Differential cued recall memory impairment in mild cognitive impairment due to Alzheimer's disease versus Parkinson's disease

TL;DR

This study shows that memory impairment in Alzheimer's-related mild cognitive impairment is more severe than in Parkinson's-related cases, using a specific memory test.

Contribution

The study identifies distinct memory impairment profiles in Alzheimer's and Parkinson's diseases using the Memory Binding Test.

Findings

AD-aMCI showed significantly worse paired cued recall performance compared to PD-MCI, PD-NC, and controls.

The Memory Binding Test effectively differentiates AD-aMCI from controls and PD-MCI with high accuracy.

PD-MCI and PD-NC did not show significant differences in memory performance compared to controls.

Abstract

Both Alzheimer's (AD) and Parkinson's disease (PD) are often associated with memory dysfunction, but their pathophysiological underpinnings differ. The current research aimed to differentiate specific profiles of memory impairment due to AD versus PD. We used controlled learning and cued recall paradigm based on the Memory Binding Test (MBT) in ‘clinically cognitively normal’ controls (CN; n = 161), in patients with amnestic mild cognitive impairment due to AD (AD‐aMCI; n = 50) and due to PD (PD‐MCI; n = 22), and in PD with normal cognition (n = 18) as based on performance in the neuropsychological battery to prevent circularity in diagnostic decision‐making. We applied analysis of covariance (ANCOVA) and Receiver Operating Characteristic (ROC) analysis to determine between‐group differences and detection potential of the MBT. We found statistically large between‐group differences with worse memory performance in paired cued recall conditions in AD‐aMCI<PD‐MCI; AD‐aMCI<PD‐NC; AD‐aMCI<CN (p < .001 after Bonferroni correction), and to a lesser extent in PD‐MCI<CN (p = .039). However, PD‐NC did not differ from PD‐MCI, and PD‐NC did not differ from CN (p > .050). The detection potential of MBT paired cued recall for differentiating memory impairment in AD‐aMCI from CN yielded an AUC of 90% (95% CI, 85–96) and an AUC of 91% (95% CI, 81–>99) between AD‐aMCI and PD‐MCI. Associative memory and binding impairment are most pronounced in AD‐aMCI in comparison to PD‐MCI and controls. Overall, the MBT is an efficient tool for the differential diagnosis of memory impairment due to the two most common neurodegenerative diseases.

Figures