Age affects white matter microstructure and episodic memory across the older adult lifespan

Bridging Patterns of Neurocognitive Aging Across the Older Adult Lifespan

“…For example, the previously mentioned age-related increases in brain-wide WMH were observed even in older adults with superior cognition (Yang et al, 2016a), and the larger age effect on parietal than frontal WMH was independent of APOE genotype (Piguet et al, 2003). Moreover, our finding of brain-wide microstructure declines across the older adult lifespan (Merenstein et al, 2021) and within only oldest-old adults (Bennett et al, 2017) did not change after excluding oldest-old adults diagnosed with CIND. Thus, brain-wide microstructural degradation seen in advanced age cannot solely be attributed to disease-related pathology.…”

“…For example, linear age-related declines in microstructure have been reported in frontal, temporal, and parietal regions across the older adult lifespan (Lövdén et al, 2013), as well as within oldest-old adults over a two-year period (Lövdén et al, 2014). Our own work in younger-old and oldest-old adults revealed quadratic age-related declines in white matter microstructure across the brain, with the largest age effects seen for the medial temporal lobe (Merenstein et al, 2021). These findings extended earlier work in which we found the largest age effects for medial temporal (fornix) and posterior (splenium) white matter tracts within oldest-old adults (Bennett et al, 2017).…”

“…For example, within oldest-old adults, those with slower rates of memory decline also had fewer baseline WMH across the brain (Pelkmans et al, 2021). Better episodic memory performance has also been related specifically to better medial temporal white matter microstructure (65-98 years; Merenstein et al, 2021), as well as better hippocampal gray matter microstructure across the older adult (56-99 years; Reas et al, 2021) and entire (4-93 years; Langnes et al, 2020) lifespan. In two of these studies, the negative effect of age on episodic memory performance was significantly mediated by medial temporal (Merenstein et al, 2021) or hippocampal (Reas et al, 2021) microstructure.…”

“…Better episodic memory performance has also been related specifically to better medial temporal white matter microstructure (65-98 years; Merenstein et al, 2021), as well as better hippocampal gray matter microstructure across the older adult (56-99 years; Reas et al, 2021) and entire (4-93 years; Langnes et al, 2020) lifespan. In two of these studies, the negative effect of age on episodic memory performance was significantly mediated by medial temporal (Merenstein et al, 2021) or hippocampal (Reas et al, 2021) microstructure. For executive functions, older adults who accumulated fewer brain-wide WMH over time had smaller declines in performance (Carmichael et al, 2012), although the association between WMH burden and executive functions may be weaker in oldest-old adults (Legdeur et al, 2019).…”

Bridging patterns of neurocognitive aging across the older adult lifespan

“…Studies examining white matter microstructure have reported negative age effects on frontal, temporal, and parietal regions across the older adult lifespan (Lövdén et al, 2013), as well as within oldest-old adults over a two-year period (Lövdén et al, 2014). Our own work in younger-old and oldest-old adults revealed quadratic age-related differences in white matter microstructure across the brain that were more pronounced in advanced age, with the largest effects seen for the medial temporal lobe (Merenstein et al, 2021). These findings extended earlier work in which we found the largest age effects for medial temporal (fornix) and posterior (splenium) white matter tracts within oldest-old adults (Bennett et al, 2017).…”