Brain changes have been reported in the first weeks after SARS-CoV-2 infection. However, limited literature exists about brain alterations in post-COVID syndrome, a condition increasingly associated with cognitive impairment. The present study aimed to evaluate brain functional and structural alterations in patients with post-COVID syndrome, and assess whether these brain alterations were related to cognitive dysfunction. Eighty-six patients with post-COVID syndrome and 36 healthy controls were recruited and underwent neuroimaging acquisition and a comprehensive neuropsychological assessment. Cognitive and neuroimaging examinations were performed 11 months after the first symptoms of SARS-CoV-2. Whole-brain functional connectivity analysis was performed. Voxel-based morphometry was performed to evaluate grey matter volume, and diffusion tensor imaging was carried out to analyse white-matter alterations. Correlations between cognition and brain changes were conducted and Bonferroni corrected. Post-COVID syndrome patients presented with functional connectivity changes, characterized by hypoconnectivity between left and right parahippocampal areas, and between bilateral orbitofrontal and cerebellar areas compared to controls. These alterations were accompanied by reduced grey matter volume in cortical, limbic and cerebellar areas, and alterations in white matter axial and mean diffusivity. Grey matter volume loss showed significant associations with cognitive dysfunction. These cognitive and brain alterations were more pronounced in hospitalized patients compared to non-hospitalized patients. No associations with vaccination status were found. The present study shows persistent structural and functional brain abnormalities 11 months after the acute infection. These changes are associated with cognitive dysfunction and contribute to a better understanding of the pathophysiology of the post-COVID syndrome.

Background: Our aim was to evaluate and compare the diagnostic properties of 5 screening tests for the diagnosis of mild Alzheimer disease (AD). Methods: We conducted a prospective and cross-sectional study of 92 patients with mild AD and of 68 healthy controls from our Department of Neurology. The diagnostic properties of the following tests were compared: Mini-Mental State Examination (MMSE), Addenbrooke's Cognitive Examination III (ACE-III), Memory Impairment Screen (MIS), Montreal Cognitive Assessment (MoCA), and Rowland Universal Dementia Assessment Scale (RUDAS). Results: All tests yielded high diagnostic accuracy, with the ACE-III achieving the best diagnostic properties. The area under the curve was 0.897 for the ACE-III, 0.889 for the RUDAS, 0.874 for the MMSE, 0.866 for the MIS, and 0.856 for the MoCA. The Mini-ACE score from the ACE-III showed the highest diagnostic capacity (area under the curve 0.939). Memory scores of the ACE-III and of the RUDAS showed a better diagnostic accuracy than those of the MMSE and of the MoCA. All tests, especially the ACE-III, conveyed a higher diagnostic accuracy in patients with full primary education than in the less educated group. Implementing normative data improved the diagnostic accuracy of the ACE-III but not that of the other tests. Conclusions: The ACE-III achieved the highest diagnostic accuracy. This better discrimination was more evident in the more educated group.

Addenbrooke's Cognitive Examination III (ACE-III) is a screening test that was recently validated for diagnosing dementia. Since it assesses attention, language, memory, fluency, and visuospatial function separately, it may also be useful for general neuropsychological assessments. The aim of this study was to analyze the tool's ability to detect early stages of Alzheimer's disease and to examine the correlation between ACE-III scores and scores on standardized neuropsychological tests. Our study included 200 participants categorized as follows: 25 healthy controls, 48 individuals with subjective memory complaints, 47 patients with amnestic mild cognitive impairment and 47 mild Alzheimer's disease, and 33 patients with other neurodegenerative diseases. The ACE-III memory and language domains were highly correlated with the neuropsychological tests specific to those domains (Pearson correlation coefficient of 0.806 for total delayed recall on the Free and Cued Selective Reminding Test vs. 0.744 on the Boston Naming Test). ACE-III scores discriminated between controls and patients with amnestic mild cognitive impairment (AUC: 0.906), and between controls and patients with mild Alzheimer's disease (AUC: 0.978). Our results suggest that ACE-III is a useful neuropsychological test for assessing the cognitive domains of attention, language, memory, and visuospatial function. It also enables detection of Alzheimer's disease in early stages.