Neurovascular coupling dysfunction associated with inflammatory factors in sudden sensorineural hearing loss.

Purpose: The neuropathologic mechanisms of sudden sensorineural hearing loss (SSNHL) are unknown. The aim of this study was to investigate the alterations of neurovascular coupling (NVC) in patients with SSNHL and its association with hematologic inflammatory factors.

Methods: The amplitude of low-frequency fluctuations (ALFF), fractional amplitude of low-frequency fluctuations (fALFF), regional homogeneity (ReHo), and degree centrality (DC) were calculated in 48 patients with SSNHL and 54 age-, gender-, and education-matched healthy control (HC), and also utilized the arterial spin labeling imaging (ASL) to calculate cerebral blood flow (CBF). Four indices of NVC (CBF-ALFF, CBF-fALFF, CBF-ReHo, and CBF-DC) in the whole brain gray matter as well as the NVC ratio were compared between two groups. In addition, correlation analyses were performed with inflammatory factors for the NVC indexes at the global level and regional level, respectively.

Results: The NVC at global level was lower in SSNHL group than in HC, except for CBF-ALFF. At the regional level, most of the brain regions with abnormal NVC in SSNHL patients involved auditory and sensorimotor language centers and limbic system compared to HC. In addition, both at the global and regional levels, NVC metrics were shown to correlate with partial inflammatory factors or hematologic parameters, including platelet-lymphocyte ratio (PLR), neutrophil-lymphocyte ratio (NLR), systemic immunoinflammatory index (SII), blood platelet count (PLT), and lymphocyte count (Lym).

Conclusion: From the view of the NVC metrics, these findings provide new perspectives on the neuropathologic mechanisms and clinical treatment of SSNHL.