Is there a cognitive measure of neurodegeneration for amyloid-Aβ-ratio probable Alzheimer's disease patients?

BackgroundRecent developments in the assessment of Alzheimer's disease (AD) have centered on differential diagnostic questions. Only a few studies have aimed to identify neuropsychological measures that allow the prediction of disease progression. However, this question is central to informing patients about their diagnosis and to decisions regarding the urgency and timing of treatment escalation.ObjectiveWe analyzed which, if any, neuropsychological test results reflect the extent of neurodegenerative progression.MethodsThis retrospective analysis included 290 patients divided into an Aβ-ratio + group (n = 146; AD biomarker profile) and an Aβ-ratio- group (n = 144; non-AD biomarker profile). The Aβ-ratio + group was further divided into four t-tau quartiles. The Aβ-ratio- group was subdivided into patients with normal (n = 94) or elevated t-tau (n = 50).ResultsRegression and variance analyses demonstrated a correlation between Trail Making Test B (TMT-B) performance and t-tau levels in patients with an Aβ-ratio+, driven by differences between low and high tau values, but not in Aβ-ratio- patients. Several additional statistical control analyses endorsed this finding.ConclusionsWe conclude that, for Aβ-ratio + patients, TMT-B performance may serve as a clinically accessible indicator of tau-related disease activity and the extent of neurodegeneration and may help identify patients at risk of faster progression if replicated in longitudinal studies.