Isolated Subtle Neurological Abnormalities in Mild Cognitive Impairment Types

Background: Isolated, subtle neurological abnormalities (ISNA) are commonly seen in aging and have been related to cerebral small vessel disease (SVD) and subcortical atrophy in neurologically and cognitively healthy aging subjects. Objective: To investigate the frequency of ISNA in different mild cognitive impairment (MCI) types and to evaluate for each MCI type, the crosssectional relation between ISNA and white matter hyperintensities (WMH), lacunes, caudate atrophy, and ventricular enlargement. Methods: One thousand two hundred fifty subjects with different MCI types were included in the analysis and underwent brain magnetic resonance imaging. WMHs were assessed through two visual rating scales. Lacunes were also rated. Atrophy of the caudate nuclei and ventricular enlargement were assessed through the bicaudate ratio (BCr) and the lateral ventricles to brain ratio (LVBr), respectively. Apolipoprotein E (APOE) genotypes were also assessed. The routine neurological examination was used to evaluate ISNAs that were clustered as central-based signs, cerebellar-based signs, and primitive reflexes. The items of Part-III of the Unified Parkinson’s Disease Rating Scale were used to evaluate ISNAs that were clustered as mild parkinsonian signs. Associations of ISNAs with imaging findings were determined through logistic regression analysis. Results: The ISNAs increase with the age and are present in all MCI types, particularly in those multiple domains, and carrying the APOE ϵ4 allele, and are associated with WMH, lacunes, BCr, and LVBr. Conclusion: This study demonstrates that cortical and subcortical vascular and atrophic processes contribute to ISNAs. Long prospective population-based studies are needed to disentangle the role of ISNAs in the conversion from MCI to dementia

Vascular Risk Factors, Vascular Diseases, and Imaging Findings in a Hospital-based Cohort of Mild Cognitive Impairment Types

Background: Mild Cognitive Impairment (MCI) is a transitional state between normal cognition and dementia.Objective: The aim of this study is to investigate the role of vascular risk factors, vascular diseases, cerebrovascular disease and brain atrophy in a large hospital-based cohort of MCI types including 471 amnestic MCI (a-MCI), 693 amnestic MCI multiple domain (a-MCImd), 322 single non-memory MCI (snm-MCI), and 202 non amnestic MCI multiple domain (na-MCImd). For comparison, 1,005 neurologically and cognitively healthy subjects were also evaluated.Method: Several vascular risk factors and vascular diseases were assessed. All participants underwent neurological, neuropsychological and behavioural assessments as well as carotid ultrasonography and standard brain MRI. Multinomial logistic regression models on the MCI cohort with the NCH group and a-MCI type as reference categories were used to assess the effects of the variables evaluated on the estimated probability of one of the four MCI types.Results: This study demonstrates that cerebrovascular disease contributes substantially to the risk of non-memory MCI types and a-MCImd type, and that brain atrophy is present in all MCI types and is greater in multiple domain types particularly in the na-MCI type.Conclusion: Improving detection and control of cerebrovascular disease in aging individuals should be mandatory. Since the incidence of MCI and dementia will be expected to rise because of the progressive life expectancy, a better management of cerebrovascular disease could indeed prevent or delay the onset of MCI, or could delay progression of MCI to dementia