Predicting conversion of patients with Mild Cognitive Impairment to Alzheimer's disease using bedside cognitive

Abby Clarke1, Calvin Ashe1, Jill Jenkinson1

  • 1Department of Psychology, Maynooth University, Maynooth, Ireland.

Abstract

Insights

The Alzheimer's Disease Assessment Scale-Cognitive (ADAS-13) best predicts progression from Mild Cognitive Impairment (MCI) to Alzheimer's disease (AD) compared to other cognitive tests and biomarkers. This cognitive test offers a simpler, more effective method for identifying at-risk patients.

Area of Science:

  • Neurology
  • Cognitive Science
  • Biomarker Research

Background:

  • Mild Cognitive Impairment (MCI) is a precursor to dementia, but not all individuals with MCI progress to Alzheimer's disease (AD).
  • Predicting conversion from MCI to AD is crucial for timely intervention and clinical trial enrollment.
  • Current cognitive tests have limitations in accurately predicting AD progression.

Purpose of the Study:

  • To evaluate the predictive accuracy of different cognitive tests for conversion from MCI to AD.
  • To compare the predictive power of cognitive tests against established AD biomarkers (Amyloid-beta and phospho-tau).

Main Methods:

  • Utilized data from 325 MCI patients in the Alzheimer's Disease Neuroimaging Initiative (ADNI-2) dataset, followed for 5 years.
  • Administered baseline cognitive tests: Mini Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), and Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog 13).
  • Assessed conversion to AD, with 25% (n=83) progressing within 5 years.

Main Results:

  • Individuals progressing to AD showed significantly lower MMSE and MoCA scores and higher ADAS-13 scores at baseline.
  • The ADAS-13 demonstrated the highest predictability for MCI to AD conversion (Adjusted Odds Ratio [AOR] = 3.91), outperforming Amyloid-beta (AOR = 1.99) and phospho-tau (AOR = 1.72).
  • Specific ADAS-13 sub-items, including delayed recall and word recognition, were particularly indicative of conversion.

Conclusions:

  • The ADAS-13 is a highly effective cognitive test for predicting conversion from MCI to AD.
  • ADAS-13 offers a more accessible and clinically relevant predictive tool than current biomarkers.
  • Routine use of ADAS-13 can aid clinicians in identifying MCI patients at higher risk of progressing to Alzheimer's disease.

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