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Intra-individual reaction time variability in aMCI: A precursor to dementia?

Tales, Andrea, Leonards, U., Bompas, Aline Elisabeth Dominique, Snowden, Robert Jefferson, Philips, M., Porter, G., Haworth, Jonathan, Wilcock, G. and Bayer, Antony 2012. Intra-individual reaction time variability in aMCI: A precursor to dementia? Journal of Alzheimer's Disease 32 (2) , pp. 457-466. 10.3233/JAD-2012-120505

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We used an exogenous target detection cueing paradigm to examine whether intra-individual reaction time variability (IIV) or phasic alerting varied significantly between patients with amnestic mild cognitive impairment (aMCI) (n = 45) and healthy older adult controls (n = 31) or between those with aMCI who, within a 2.5 year follow-up period, developed dementia (n = 13) and those who did not (n = 26). Neither IIV, nor simple reaction time, differentiated aMCI from healthy aging, indicating that raised IIV and overall response slowing are not general characteristics of aMCI. However, within the aMCI group, IIV did differentiate between those who converted to dementia and those who remained with a diagnosis of aMCI (non-converters), being significantly more variable in those who later developed dementia. Furthermore, there was no difference in IIV between non-converters and healthy controls. High IIV appears related to an increased probability that an individual with aMCI will become demented within 2.5 years, rather than to amnestic dysfunction per se. In contrast, phasic alerting performance significantly differentiated aMCI from healthy aging, but failed to discriminate those with aMCI who developed dementia from those who did not. In addition, those patients with aMCI who did not develop dementia still showed a significantly poorer phasic alerting effect compared to healthy aging. The phasic alerting abnormality in aMCI compared to healthy aging does not appear specifically related to the performance of those patients for whom aMCI represents the prodromal stages of dementia.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Cardiff University Brain Research Imaging Centre (CUBRIC)
Subjects: B Philosophy. Psychology. Religion > BF Psychology
R Medicine > RC Internal medicine > RC0321 Neuroscience. Biological psychiatry. Neuropsychiatry
Uncontrolled Keywords: Aging; dementia; mild cognitive impairment; reaction time; visual attention
Publisher: IOS Press
Last Modified: 04 Nov 2020 02:27

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