White matter hyperintensity burden does not differentiate SuperAgers from average cognitive agers

Abstract

AbstractBackgroundThe amount of white matter hyperintensity (WMH) found on T2‐weighted imaging has shown a strong relationship with age and is thought to be a marker of ischemia‐associated demyelination or secondary axonal degeneration associated with neurodegenerative disease. Previous healthy older aging studies have shown increased WMH are associated with poorer episodic memory performance and decreased volume of medial temporal lobe regions. Here, we examine if lower WMH are associated with a phenotype of successful cognitive aging, SuperAging. SuperAgers are participants over the age 80 with episodic memory at least as good as that of average middle‐aged adults.MethodWe quantified the WMH volume from T2‐FLAIR imaging with a pre‐trained Bayesian 3D U‐Net convolutional neural network in SuperAgers and cognitively healthy elderly controls (EC) of a similar age and education. All participants underwent the ADNI‐3 FLAIR on the same 3T Prisma MRI. WMH volume was square root transformed to account for the skewed distribution. A 2‐tail independent samples t‐test evaluated the difference in WMH volume between SuperAgers and EC. Additionally, we examined if there were differences within SA and EC groups by sex.Result46 SuperAgers (average age 86.3 ± 1.86; average years of education 16.9 ± 1.9) and 25 EC (average age 87.1 ± 5.17; average years of education 17.1 ± 3.1) met criteria and were included in the study. There was no significant difference in the volume of WMH between SuperAgers and ECs (t = 1.01, p = 0.32). Further, there was no significant difference in WMH by sex within the SuperAging group (t = 0.10, p = 0.92) or EC group (t = 0.82, p = 0.42).ConclusionResistance to the development of WMH, a cross‐sectional marker of cerebrovascular disease and demyelination, does not appear to be a strong discriminating factor in 80+ year‐olds with superior memory function compared to cognitively average agers. Future analyses will include longitudinal changes in WMH and examining regional WMH. Cognitive aging is associated with several underlying brain‐based etiologies, and SuperAging may be better explained by a more sophisticated multi‐modal approach.