The neurovascular coupling basis of cognitive impairment in patients with H-type hypertension: a cross-modal study using resting-state fMRI and arterial spin labeling.

Objectives: To investigate local and global neurovascular coupling (NVC) alterations in H-type hypertension (HHT) and their relationships with homocysteine (Hcy) levels and cognitive deficits and whether they reflect cognitive and disease severity. Methods: Fifty-eight HHT patients and fifty normotensive healthy controls, matched for demographics and comorbidities and meeting MRI quality control standards, were included. Data collected included demographic, clinical, biochemical, cognitive, and multimodal MRI measures. NVC analysis: After preprocessing and spatial normalization to MNI space, rs-fMRI and ASL data were used to calculate indices of neural activity-ALFF, fALFF, ReHo, FCD-and cerebral blood flow (CBF). Using the AAL atlas and partial correlation, global and regional NVC values were calculated. Results: HHT patients exhibited elevated Hcy and cognitive impairment (lower MoCA/MMSE). Imaging revealed DMN alterations, increased basal ganglia ALFF, and hypertension-related CBF redistribution (decreased parietal/posterior flow; increased frontal/hippocampal flow). Global and local NVC were generally reduced, particularly in occipital and temporal regions. Crucially, global NVC correlated negatively with systolic BP and Hcy, and positively with cognitive scores. Conclusions: HHT patients exhibit reduced global and altered regional NVC-especially in somatosensory and default mode networks. Because the design is cross-sectional, these findings provide multimodal MRI evidence of how altered neurovascular coupling is associated with HHT-highlighting the neural mechanisms underlying cognitive impairment in HHT.