Extracranial carotid artery stenosis (ECAS) due to the presence of atherosclerotic plaque is a well-known risk factor for stroke. Several structural imaging studies have investigated the effect of ECAS on the brain, focusing on structural damage (in particular cerebral small vessel disease) and on the rearrangement of the cerebral circulation. For example, it is known from the literature an association between carotid stenosis and cerebral small vessel disease, and it is also noted that a series of compensatory mechanisms are activated by the cerebrovascular system in order to overcome the cerebral hypoperfusion that is induced by the ECAS. Several neurocognitive studies have also investigated the association of ECAS with cognitive deficits. While the evidence tends to favor a direct association between ECAS and cognition, the actual relationship remains controversial. In the last decade, various resting-state functional connectivity (rs-fc) magnetic resonance (MR) studies have tried to elucidate the "in vivo" mechanisms underlying the cognitive impairment observed in these patients. Although these studies have been performed on small cohorts of patients without standardized protocols, it is plausible that in the future, such studies will help find early stage markers of cognitive impairment. This could permit an extension of indications for revascularization for the treatment of cognitive impairment in selected patients. The aim of this narrative review is to discuss the current knowledge on the effects of ECAS on brain and cognition by analyzing the main evidence from animal and clinical studies, with a special focus on rs-fc MR studies.

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Purpose The study aims to evaluate the mid-term effects of carotid endarterectomy (CEA) on cognition and resting-state functional magnetic resonance imaging (rs-fMRI) using the Amplitude of Low Frequency Fluctuations (ALFF) technique. Methods In this observational study, patients eligible for CEA were prospectively included. On the same day, within 1 week of the CEA procedure performed and 12 months after the CEA procedure, all patients underwent (i) an MRI examination for rs-fMRI analysis and (ii) a cognitive evaluation using the Italian version of the Mini-Mental State Examination (MMSE) corrected for age and schooling. Pre-CEA and post-CEA MMSE scores were evaluated using paired sample t-tests, adopting a p-value < 0.05 as statistical threshold. The ALFF technique was used for analyzing the differences between pre-CEA and post-CEA rs-fMRI scans in terms of regional neural activation. This was accomplished by applying non-parametric statistics based on randomization/permutation for cluster-level inferences, adopting a cluster-mass p-value corrected for false discovery < 0.05 for cluster threshold, and a p-uncorrected < 0.01 for the voxel threshold. Results Twenty asymptomatic patients were enrolled. The mean MMSE score resulted improved following CEA procedure (p-value = 0.001). The ALFF analysis identified a single cluster of 6260 voxels of increased regional neural activity following CEA, and no cluster of reduced activity. The majority of voxels covered the right precentral gyrus, the right middle frontal gyrus, and the anterior division of the cingulate gyrus. Conclusion Mid-term cognitive improvements observed after CEA are associated to increased regional neural activity of several cerebral regions.

Sclerosteosis is a rare genetic disorder of bone modelling, similar to, but distinct from, van Buchem disease; it has been described almost exclusively in Afrikaners of South Africa, a white population of Dutch ancestry. Isolated cases have been reported in a girl in Japan, a boy in Spain, and in multiracial families in Brazil and USA. Here we report a case of sclerosteosis in a black man born in Senegal. He presented with the full features of the disease: tall stature; syndactyly; nail dysplasia; massive sclerosis of the long tubular bones, the ribs, the pelvis and the skull; multiple cranial nerve involvement: optic atrophy, facial palsy and trigeminal neuralgia. Radiologic examination, visual and brainstem auditory evoked potentials, computerized tomography and magnetic resonance imaging of the skull were performed. This seems to be the first case of the disease in a black African individual, with no known relationship with Dutch ancestry.

White matter hyperintensities (WMH) are common findings that can be found in physiological ageing. Several studies suggest that the disruption of white matter tracts included in WMH could induce abnormal functioning of the respective linked cortical structures, with consequent repercussion on the cerebral functions, included the cognitive sphere. In this cross‐sectional research, we analysed the effects of the total WMH burden (tWMHb) on resting‐state functional magnetic resonance imaging (rs‐fMRI) and cognition. Functional and structural MR data, as well as the scores of the trail making test subtests A (TMT‐A) and B (TMT‐B) of 75 healthy patients, were extracted from the public available Leipzig Study for Mind–Body–Emotion Interactions dataset. tWMHb was extracted from structural data. Spearman's correlation analyses were made for investigating correlations between WMHb and the scores of the cognitive tests. The fractional amplitude of low‐frequency fluctuations (fALFF) method was applied for analysing the rs‐fMRI data, adopting a multiple regression model for studying the effects of tWMHb on brain activity. Three different subanalyses were conducted using different statistical methods. We observed statistically significant correlations between WMHb and the scores of the cognitive tests. The fALFF analysis revealed that tWMHb is associated with the reduction of regional neural activity of several brain areas (in particular the prefrontal cortex, precuneus and cerebellar crus I/II). We conclude that our findings clarify better the relationships between WMH and cognitive impairment, evidencing that tWMHb is associated with impairments of the neurocognitive function in healthy subjects by inducing a diffuse reduction of the neural activity.