A longitudinal evaluation of personalized intrinsic network topography and cognitive decline in Parkinson’s disease

Abstract

AbstractResting state functional MRI (R-fMRI) offers insight into how synchrony within and between brain networks is altered in disease states. Individual and disease-related variability in intrinsic connectivity networks may influence our interpretation of R-fMRI data.MethodsWe used a personalized approach designed to account for individual variation in the spatial location of correlation maxima to evaluate R-fMRI differences between Parkinson’s disease (PD) patients who showed cognitive decline, those who remained cognitively stable, and cognitively stable controls. We compared fMRI data from these participant groups, studied at baseline and 18 months later, using both Network-based Statistics (NBS) and calculations of mean inter- and intra-network connectivity within pre-defined functional networks.ResultsThe NBS analysis showed that PD participants who remained cognitively stable showed exclusively (at baseline) or predominantly (at follow-up) increased intra-network connectivity, whereas decliners showed exclusively reduced intra-network and inter-(ventral attention and default mode) connectivity, in comparison to the control group. Evaluation of mean connectivity between all ROIs within a priori networks showed that decliners had consistently reduced inter-network connectivity for ventral attention, somatomotor, visual, and striatal networks, and reduced intra-network connectivity for ventral attention network to striatum and cerebellum.ConclusionsThese findings suggest that specific functional connectivity covariance patterns differentiate PD cognitive subtypes and may predict cognitive decline. Further, increased intra and internetwork synchrony may support cognitive function in the face of PD-related network disruptions.Key PointsResting state functional MRI (R-fMRI) can be used to probe changes in brain networks related to disease. Personalized approaches can be used to address spatial variations in R-fMRI correlation maxima influenced by individual variation or brain plasticity in response to disease.Longitudinal R-fMRI from cognitively stable Parkinson’s patients were compared with those who experienced decline as well as controls using a personalized approach.Cognitively stable patients showed increased inter and intra-network synchrony while decliners showed decreases that may have preceded cognitive decline.