease (PD), and 38 controls were enrolled. For each functional domain, PSP patients were stratified by two certainty levels: vertical supranuclear gaze palsy (O1) and slowness of vertical saccades (O2) for ocular motor dysfunction; early unprovoked falls and tendency to fall on the pull-test for postural instability. Voxel-based morphometry (VBM), whole-brain fractional anisotropy (FA) and MR planimetric measurements were analysed and compared across patient groups., Results: O1 was present in 64%, and O2 in 36% of all PSP patients. All PSP-RS patients showed early unprovoked falls. TBSS whole-brain analysis revealed that superior cerebellar peduncles (SCPs) were the only structures with significantly lower FA values in PSP-RS compared with PSP-P patients. PSP/O1 patients had lower FA values in midbrain than PSP/O2 patients. By contrast, VBM revealed no differences in grey matter volume between PSP patient groups. MR Planimetric measurements confirmed atrophy of midbrain and SCPs, in line with DTI findings., Conclusions: Our study demonstrates that SCPs were significantly more damaged in patients with PSP-RS in comparison with PSP-P patients, thus suggesting the role of SCPs in developing postural instability. Midbrain damage was less severe in O2 than in O1 patients, suggesting that the degree of vertical ocular dysfunction reflects the severity of midbrain atrophy., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Introduction: Several structural and functional neuroimaging studies have shown that the Supplementary Motor Area (SMA) is affected by tau pathology in patients with Progressive Supranuclear Palsy (PSP). The aim of the study was to investigate the biochemical profile of SMA in PSP patients, using proton magnetic resonance spectroscopy ( 1 H-MRS)., Methods: Sixteen PSP patients and 18 healthy controls participated in this study. 1 H-MRS was performed by using a Point RESolving Spectroscopy (PRESS) single-voxel sequence implemented on a 3-T scanner. A voxel of 25 × 25 × 15 mm involving the right and left SMA was acquired in all subjects. Peak areas of N-acetyl-aspartate + N-acetyl-aspartyl-glutamate (NAA), creatine with phosphocreatine (Cr), glycerophosphocholine + phosphocholine (Cho), glutamate + glutamine (Glx), glutathione (GSH), myo-Inositol (mI) and Scyllo-Inositol (Scyllo) were calculated using a version 6.3-1K of the fitting program LCModel. Comparative analysis was performed on both absolute concentrations and ratio values relative to Cr., Results: PSP patients showed a significant decrease in Scyllo concentration and Scyllo/Cr ratio values in SMA, compared to controls, whereas no difference between groups was found for the other ratio values. Of note, the attention and working memory functions were positively related to Scyllo and Scyllo/Cr values in PSP patients., Conclusions: Our study demonstrates that Scyllo and Scyllo/Cr were significantly reduced in the SMA of PSP patients. Because Scyllo seems to be able to protect against formation of toxic fibrils of amyloid-beta fragments and tau oligomers deposition, these preliminary findings may open new perspectives to investigate Scyllo as a new potential disease-modifying therapy for PSP., (Copyright © 2018. Published by Elsevier Ltd.)

Introduction: Differentiating clinically progressive supranuclear palsy-parkinsonism (PSP-P) from Parkinson's disease (PD) may be challenging, especially in the absence of vertical supranuclear gaze palsy (VSGP). The Magnetic Resonance Parkinsonism Index (MRPI) has been reported to accurately distinguish between PSP and PD, yet few data exist on the usefulness of this biomarker for the differentiation of PSP-P from PD., Methods: Thirty-four patients with PSP-P, 46 with PSP-Richardson's syndrome (PSP-RS), 53 with PD, and 53 controls were enrolled. New consensus criteria for the clinical diagnosis of PSP were used as the reference standard. The MRPI, and a new index termed MRPI 2.0 including the measurement of the third ventricle width (MRPI multiplied by third ventricle width/frontal horns width ratio), were calculated on T1-weighted MR images., Results: The MRPI differentiated patients with PSP-P from those with PD with sensitivity and specificity of 73.5% and 98.1%, respectively, while the MRPI 2.0 showed higher sensitivity (100%) and similar specificity (94.3%) in differentiating between these two groups. Both biomarkers showed excellent performance in differentiating PSP-P patients with VSGP from those with PD, but the MRPI 2.0 was much more accurate (95.8%) than MRPI in differentiating PSP-P patients with slowness of vertical saccades from PD patients., Conclusion: The MRPI 2.0 accurately differentiated PSP-P patients from those with PD. This new index was more powerful than MRPI in differentiating PSP patients in the early stage of the disease with slowness of vertical saccades from patients with PD, thus helping clinicians to consolidate the diagnosis based on clinical features, in vivo., (Copyright © 2018. Published by Elsevier Ltd.)

Objective: Essential Tremor with resting tremor (rET) is a debated and poorly understood clinical phenotype. Converging evidences show that neurodegeneration of the cerebellum underlies the pathophysiology of ET, but it is not known if cerebellar changes also occurs in patients with rET. The aim of our study was to evaluate cerebellar microstructure in patients with ET with- (rET) and without resting tremor (ETwr) in comparison to healthy controls by MR Diffusion Tensor Imaging (DTI)., Methods: We studied 67 patients with ET (rET: 29 and ETwr: 38) and 39 age-matched healthy controls (HC). DTI was performed to measure fractional anisotropy (FA) and mean diffusivity (MD) of white and grey matter (WM, GM) in the entire cerebellum and in right and left cerebellar hemispheres., Results: MD was significantly higher in the cerebellar GM of ET total group (10.39 ± 0.87) in comparison with HC (9.90 ± 0.71) (p = 0.0027). Interestingly, MD was significantly different when ETwr (10.48 ± 0.77) were compared with HC (p = 0.0017), whereas a trend toward significance were found between rET (10.29 ± 0.99) and HC (p = 0.067). No differences among groups were found in MD of cerebellar WM and in FA values neither in the WM nor in the GM., Conclusion: Our results demonstrate the presence of microstructural changes in the cerebellum of patients with ET. It is noteworthy that rET showed intermediate values compared to HC and ETwr, suggesting that rET shares part of the pathophysiological mechanisms of ETwr, but cerebellar involvement seems do not fully account for rET. In addition to the cerebellar loops, other networks may play a role in rET pathophysiology., (Copyright © 2016 Elsevier Ltd. All rights reserved.)