Age-related differences in neural integrity are unrelated to prospective memory age effects

Prospective memory refers to memory for future intentions. In general, prospective memory appears to decline with age when tested in laboratory settings but is preserved or enhanced when tasks need to be completed in daily life. No study to date has tested whether age-related differences in specific brain structures and networks mediate prospective memory age effects in both settings. Here, measures of regional brain volume (anterior prefrontal cortex, frontoparietal networks, and temporal lobes), white matter integrity (prefrontal white matter hypointensities) and prospective memory were obtained from 41 younger and 41 older adults. The results showed that, as expected, older age was associated with smaller regional brain volumes, as well as poorer prefrontal white matter integrity. In addition, age was negatively associated with prospective memory function in the laboratory-based assessment, but positively associated with performance on the task completed in daily life. However, none of these behavioural effects were mediated by age-related differences in neural integrity. These data show that, in contrast to literature focused on neurodegenerative disease in which neural losses have been shown to be predictive of PM impairment, age-related differences in brain integrity may not be the best indicator of normal variation in prospective memory function.