Early diagnosis of mild cognitive impairment and Alzheimer's with event-related potentials and event-related desynchronization in N-back working memory tasks.

•In this study we performed a thorough investigation on the use of event-related potentials (ERP) and event-related (de)synchronization (ERD/ERS) for early Alzheimer’s disease (AD) diagnosis.•We compared behavioral results (reaction time and accuracy), ERP and ERD/ERS responses when healthy elderly (HE) controls, Mild Cognitive Impairment (MCI) and mild AD patients were performing a three-level N-Back working memory task.•Our most important finding was that ERD/ERS analyses have revealed themselves more valuable than ERP, since they showed significant differences in all three group comparisons: HE vs. MCI, HE vs. AD, and MCI vs. AD.