Abstract
Background: Post-stroke aphasia (PSA) results from brain network disorders caused by focal stroke lesions. However, it still remains largely unclear whether the impairment is present in intra- and internetwork functional connectivity (FC) within each resting-state network (RSN) and between RSNs in the subacute stage of PSA.Objectives: This study aimed to investigate the resting-state FC within and between RSNs in patients with PSA and observe the relationships between FC alterations and Western Aphasia Battery (WAB) measures.Methods: A total of 20 individuals with subacute PSA and 20 healthy controls (HCs) were recruited for functional MRI (fMRI) scanning, and only patients with PSA underwent WAB assessment. Independent component analysis was carried out to identify RSNs. Two-sample t-tests were used to calculate intra- and internetwork FC differences between patients with PSA and HCs. The results were corrected for multiple comparisons using the false discovery rate (FDR correction, p < 0.05). Partial correlation analysis was performed to observe the relationship between FC and WAB scores with age, gender, mean framewise displacement, and lesion volume as covariates (p < 0.05).Results: Compared to HCs, patients with PSA showed a significant increase in intranetwork FC in the salience network (SN). For internetwork FC analysis, patients showed a significantly increased coupling between left frontoparietal network (lFPN) and SN and decreased coupling between lFPN and right frontoparietal network (rFPN) as well as between lFPN and posterior default mode network (pDMN) (FDR correction, p < 0.05). Finally, a significant positive correlation was found between the intergroup difference of FC (lFPN-rFPN) and auditory-verbal comprehension (p < 0.05).Conclusion: Altered FC was revealed within and between multiple RSNs in patients with PSA at the subacute stage. Reduced FC between lFPN and rFPN was the key element participating in language destruction. These findings proved that PSA is a brain network disorder caused by focal lesions; besides, it may improve our understanding of the pathophysiological mechanisms of patients with PSA at the subacute stage.
Highlights
Post-stroke aphasia (PSA) is a clinical syndrome originating from the damage of language ability and comprehension due to localized stroke lesions (Thiel and Zumbansen, 2016)
We found the following results: (i) significant differences in intraand internetwork Functional connectivity (FC) between patients with PSA and healthy controls (HCs); (ii) decreased coupling between left frontoparietal network (lFPN) and right frontoparietal network (rFPN) was significantly correlated with auditory-verbal comprehension of Western Aphasia Battery (WAB); and (iii) no significant relationship was noted between intranetwork FC and WAB assessment
We found patients with PSA showing a significant decrease in FC between lFPN and rFPN
Summary
Post-stroke aphasia (PSA) is a clinical syndrome originating from the damage of language ability and comprehension due to localized stroke lesions (Thiel and Zumbansen, 2016). Regional brain activity-based rs-fMRI analysis of patients with PSA (i.e., stroke occurred in the left hemisphere) showed decreased local synchronization in multiple brain areas of the left hemisphere (Yang et al, 2016). Functional connectivity (FC)-based rs-fMRI analysis has been used to evaluate the interaction between language network and the whole brain in patients with PSA, with impressive findings (Zhu et al, 2014). Post-stroke aphasia (PSA) results from brain network disorders caused by focal stroke lesions. It still remains largely unclear whether the impairment is present in intra- and internetwork functional connectivity (FC) within each resting-state network (RSN) and between RSNs in the subacute stage of PSA
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