Subjective cognitive decline (SCD), or self-perceived worsening of cognitive function in the absence of objective cognitive deficits, has attracted significant scientific attention, because it might reflect the earliest signs of an emerging neurodegenerative disease. Recently, investigators have struggled to standardize the measurement and definition of SCD, a complex problem because of its inherently subjective nature. Although these attempts have not resulted in consistent results, the presence of subjective cognitive decline is often associated with future objective cognitive decline and with conversion from normal cognition to mild cognitive impairment or even dementia. In this study, Buckley and colleagues investigated the independent and interactive effects of Aβ and tau aggregates, on subjective cognitive decline. They found that subjective cognitive decline was associated with accumulation of early tauopathy in the medial temporal lobe, specifically in the entorhinal cortex, and to a lesser extent, elevated global levels of Aβ. However, they cautioned that multiple biological factors must be considered when assessing subjective cognitive decline in clinically healthy older adults.
Buckley RF, Hanseeuw B, Schultz AP, Vannini P, Aghjayan SL, Properzi MJ, Jackson JD, Mormino EC, Rentz DM, Sperling RA, Johnson KA, Amariglio RE: Region-Specific Association of Subjective Cognitive Decline With Tauopathy Independent of Global β-Amyloid Burden. JAMA Neurol. [Epub ahead of print, Oct.2, 2017]; doi: 10.1001/jamaneurol.2017.2216.