Relationship between autonomic nervous system function and endolymphatic space ratio in Ménière disease

Autonomic dysfunction is associated with Ménière disease (MD) and benign paroxysmal positional vertigo (BPPV). Because the autonomic nervous system regulates blood pressure (BP) and heart rate (HR) during positional changes, these changes can be used to assess autonomic nervous system function. We aimed to evaluate the relationship between MD/BPPV and autonomic nervous system function based on BP, HR, and endolymphatic space (ELS) ratio measurements, and to examine the differences between the two diseases.

This retrospective study included 168 patients who underwent inner ear magnetic resonance imaging (MRI), Schellong test (S-test), and HR measurements and were diagnosed with MD (n = 103) or BPPV (n = 65) between August 2014 and January 2024. The ELS ratios of the entire inner ear, cochlea, vestibule, and semicircular canals were calculated using MRI. The ranges of BP and HR changes during position changes were calculated and related to each ELS ratio.

Forty (38.8 %) patients with MD had a positive S-test result, which was significantly higher than the number of patients with BPPV who had a positive S-test result (n = 15, 23.1 %) (P = 0.0427, Fisher's exact test). A trend toward a significant increase in the cochlear ELS ratio with decreasing systolic BP was observed in patients with MD with a positive S-test (Spearman's test, r=-0.346, P = 0.0287). No significant differences were observed between the other combination groups.

Autonomic nervous system function may influence the onset of MD more than BPPV, furthermore, MD patients with S-test positive, a weak correlation was observed between an increased ELS ratio in the cochlear and a decrease in systolic BP.