Using the Rey Auditory Verbal Learning Test (RAVLT) to differentiate Alzheimer's dementia and behavioural variant fronto-temporal dementia

In patients with focal lesions, patterns of learning, retrieval, and recognition deficits vary according to site of damage. Because different brain regions are affected by the underlying pathology in Alzheimer's dementia (AD) and behavioral variant fronto-temporal dementia (bvFTD), one might predict that the two disorders would result in different sorts of memory deficits on the Rey Auditory Verbal Learning Test (RAVLT). The aim of this investigation was to find a way to differentiate AD, bvFTD, and normal controls (NC) reliably based on RAVLT scores from retrospective samples of 82 Italian and 43 Australian participants. Results indicated that the groups differed on measures of learning, retroactive interference, delayed recall, and delayed recognition. Although delayed recall distinguished participants in the three groups across both samples, no one set of cut-offs could be obtained with adequate sensitivity and specificity. However, when we created a combined score (the "RAVLT Memory Efficiency Index": {[(delayed recall A/15)/(RAVLT Trials 1-5/75)] + [(delayed recognition hits/15) - (false positive/total number of distractors)]}), we were able to find cut-offs that differentiated the groups with good sensitivity and specificity across variations in RAVLT methodology, participant samples, and languages. This index will increase the usefulness of the RAVLT in differential diagnoses of early dementia.