Brain age estimation by structural MRI in superagers: a BrainAGE approach in elderly people with youthful episodic memory

Background Age‐related episodic memory decline is not the only trajectory of healthy ageing. Superagers are the living proof that an 80yo can have the memory of a 50‐60yo. We aim to estimate the biological brain age of superagers using the BrainAGE approach to understand the underlying ageing process. In the context of normal ageing, resistance refers to the avoidance of ageing effects and will translate into a deceleration of the ageing process, whereas resilience is the successful coping with age‐related changes and will translate into a similar estimated brain age and chronological age. We tested these hypotheses in this study. Method A sample of 63 superagers (mean age 81.8 years ± 1.8 std, 60.3% women) and 55 age‐matched controls (mean age 82.4 years ± 1.9 std, 63.6% women) from the Vallecas Project cohort in Madrid, Spain, were selected according to their episodic memory score in the Free and Cued Selective Reminding Test. Superagers scored at or above the mean value of a 50‐56yo person, whereas controls scored within one standard deviation for their age. BrainAGE (“Brain Age Gap Estimation”) aggregates to a single value the complex multidimensional aging pattern within the whole brain by applying established kernel regression methods to anatomical brain magnetic resonance images (Franke and Gaser 2019). The BrainAGE score was calculated for both groups as the difference between chronological age and estimated brain age. Positive values indicate an acceleration of the ageing process and negative values indicate a deceleration of the ageing process. Result The BrainAGE score of superagers was ‐0.5 years, showing that their estimated brain age is lower than their chronological age whereas the estimated brain age of the control group is similar to their chronological age. The difference in BrainAGE between the superager and the control group is significant ( p = 1x10 ‐6 ). This result indicates a deceleration in the brain ageing process of superagers compared to age‐matched controls. Conclusion Superagers showed a slowing of the structural brain age‐related changes compared to the control group. These results suggest that superagers, selected for their youthful episodic memory, show whole‐brain resistance to the ageing process.