Magnetoencephalographic parietal δ dipole density in mild cognitive impairment: Preliminary results of a method to estimate the risk of developing Alzheimer disease

Abstract

Background: Subjects with mild cognitive impairment (MCI) are at a higher risk of experiencing Alzheimer disease (AD). Magnetoencephalographic temporoparietal dipole densities of low-frequency activity are good predictors of individuals' cognitive status, and might be a useful tool to investigate the conversion from MCI to AD.

Objective: To investigate the role of low-frequency dipole densities as predictors of the risk of developing AD.

Design: Whole-head magnetoencephalographic recordings were obtained from 19 probable AD patients, 17 MCI patients, and 17 healthy control subjects. The generators of focal magnetic slow waves were located using a single moving dipole model.

Results: Left parietal δ dipole density permitted a reliable classification of AD and MCI patients. The MCI patients were divided into 2 groups based on the median left parietal δ dipole density, and were followed up for 2 years. The estimated relative risk of conversion to AD was increased by 350% in those MCI patients with high left parietal δ dipole density scores.

Conclusions: Results confirmed the important role of parietal δ dipole density in the evaluation of AD and MCI. A magnetoencephalographic-based assessment of AD and MCI patients might be considered a useful clinical test in the near future.