Possibility of MEG as an Early Diagnosis Tool for Alzheimer's Disease: A Study of Event Related Field in Missing Stimulus Paradigm

Abstract

We are investigating a diagnosis to find Alzheimer's disease (AD), which is a kind of dementia and one of the most prominent neurodegenerative disorders, using a magnetoencephalography (MEG). MEG is one of non-invasive technique to investigate the brain function by using an array of superconducting quantum interference device (SQUID) sensors arranged around the head. In this study, we observed the event-related field in 'missing stimulus' paradigm. The subjects were presented short beep tones with a certain interval. Some tones were omitted randomly from the sequence and this omission was called 'tone-omitted event'. We focused on the specific magnetic field component induced by the tone-omitted event. 32 patients with early AD and 32 age-matched controls were examined by 160-ch whole-head MEG system. The MEG signals related to the tone-omitted events were collected from each subject. The amplitude of the averaged waveform in the AD group was significantly smaller than that in the control group. This result suggests that MEG is useful for AD diagnosis.