title: Quantifying motor recovery after stroke using independent vector analysis and graph-theoretical analysis.
abstract: The assessment of neuroplasticity after stroke through functional magnetic resonance imaging (fMRI) analysis is a developing field where the objective is to better understand the neural process of recovery and to better target rehabilitation interventions. The challenge in this population stems from the large amount of individual spatial variability and the need to summarize entire brain maps by generating simple, yet discriminating features to highlight differences in functional connectivity. Independent vector analysis (IVA) has been shown to provide superior performance in preserving subject variability when compared with widely used methods such as group independent component analysis. Hence, in this paper, graph-theoretical (GT) analysis is applied to IVA-generated components to effectively exploit the individual subjects' connectivity to produce discriminative features. The analysis is performed on fMRI data collected from individuals with chronic stroke both before and after a 6-week arm and hand rehabilitation intervention. Resulting GT features are shown to capture connectivity changes that are not evident through direct comparison of the group t-maps. The GT features revealed increased small worldness across components and greater centrality in key motor networks as a result of the intervention, suggesting improved efficiency in neural communication. Clinically, these results bring forth new possibilities as a means to observe the neural processes underlying improvements in motor function.
authors.affiliation: University of Maryland, Baltimore County, Baltimore, MD 21250, United States.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Laney
authors.affiliation: University of Maryland, Baltimore County, Baltimore, MD 21250, United States.
authors.forename: Tülay
authors.initials: T
authors.lastname: Adalı
authors.affiliation: University of Maryland School of Medicine, Baltimore, MD 21201, United States.
authors.forename: Sandy
authors.initials: S
authors.lastname: McCombe Waller
authors.affiliation: University of Maryland School of Medicine, Baltimore, MD 21201, United States.
authors.forename: Kelly P
authors.initials: KP
authors.lastname: Westlake
mesh_terms: D000368:Aged; D063132:Connectome; D003627:Data Interpretation, Statistical; D005081:Exercise Therapy / Q000379:methods*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D009415:Nerve Net / Q000503:physiopathology*; D020127:Recovery of Function / Q000502:physiology*; D000071939:Stroke Rehabilitation
keywords: Graph-theoretical analysis; IVA; Stroke; fMRI