Usefulness of Discriminability and Response Bias Indices for the Evaluation of Recognition Memory in Mild Cognitive Impairment and Alzheimer Disease

Abstract

Background: Most studies examining episodic memory in Alzheimer disease (AD) have focused on patients' impaired ability to remember information. This approach provides only a partial picture of memory deficits since other factors involved are not considered. Objective: To evaluate the recognition memory performance by using a yes/no procedure to examine the effect of discriminability and response bias measures in amnestic mild cognitive impairment (a-MCI), AD dementia, and normal-aging subjects. Methods: We included 43 controls and 45 a-MCI and 51 mild AD dementia patients. Based on the proportions of correct responses (hits) and false alarms from the Rey Auditory Verbal Learning Test (RAVLT), discriminability (d′) and response bias (C) indices from signal detection theory (SDT) were calculated. Results: Results showed significant group differences for d′ (F (2) = 83.26, p < 0.001), and C (F (2) = 6.05, p = 0.00). The best predictors of group membership were delayed recall and d′ scores. The d′ measure correctly classified subjects with 82.98% sensitivity and 91.11% specificity. Conclusions: a-MCI and AD dementia subjects exhibit less discrimination accuracy and more liberal response bias than controls. Furthermore, combined indices of delayed recall and discriminability from the RAVLT are effective in defining early AD. SDT may help enhance diagnostic specificity.

Differences in Discriminability and Response Bias on Rey Auditory Verbal Learning Test Delayed Recognition in Behavioral Variant Frontotemporal Dementia and Alzheimer’s Disease

“…Response bias B" was not previously examined in bvFTD, but Russo et al (2017) report a significantly lower discriminative ability and a liberal response bias in patients with AD, which is highly similar to our findings in the AD group. The lack of a difference in response bias between bvFTD and AD found in our study appears counterintuitive, but the (slightly) liberal response bias that was present in both patients groups (but not in controls) is in line with previous findings in patients with dementia (Beth et al, 2009).…”

“…One can hypothesize that differences in memory performance in bvFTD and AD change with disease progression and accompanying atrophy of frontal and temporal brain areas. For example, it is hypothesized that frontal/dysexecutive impairment in AD increases as the disease progresses (Russo et al, 2017), which may result in a larger (liberal) response bias and a potential larger between-group difference. The mean age of the AD patients was relatively young (68.1 ± 7.2 years) with an MMSE score of 22.7 ± 4.6 indicating a substantial number of early-onset cases and a relatively mild disease severity.…”

Adding Recognition Discriminability Index to the Delayed Recall Is Useful to Predict Conversion from Mild Cognitive Impairment to Alzheimer's Disease in the Alzheimer's Disease Neuroimaging Initiative

“…Most studies simplify recognition task by only registering the number of correct identifications (hits), without the inclusion of false alarms in their interpretation. Based on the signal detection theory, a discriminability recognition index (d-prime) can be calculated including both hits and false alarms (Russo et al, 2016). In addition, d-prime has been shown to distinguish healthy older adults from those with a-MCI or mild AD.…”

Toward a Multimodal Computer-Aided Diagnostic Tool for Alzheimer’s Disease Conversion

“…A neuroimaging study conducted by Moradi et al (2017) found that the MRI-based volumetric features were suitable variables for predicted parts of the RAVLT tool using an elastic net-based linear regression model. Russo et al (2017) found that parts of the RAVLT assessment can have differences in discrimination accuracy and response bias between MCI and AD subjects, indicating there could be diagnostic specificity if using different test portions.…”