A Practical Screening Combination for the Discrimination of Alzheimer’s Type Memory Impairment Continuum: The 5-word Test and Magnetic Resonance Imaging-visual Rating Scale

Abstract

Introduction: Alzheimer’s disease (AD) is a continuum with four clinical stages: asymptomatic, subjective cognitive impairment (SCI), mild cognitive impairment (MCI), and AD dementia (ADD). Identification of the predementia stages had become particularly essential after the recent approval of three anti-amyloid-β monoclonal antibodies. This study aimed to evaluate their contribution to the diagnosis of AD by using two practical instruments: The 5-word test (5WT) and medial temporal atrophy (MTA) scoring together. Materials and Methods: Twenty six ADD, 29 MCI, and 25 SCI patients matched for age, sex, and education were included. The Addenbrooke’s Cognitive Examination-Revised version, which includes the Mini-Mental Status Examination, and 5WT were applied. MTA is scored on coronal T1 magnetic resonance images, between 0 and 4 (0: Severe atrophy, 4: No atrophy). A receiver operating characteristic curve analysis was performed to test the success of the MTA score, screening tests, and scores formed from various combinations of these two in classifying the groups. Results: MTA + 5WT had the highest area under curve (AUC) differentiating SCI versus MCI with a sensitivity of 0.80 and a specificity of 0.83, and differentiating SCI versus ADD with a sensitivity and specificity of 1.0. For differentiating MCI versus ADD, MTA + 5WT had a very good performance with an AUC of 0.93, a specificity of 0.96, and a moderate sensitivity of 0.76. Conclusion: Combining 5WT for memory test with MTA for atrophy rating becomes a perfect method in a clinical setting for evaluating patients with memory complaints and thus carefully selecting the candidates for advanced biological diagnosis.