Correlation of auditory event-related potentials and magnetic resonance spectroscopy measures in mild cognitive impairment

Abstract

This study was aimed to examine the changes in auditory event-related potentials (AERPs) and their relationship with brain metabolic changes in mild cognitive impairment (MCI). 34 MCI patients and 34 healthy elderly controls were subjected to auditory stimulus oddball task, and then post-stimulus potentials (P50, N100, P200, N200, and P300) were obtained, levels of N-acetylaspartate (NAA), creatine (Cr) and the ratio of NAA/Cr were measured by proton magnetic resonance spectroscopy (1H-MRS) in left frontal, left temporal and right parietal cortex. Compared with the control group, the MCI group had significantly increased P50 amplitudes and P300 latency, and the NAA/Cr was abnormal. Linear progression analysis revealed a strong negative correlation between P50 amplitudes and NAA/Cr in left frontal cortex, and negative correlation between P300 latency and NAA/Cr in left frontal and left temporal, as well as correlation of AERP components and MRS metabolites with clinical scores of cognitive tests. These findings suggest that metabolic abnormalities of different brain regions may reflect the changes of underlying brain activities that are instrumental in the MCI. Therefore AERPs and MRS measurements may offer a mean to track changes of brain activities associated with functional changes, and to assess early cognitive impairment in MCI.