Memorability of photographs in subjective cognitive decline and mild cognitive impairment: Implications for cognitive assessment

Alzheimers Dement (Amst). 2019 Sep 5:11:610-618. doi: 10.1016/j.dadm.2019.07.005. eCollection 2019 Dec.

Abstract

Introduction: Impaired long-term memory is a defining feature of mild cognitive impairment (MCI). We tested whether this impairment is item specific, limited to some memoranda, whereas some remain consistently memorable.

Methods: We conducted item-based analyses of long-term visual recognition memory. Three hundred ninety-four participants (healthy controls, subjective cognitive decline [SCD], and MCI) in the multicentric DZNE-Longitudinal Cognitive Impairment and Dementia Study (DELCODE) were tested with images from a pool of 835 photographs.

Results: We observed consistent memorability for images in healthy controls, SCD, and MCI, predictable by a neural network trained on another healthy sample. Looking at memorability differences between groups, we identified images that could successfully categorize group membership with higher success and a substantial image reduction than the original image set.

Discussion: Individuals with SCD and MCI show consistent memorability for specific items, while other items show significant diagnosticity. Certain stimulus features could optimize diagnostic assessment, while others could support memory.

Keywords: Alzheimer's disease (AD); Diagnostic assessment; Image analysis; Memorability; Mild cognitive impairment (MCI); Subjective cognitive decline (SCD).