Neurovascular Coupling Dysfunction: An Early Indicator of Brain Injury in Asymptomatic Moyamoya Disease.

INTRODUCTION

This study investigated structural and functional impairments in asymptomatic Moyamoya Disease (MMD) patients with normal signals to support early interventions. It focused on Neurovascular Coupling (NVC), cerebral perfusion, neural activity, and white matter microstructure in adults with unilateral and bilateral MMD, examining their impact on cognitive function.

METHODS

119 asymptomatic MMD adults (57 unilateral, 62 bilateral) underwent MRI assessments. Data on demographics, clinical, and neuropsychological parameters were collected. Comparative analyses of Cerebral Blood Flow (CBF), white matter diffusion, neuronal activity, and NVC were conducted, with Spearman correlation analyses assessing the link between imaging differences and cognitive function, adjusting for multiple comparisons.

RESULTS

The study identified that patients with bilateral asymptomatic MMD had lower NVC across two coupling modes (P = 0.004/0.049) and fractional anisotropy within two clusters (P = 0.028/0.039), alongside higher radial diffusivity in three clusters (P = 0.046) compared to those with unilateral involvement. While neuronal activity differed, CBF changes were not significant. NVC demonstrated a positive correlation with fractional anisotropy (P = 0.005) and was negatively related to radial diffusivity across two clusters (P = 0.025/0.018). Furthermore, both fractional anisotropy (P = 0.031) and NVC were positively associated with cognitive performance (P = 0.003).

DISCUSSION: This study shows that in asymptomatic MMD patients with normal signals, bilateral vascular involvement leads to more severe NVC impairments, despite similar CBF levels. This condition may worsen white matter damage and increase the risk of cognitive decline and adverse outcomes as the disease progresses. Early detection of NVC dysfunction could indicate a higher risk of future clinical issues and guide decisions on vascular reconstruction surgery. These findings suggest that NVC is an earlier indicator of brain dysfunction than traditional CBF measures in asymptomatic MMD patients.

CONCLUSION

Bilateral asymptomatic MMD is associated with greater NVC impairment, possibly worsening microstructural damage and cognitive decline, suggesting a basis for targeted interventions.