Assessment of the otolith-autonomic response using spectral analysis of the R-R interval and blood pressure

Abstract

The effects of otolith stimulation on systolic blood pressure (SBP) and R-R interval fluctuations were investigated in 12 healthy subjects and 5 patients with loss of labyrinthine function. The vestibular otolith organs were stimulated by centrifugal forces, the constant rotation of a chair fixed outside of the rotation axis on the horizontal plane. The chair was fixed along the direction of centrifugal force (eccentric rotation [ECR]) or along the tangent line (eccentric lateral rotation [ECLR]). The ECR stimulates both the utricular and saccular maculae, whereas the ECLR stimulates only the utricular maculae. Spectral analysis showed that in the healthy subjects, low-frequency SBP increased significantly during ECR but not during ECLR. There was no significant increase in low-frequency SBP in patients with labyrinthine loss. In the R-R interval analysis, however, the low- and high-frequency components did not change significantly in the healthy subjects during ECR. Our findings indicate that stimulation of the otolith maculae, especially the saccular organs, predominantly produces augmentation of the α-sympathetic activities rather than cardiac sympathovagal outflow to the heart. (Otolaryngol Head Neck Surg 2000;123:582-6.)