Isolated, Subtle Neurological Abnormalities in Mild Cognitive Impairment Types

Area of Science:

• Neurology
• Neuroimaging
• Geriatrics

Background:

• Isolated, subtle neurological abnormalities (ISNA) are frequently observed in aging.
• These abnormalities are associated with cerebral small vessel disease (SVD) and subcortical atrophy in healthy aging individuals.

Purpose of the Study:

• To determine the prevalence of ISNA across different types of mild cognitive impairment (MCI).
• To examine the relationship between ISNA and specific neuroimaging markers (white matter hyperintensities, lacunes, caudate atrophy, ventricular enlargement) in each MCI subtype.

Main Methods:

• Analysis of brain MRI scans from 1250 subjects with various MCI types.
• Assessment of white matter hyperintensities (WMH), lacunes, caudate atrophy (bicaudate ratio - BCr), and ventricular enlargement (lateral ventricles to brain ratio - LVBr).
• Evaluation of ISNA using neurological examination and Parkinson's disease rating scales; Apolipoprotein E (APOE) genotyping performed.

Main Results:

• ISNA prevalence increases with age and is present in all MCI types, especially in multiple-domain MCI.
• ISNA is associated with carrying the APOE ε4 allele.
• Significant associations were found between ISNA and WMH, lacunes, BCr, and LVBr.

Conclusions:

• Both cortical and subcortical vascular and atrophic processes contribute to ISNA.
• Prospective studies are required to clarify the role of ISNA in the progression from MCI to dementia.