Background: Internal carotid artery stenosis (ICS) can cause cognitive impairment as well as ischemic stroke. Although carotid revascularization surgery, such as carotid endarterectomy (CEA) and carotid artery stenting (CAS), may improve cognitive function, their long-term effects remain controversial. Resting-state functional MRI (rs-fMRI) enables the detection of functional connectivity (FC) changes associated with cognitive performance. In this study, we investigated the long-term effects of revascularization surgery on cognitive function and FC in patients with ICS. Methods: We conducted a prospective study in 37 patients who were expecting revascularization surgery. Cognitive assessment, including the Mini-Mental State Examination (MMSE), the Frontal Assessment Battery (FAB), and the Japanese version of the Montreal Cognitive Assessment (MoCA), as well as rs-fMRI, were performed within 1 week before surgery, and at 1 week and 6 months after surgery. For the analysis of FC, a seed region was placed in the default mode network, which is associated with cognitive function. Results: MMSE scores showed no overall difference among the three time points (χ 2 = 2.09, p = 0.35), with mean scores of 27.0 at baseline, 27.7 at 1 week, and 27.9 at 6 months; however, a significant increase was observed from preoperative to 6 months (p = 0.046). FAB scores improved significantly at all follow-ups (χ 2 = 18.02, p < 0.001), increasing from a mean of 15.1 at baseline to 15.9 at 1 week and 16.6 at 6 months. MoCA scores also showed significant improvements across all time points (χ 2 = 38.79, p < 0.001), with mean values of 22.8 at baseline, 24.6 at 1 week, and 25.9 at 6 months. FC analysis revealed increased connectivity between the medial prefrontal cortex (MPFC) and the bilateral precentral/postcentral gyri at 6 months, whereas no such increase was observed at 1 week. Conclusion: Revascularization surgery for ICS was associated with cognitive improvement, evident from 1 week on FAB and MoCA and at 6 months on MMSE. This improvement may be supported by enhanced functional connectivity between the MPFC and the bilateral precentral and postcentral gyri, suggesting a role for sensorimotor–cognitive network reorganization in postoperative recovery.
Kohta et al. (2026) studied this question.