Perceptual and response interference in Alzheimer's disease and mild cognitive impairment

Abstract

Objectives: The ability to resolve conflicts is indispensable to the function of daily life and decreases with cognitive decline. We hypothesized that subjects with different levels of cognitive impairment exhibit different conflict resolution performances and may be susceptible to interference effects at different stages.

Methods: Sixteen normal controls (NC), 15 mild cognitive impairment (MCI) and seven Alzheimer's disease (AD) patients were recruited to perform in a modified Eriksen flanker task.

Results: We observed that the AD and MCI patients exhibited smaller accuracy rate and longer response time compared to NC subjects. Longer N2 and P300 latencies were observed in the AD group. Furthermore, the MCI group showed a longer latency than the NC group in the P300 latency. The magnitude of the perceptual and response interference effects was larger in the AD group than the other groups, and the MCI group significantly differed from the NC group at the perceptual level.

Conclusion: The ability to resolve conflict decreased with impaired cognition and the perceptual and response interference effects may be useful in distinguishing MCI and AD.

Significance: The perceptual or response interference effect may potentially be employed as a useful non-invasive probe for the clinical diagnosis of MCI and AD.

Keywords: Alzheimer’s disease; Event-related potential; Flanker task; Perceptual processes; Response processes.