Complexity analysis of heartbeat-related signals in Brain MRI time series as a potential biomarker for ageing and cognitive performance

Abstract There are multiple magnet resonance imaging (MRI) based approaches to studying the ageing brain. Getting older affects both the structure of the brain and our cognitive capabilities, but there is still no solid evidence on how ageing influences the mechanisms underlying the MRI signal. Here, we apply a zero-spin echoes (ZSEs) weighted MRI sequence which recently was found to be sensitive to wakefulness. We investigated the complexity of the signal time series of this sequence in two age groups; young (18-29 years) and old (over 65 years). While comparing young and old participants, we found qualitative and quantitative evidence that the dynamics of ZSE fluctuations undergo strong changes with age. Finally, we study how differences in complexity of the ZSE signal relate with measures from different cognitive batteries, suggesting that ZSE may reveal cognitive functioning in a new. fashion. The profound sensitivity for dynamic changes shows the potential of ZSE and its underlying physiological mechanism with clinical relevance for all neurovascular diseases.