Specific Neuroimaging Signatures of Superagers in an Urban Indian Ageing Cohort

Abstract Background Decline in cognitive functioning is one significant change that occurs as people age. But, certain individuals in the community have their cognitive functioning on par with people 20‐30 years younger than them. Such individuals above the age of 80 are referred to as superagers. Previous studies identified higher brain volumes in superagers compared to typical agers. The present study aims to identify superagers in an urban Indian cohort and compare their imaging parameters with those of typical agers. Method The study used baseline data from Tata Longitudinal Study of Ageing (CBR‐TLSA). The 65 octogenarians of the cohort were screened based on the Northwestern criteria for superagers. The criteria includes one memory test score being equal to or greater than the mean of 50‐65‐year‐old gender and education‐matched controls, and scores in three tests of other cognitive domains not being less than 1 standard deviation of the octogenarian group. Neuroimaging was performed for a subset of the octogenarians using a 3 Telsa MR scanner. Generalised linear models were used to identify associations of brain region volumes with cognition after adjusting for total intracranial volumes. Result A total of 14 superagers were identified in the TLSA cohort based on the criteria mentioned. Superagers were found to have significantly larger right (p = 0.01) and left hippocampus (p<0.001) owing to better memory scores in them. The total volumes of cortex (p<0.001), cerebral white matter (p = 0.02), brain stem (p = 0.037) and subcortical grey matter (p = 0.01) were greater in superagers. The right (p = 0.024) and left thalamus (p = 0.014), right cerebellum cortex (p = 0.048) and left cerebellum white matter (p = 0.025) volumes were also found to be significantly higher in superagers when compared with typical agers. Conclusion The results identified higher volumes of specific brain regions across both hemispheres among superagers as compared to typical agers. Further, studies on superaging from healthy ageing cohorts are necessary to identify factors contributing to cognitive reserve.