Microcirculatory Dysfunction and Oxidative Stress in Sudden Sensorineural Hearing Loss: Insights From a Case-Control and Experimental Study

BACKGROUND Sudden sensorineural hearing loss (SSNHL) is an otological emergency with incompletely understood pathophysiology. Evidence suggests microcirculatory dysfunction and oxidative stress contribute to cochlear injury; however, their interrelationship remains insufficiently characterized. MATERIAL AND METHODS This prospective case-control study enrolled 100 patients with SSNHL and 100 age- and sex-matched healthy controls. Perfusion-related surrogate parameters, including cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT), were assessed using dynamic contrast-enhanced magnetic resonance perfusion imaging. Peripheral microcirculation was evaluated by laser Doppler flowmetry. Systemic oxidative stress markers malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) were quantified in serum. Experimental validation was performed using a rat ischemia-reperfusion model to assess cochlear oxidative stress, apoptosis, and auditory brainstem response thresholds. RESULTS Compared with controls, SSNHL patients exhibited reduced CBF and CBV, prolonged MTT, and lower peripheral microcirculatory perfusion (all P