Unmasking preclinical Alzheimer's pathology: auditory distraction cost and occupational reserve jointly discriminate amyloid positivity in subjective cognitive decline.

INTRODUCTION

Conventional cognitive instruments exhibit limited efficacy in detecting insidious cognitive decline in subjective cognitive decline (SCD) due to neural compensation. We hypothesized that auditory distraction during a visual memory task would unmask preclinical amyloid beta (Aβ) vulnerability.

METHODS

We evaluated 112 participants (SCD and mild cognitive impairment [MCI]) using the MemTrax test under quiet and noisy conditions to quantify distraction costs (d-MTxc). Aβ status and cognitive reserve were assessed via positron emission tomography and the Cognitive Reserve Index questionnaire (CRIq).

RESULTS

Aβ-positive SCD individuals performed normally in quiet but showed higher d-MTxc than Aβ-negative peers (11.17 ± 5.762 vs 6.67 ± 5.096). Higher CRIq-WorkingActivity (CRIW) scores identified Aβ positivity and moderated performance. The combination of d-MTxc and CRIW accurately classified Aβ positivity (AUC = 0.836), whereas MCI individuals exhibited metabolic network fragmentation.

DISCUSSION: Auditory distraction taxes cognitive capacity to expose compensatory failures coupled with Aβ burden. This paradigm, interacting with occupational reserve, offers a promising digital biomarker framework for preclinical Alzheimer's screening.