Learning Strategies and Verbal Memory Deficits on the Shiraz Verbal Learning Test in Patients with Alzheimer’s Disease and Amnestic Mild Cognitive Impairment

Abstract

Background: Much remains unknown regarding the nature of the memory profile of individuals with amnestic mild cognitive impairment (aMCI). One of the questions is whether they first encounter an encoding/storage defect or retrieval memory profile difficulties. Objectives: The present study aimed to shed light on this by evaluating learning strategies and memory process deficits in individuals with aMCI and Alzheimer’s disease (AD). Methods: The Shiraz Verbal Learning Test (SVLT) was used to assess and compare verbal memory performance and learning strategies among three groups of individuals, including patients with aMCI, AD cases, and healthy individuals. The study groups were compared using most indices of the SVLT. Results: A pattern of memory impairment was found in the aMCI group, and the indicators included defects in immediate learning, a poor learning slope, rapid forgetting, and a poor function in delayed recall. This was similar to the representations of the individuals with AD. However, the aMCI group acted differently from the AD and healthy groups when it came to learning strategies. Specifically, they mostly used serial clustering. Furthermore, the results of serial position effects showed no significant difference between the three groups in terms of primary/recency effects. Conclusions: The findings of the present research suggested that individuals with aMCI, similar to patients with AD, initially develop defects in encoding and storage (to a lesser degree), followed by retrieval memory problems. Our results also supported that SVLT can be a reliable diagnostic tool to estimate aMCI progression or the prodromal stage of AD type dementia.