Higher CSF Ab38 levels protect against cognitive decline in high‐functioning individuals

The amyloid cascade hypothesis proposes that Alzheimer’s disease (AD) pathology starts with accumulation of b‐amyloid (Ab) peptides, leading to plaque deposition. In this context, the spotlight has been pointed firmly onto Ab42, but evidence suggests that shorter isoforms may also play an important role in modulating AD pathophysiology. A recent report with individuals with mild cognitive impairment or subjective cognitive decline (Cullen et al., 2021) has shown that higher cerebrospinal fluid (CSF) levels of Ab38 were associated with less decline on the mini‐mental state exam (MMSE) score and reduced risk of conversion to AD. The aim of this study was to test whether CSF Ab38 levels also predicted change in MMSE scores in cognitively intact individuals.