Resting-State Connectivity in Acute and Subacute Poststroke Aphasia: A Functional Near-Infrared Spectroscopy Pilot Study
Erin L. Meier, Lisa Bunker, Hana Kim, Argye E. Hillis
Abstract
Background: Understanding how brain function and language skills change during early (acute and subacute) stroke phases is critical for maximizing patient recovery, yet functional neuroimaging studies of early aphasia are scarce. In this pilot study, we used functional near-infrared spectroscopy (fNIRS) to investigate how resting-state functional connectivity (rs-FC) in early aphasia differs from neurologically healthy adults and is related to language deficits. Materials and Methods: Twenty individuals with aphasia (12 acute and 8 subacute phase) and 15 healthy controls underwent rs-fNIRS imaging with a 46-channel montage centered over bilateral perisylvian language areas. FC was computed using a prewhitening, autoregressive Pearson correlation routine applied to preprocessed oxyhemoglobin (HbO) data. Connections were classified as left intra-, right intra-, or interhemispheric. We then compared rs-FC between groups by connection type and examined Spearman correlations between rs-FC averages and language measures within patients. Results: Participants in the acute phase had significantly reduced global rs-FC across all HbO-based connections compared to healthy controls. No significant differences were found in rs-FC between controls and patients in the subacute phase. Controlling for days since stroke, stronger right intra- and interhemispheric rs-FC was related to milder aphasia across all patients. Exploratory correlations revealed that relationships between language measures and rs-FC differed between acute and subacute patient groups. Conclusion: This study provides preliminary evidence that fNIRS-based rs-FC measures may be a viable metric to index the early impacts of stroke in people with aphasia.