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This article is part of the supplement: International Society on Brain and Behaviour: 2nd International Congress on Brain and Behaviour

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The utility of measures of electrophysiological and information processing variability in distinguishing between normal age-related cognitive decline, Subjective Memory Complaint (SMC), Mild Cognitive Impairment (MCI), and Alzheimer's disease (AD)

Michael Hogan1*, Richard Roche2, Paul Dockree2, Ian Robertson2 and Brian Lawlor2

  • * Corresponding author: Michael Hogan

Author Affiliations

1 NUI, Galway, Ireland

2 Trinity College, Dublin, Ireland

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Annals of General Psychiatry 2006, 5(Suppl 1):S214  doi:10.1186/1744-859X-5-S1-S214

The electronic version of this article is the complete one and can be found online at:

Published:28 February 2006



Recent theoretical models of cognitive aging have implicated increased intra-individual variability as a critical marker of decline. The current study examined electrophysiological and information processing variability and memory performance in normal younger and older adults, and older adults with Subjective Memory Complaint (SMC), Mild Cognitive Impairment (MCI), and Alzheimer's Disease (AD). It was hypothesized that higher levels of variability would be indicative of age-related and disease-related memory deficits.

Materials and methods

24 young, 24 old, 21 SMCs, 15 MCIs, and 16 ADs (Mean age = 21.5, 72.8, 71.8, 76, and 77 years, respectively) were recruited with informed consent and received clinical assessment (Hogan et al., 2003), neuropsychological screening, and electrophysiological assessment while performing an implicit and explicit memory task.


Consistent with previous research, behavioural variability emerged as sensitive to age- and disease-related change. Results also indicated that amplitude variability (AmpV) of event-related potentials (ERPs) provide some additional insight into the dynamic nature of age- and disease-related memory changes.


Results are discussed in light of theoretical and applied issues in the field of cognitive aging.


  1. Hogan MJ, Swanwick GR, Kaiser J, Rowan M, Lawlor B: Memory-related EEG power and coherence reductions in mild Alzheimer's disease.

    Int J Psychophysiol 2003, 49:147-163. PubMed Abstract | Publisher Full Text OpenURL