BBRC researchers identify cognitive and brain volumetric profile differences in individuals with subjective cognitive decline

A team led by José Luis Molinuevo, scientific director of the Alzheimer’s Prevention Program at the Barcelonaβeta Brain Research Center (BBRC), identified that some individuals who perceive subjective cognitive decline have a worse cognitive performance and lower grey matter volumes in areas which are affected by Alzheimer’s disease. The study received funding from "la Caixa" and was published in Alzheimer’s Research and Therapy. 

Subjective cognitive decline is defined as a self-experienced persistent decline in cognitive capacity in comparison with a previously normal status and not related to an acute event, and it is supposed to precede mild cognitive impairment. Despite it is normal to perceive a decline in memory and other cognitive capacities with ageing, different factors affect this subjective perception.

In 2014, Molinuevo and international colleagues described a set of seven specific features which are associated with an increased likelihood to be an expression of the preclinical stage of Alzheimer’s disease. These features are related to age (+60 years old), genetics, the onset of the decline and the confirmation of cognitive decline by an informant, among other features. 

Taking into account these features, BBRC researchers analysed the data from 2,670 research participants of the Alfa Cohort. Subjects were classified as not self-reporting cognitive decline (79%) and self-reporting cognitive decline (21%). Within the self-reporting decliners group, participants were also classified according to the number of features they met: less than 3 features (56%) and more than 3 (44%). 

Research participants underwent clinical and cognitive explorations, and some of them had Magnetic Resonance Imaging (MRI). The findings showed that individuals with more features of subjective cognitive decline had a distinct cognitive and brain volumetric profile similar to that found in Alzheimer’s disease. Specifically, they presented a lower volume in areas affected by Alzheimer’s disease such as the hippocampus, the temporal lobe, the cerebellum and the precuneus. On the other hand, researchers also identified that confirmation of the cognitive decline by an informant was the only feature that predicted lower hippocampal volume and worse cognitive performance. 

“This study may contribute to better stratify people who have an increased risk of Alzheimer’s disease and to better determine this risk. The identification of subjective cognitive decline features may also contribute to improve the selection of research participants for clinical trials and multimodal intervention studies of Alzheimer’s prevention”, says Molinuevo. 

The next step of BBRC researchers is exploring the association of these results with other biomarkers of the disease, such as the presence of amyloid plaques and Tau tangles. 

The CIBER on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN) and the CIBER on Fragility and Healthy Ageing (CIBERFES) collaborated with this research.