ObjectivesTo explore the role of the available midbrain-based MRI morphometric assessments in (1) differentiating among progressive supranuclear palsy (PSP) subtypes (PSP Richardson’s syndrome (PSP-RS), PSP with predominant parkinsonism (PSP-P) and the other variant syndromes of PSP (vPSP)), and (2) supporting the diagnosis of PSP subtypes compared with Parkinson’s disease (PD) and healthy controls (HC).MethodsSeventy-eight patients with PSP (38 PSP-RS, 21 PSP-P and 19 vPSP), 35 PD and 38 HC were included in the present analysis. Available midbrain-based MRI morphometric assessments were calculated for all participants.ResultsCurrent MRI midbrain-based assessments do not display an adequate sensitivity and specificity profile in differentiating PSP subtypes. On the other hand, we confirmed MR Parkinsonism Index (MRPI) and pons area to midbrain area ratio (P/M) have adequate diagnostic value to support PSP-RS clinical diagnosis compared with both PD and HC, but low sensitivity and specificity profile in differentiating PSP-P from PD as well as from HC. The same measures show acceptable sensitivity and specificity profile in supporting clinical diagnosis of vPSP versus HC but not versus PD. Similar findings were detected for the newer MRPI and P/M versions.ConclusionsFurther studies are warranted to identify neuroimaging biomarkers supporting the clinical phenotypic categorisation of patients with PSP. MRPI and P/M have diagnostic value in supporting the clinical diagnosis of PSP-RS.Classification of evidenceThis study provides class III evidence that available MRI midbrain-based assessments do not have diagnostic value in differentiating the Movement Disorder Society PSP subtypes.

ObjectiveThe aim of this study was to perform the first resting‐state functional MRI (RS‐fMRI) analysis in Friedreich's ataxia (FRDA) patients to assess possible brain functional connectivity (FC) differences in these patients, and test their correlations with neuropsychological performances.MethodsIn total, 24 FRDA patients (M/F: 15/9, mean age 31.3 ± 15.0) and 24 healthy controls (HC; M/F: 15/9, mean age 30.7 ± 15.5) were enrolled in this cross‐sectional study. All patients underwent a thorough neuropsychological battery, investigating different cognitive domains. RS‐fMRI data were analyzed using a seed‐based approach, probing the FC of cortical areas potentially referable to specific executive and cognitive functions compromised in FRDA.ResultsCompared to HC, FRDA patients showed overall worse neuropsychological scores in several domains, including global cognitive assessment, spatial memory, visuoperception and visuospatial functions, and executive functions. Analysis of RS‐fMRI data showed a higher FC in FRDA patients compared to HC between paracingulate gyri and the medial frontal gryrus, between the superior frontal gyrus and bilateral angular gyri, and between the middle temporal gyrus and the cingulate gyrus, with a reduced FC between the medial frontal gryrus and the cerebellum.InterpretationWe found a reduction in FC between frontal areas and the contralateral cerebellar cortex in FRDA, in line with the known alteration in cerebello‐cortical pathway in this condition. On the other hand, a higher FC between different cortical areas was shown, possibly reflecting a compensatory phenomenon. These results, in conjunction with clinical findings, may shed new light on the pattern of supratentorial and infratentorial involvement, and on dynamics of brain plasticity in this disease.

Friedreich's ataxia (FRDA) is an autosomal recessive disease presenting with ataxia, corticospinal signs, peripheral neuropathy, and cardiac abnormalities. Little effort has been made to understand the psychological and emotional burden of the disease. The aim of our study was to measure patients' ability to recognize emotions using visual and non-verbal auditory hints, and to correlate this ability with psychological, neuropsychological, and neurological variables. We included 20 patients with FRDA, and 20 age, sex, and education matched healthy controls (HC). We measured emotion recognition using the Geneva Emotion Recognition Test (GERT). Neuropsychological status was assessed measuring memory, executive functions, and prosopagnosia. Psychological tests were Patient Health Questionnaire-9 (PHQ-9), State Trait Anxiety Inventory-state/-trait (STAI-S/-T), and Structured Clinical Interview for DSM Disorders II. FRDA patients scored worse at the global assessment and showed impaired immediate visuospatial memory and executive functions. Patients presented lower STAI-S scores, and similar scores at the STAI-T, and PHQ-9 as compared to HC. Three patients were identified with personality disorders. Emotion recognition was impaired in FRDA with 29% reduction at the total GERT score (95% CI - 44.8%, - 12.6%; p < 0.001; Cohen's d = 1.2). Variables associated with poor GERT scores were the 10/36 spatial recall test, the Ray Auditory Verbal Learning Test, the Montreal Cognitive Assessment, and the STAI-T (R = 0.906; p < 0.001). FRDA patients have impaired emotion recognition that may be secondary to neuropsychological impairment. Depression and anxiety were not higher in FRDA as compared to HC and should not be considered as part of the disease.

For several years different types of nanoparticles have been considered and studied as potential friction modifying lubricant additives. Some nanoparticles can reduce the friction coefficient by 30-70%, depending on the base oil and the experimental conditions. In the present study, an experimental analysis on tribological properties of inorganic fullerene-like metal dichalcogenides was performed in comparison with MoS 2 2H layered structures. Tribological tests were carried out on a pin on disc tribometer in ambient air. Several contact conditions are analysed in order to realise boundary and mixed lubrication regimes. The experimental study was performed on a mineral base oil, and particle concentration effects were analysed. Antifriction properties were evaluated by measuring the friction coefficient and are presented as generalised Stribeck diagrams. Inorganic fullerene-like WS 2 and MoS 2 nanoparticles present interesting friction reduction properties when tested in boundary and mixed lubrication.

Background Available evidence reports conflicting data on retinal thickness in progressive supranuclear palsy (PSP). In studies including healthy controls, PSP showed either the thinning of the retinal nerve fiber layer, macular ganglion cell, inner nuclear, or outer retina layer. Objectives The goals of the present study were to describe retinal layer thickness in a large cohort of PSP compared to healthy controls and in PSP phenotypes using spectral-domain optical coherence tomography (SD-OCT). The additional objective was to verify the relationship between retinal layers thickness and clinical variables in PSP. Methods Using a cross-sectional design, we examined retinal structure in 27 PSP patients and 27 controls using standard SD-OCT. Motor and cognitive impairment in PSP was rated with the PSP rating scale and the Montreal Cognitive Assessment battery (MoCA), respectively. Eyes with poor image quality or confounding diseases were excluded. SD-OCT measures of PSP and controls were compared with parametric testing, and correlations between retinal layer thicknesses and disease severity were evaluated. Results PSP showed significant thinning of the inner retinal layer (IRL), ganglion cell layer (GCL), inner plexiform layer (IPL), and the outer plexiform layer (OPL) compared to healthy controls. PSP phenotypes showed similar retinal layer thicknesses. Retinal layer thickness correlated with MoCA visuospatial subscore (p < 0.001). Conclusions We demonstrated PSP patients disclosed thinner IRL, GCL, IPL, and OPL compared to healthy controls. Furthermore, we found a significant correlation between visuospatial abilities and retinal layers suggesting the existence of a mutual relationship between posterior cognitive function and retinal structure.