Prediction of amyloid-β pathology in amnestic mild cognitive impairment with neuropsychological tests.

Abstract

Assessment of disease biomarkers, particularly the in vivo assessment of amyloid-β (Aβ) burden with positron emission tomography (PET), is gradually becoming central to the diagnosis of mild cognitive impairment (MCI) due to Alzheimer's disease (AD). However, the incorporation of biomarker evidence to the diagnostic process is currently restricted mainly to research settings. The identification of memory measures that are associated with Aβ is of clinical relevance as this may enhance the confidence in making a diagnosis of MCI due to AD in clinical settings. Forty one persons with amnestic MCI underwent Aβ imaging with (18)F-Florbetaben PET, magnetic resonance imaging, and a comprehensive neuropsychological assessment. All measures of episodic memory were significantly correlated with Aβ burden, but regression analyses revealed a strong and selective association between story recall and Aβ over and beyond the effects of age, education, global cognition, hippocampal volume, or other memory tests. Analyses of sensitivity and specificity of memory measures to detect high versus low Aβ scans suggested that word-list recall performed better when high sensitivity was preferred, whereas story recall performed better when high specificity was preferred. In conclusion, a measure of story recall may increase the confidence in making a diagnosis of MCI due to AD in clinical settings.