Frontiers in Neurology (May 2014)

The sub-classification of amnestic mild cognitive impairment using MRI-based cortical thickness measures

  • Pradeep Redddy eRaamana,
  • Wei eWen,
  • Wei eWen,
  • Nicole A Kochan,
  • Nicole A Kochan,
  • Henry eBrodaty,
  • Henry eBrodaty,
  • Perminder S Sachdev,
  • Perminder S Sachdev,
  • Lei eWang,
  • Mirza Faisal eBeg

DOI
https://doi.org/10.3389/fneur.2014.00076
Journal volume & issue
Vol. 5

Abstract

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Background: Amnestic Mild cognitive impairment (aMCI) is considered to be the transitional stage between healthy aging and Alzheimer’s disease (AD). Moreover, aMCI individuals with additional impairment in one or more non-memory cognitive domains are at higher risk of conversion to AD. Hence accurate identification of the subtypes of aMCI would enable earlier detection of individuals progressing to AD. Methods: We examine the group differences in cortical thickness between single-domain and multiple-domain subtypes of aMCI, and as well as with respect to age-matched controls in a well-balanced cohort from the Sydney Memory and Ageing Study. In addition, we assess the diagnostic value of cortical thickness in the sub-classification of aMCI as well as from normal controls using support vector machine (SVM) classifier, using a novel cross-validation technique that can handle class-imbalance. Results: This study revealed an increased, as well as a wider spread, of cortical thinning in multiple-domain aMCI compared to single-domain aMCI. The best performances of the classifier for the pairs 1) single domain aMCI and normal controls, 2) multiple domain aMCI and normal controls and 3) single and multiple domain aMCI were AUC=0.52, 0.66 and 0.54 respectively. The accuracy of the classifier for the three pairs was just over 50% exhibiting low specificity (44- 60%) and similar sensitivity (53-68%). Conclusions: Analysis of group differences added evidence to the hypothesis that multiple-domain aMCI is a later stage of AD compared to single-domain aMCI. The classification results show that discrimination among single, multiple domain subtypes of aMCI and normal controls is limited using baseline cortical thickness measures.

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