Introduction: Intracerebral hemorrhage (ICH) has the highest mortality of all stroke subtypes. Motor deficits are a major cause of ongoing disability after ICH. However, the underlying pathophysiology of motor deficits after ICH is not clear. We hypothesized that deficits in both intrahemispheric and interhemispheric connectivity within motor networks correlate immediate hemiplegia after intracerebral hemorrhage.
Methods: We enrolled six left-sided ICH patients with hemorrhages within the basal ganglia and/or thalamus, and we performed both structural and resting-state functional MRI. Patients were divided into a hemiplegic group and a non-hemiplegic group. Seed-based were performed to evaluate motor networks. Graphs were constructed between key nodes in the motor network. Mean edge weights, as well as directional connectivity using Granger causality were derived.
Results: The motor network was significantly less connected in patients who were hemiplegic. Group analysis revealed that contralateral connectivity was preserved in non-hemiplegic patients when the map was derived from a right PMC seed, as well as in hemiplegic patients when the network was derived from a left PMC seed. Granger causality revealed that the mean flow of information was from left to right in non-hemiplegic subjects, whereas hemiplegic subjects experienced an information flow from right to left.
Conclusions: Resting fMRI differentiates hemiplegic and non-hemiplegic patients after subcortical stroke. These data, while preliminary, support a role for interhemispheric connectivity in recovery from stroke. Specifically, information flow from left to right is associated with maintenance of strength after hemorrhage and flow right to left is associated with potentially an inhibitory influence.
Patient Care: This provides the groundwork for an improved ability to prognosticate and advances our understanding of the factors which contribute to neurological deficits and recovery.
Learning Objectives: 1)Understand the relationship between motor deficits and connectivity
2)Elucidate the role of the contralesional hemisphere in the mediation of motor deficits and recovery
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