Brain oscillatory responses to an auditory-verbal working memory task in mild cognitive impairment and Alzheimer's disease

Mira Karrasch, Matti Laine, JO Rinne, P Rapinoja, E Sinerva, CM Krause

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    We report preliminary findings oil EEG oscillatory correlates of working memory in mild cognitive impairment (MCI) and Alzheimer's disease (AD). Event-related desynchronization (ERD) and synchronization (ERS) of the 1-20 Hz EEG frequencies were studied using wavelet transforms in elderly controls, MCI patients and mild probable AD patients performing an auditory-verbal Sternberg memory task. Behaviourally, the AD patients made more errors than the controls and the MCI group. Statistically significant differences during the encoding of the memory set were found between the controls and the MCI group, such that the latter group showed ERD in the similar to 10-20 Hz frequencies. The findings may reflect different.. compensatory encoding strategies in MCI. During retrieval, the most obvious differences were observed between the controls and the AD group: the ERD in the similar to 7-17 Hz frequencies was absent in the AD group particularly in anterior and left temporal electrode locations. This finding might indicate that AD is associated with deficient lexical-semantic processing during the retrieval phase in working memory tasks. Future studies with larger patient groups are needed to establish the diagnostic value of ERD/ERS patterns in MCI and AD. (c) 2005 Elsevier B.V. All rights reserved.
    Original languageUndefined/Unknown
    Pages (from-to)168–178
    Number of pages11
    JournalInternational Journal of Psychophysiology
    Issue number2
    Publication statusPublished - 2006
    MoE publication typeA1 Journal article-refereed


    • 1-20 Hz
    • Alzheimer's disease
    • EEG
    • event-related desynchronization
    • event-related synchronization
    • memory
    • mild cognitive impairment

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