Is Ocular Counter-Roll Otolith-Ocular Reflex?

  • Hiroaki Ichijo Ichijo Ear, Nose and Throat Clinic, 3-2-1, Ekimae, Hirosaki, Japan
  • Hisako Ichijo Ichijo Ear, Nose and Throat Clinic, 3-2-1, Ekimae, Hirosaki, Japan
Keywords: vestibulo-ocular reflex, inertial force, healthy human, angular acceleration, semicircular canal, otolith organ

Abstract

Purpose

Ocular counter-roll has been thought to be an otolith-ocular reflex. However, there is a hypothesis that it is a semicircular canal (SCC) ocular reflex. This study aimed to validate whether ocular counter-roll can be explained by the SCC theory.

Methods

Experiment 1: Two springs with plastic balls (different turning radius) were fixed to a swivel chair and were rotated suddenly. Experiment 2: Subject was seated and the entire upper body was bent forward 60 degrees with the neck fixed. Experiment 3: Subject was seated, the head was twisted 45 degrees to the right and the entire upper body was bent forward 60 degrees with the neck fixed. Experiment 4 (roll rotation): Subject was asked to tilt his upper body 60 degrees to the left. Eye movements in the dark were observed and recorded using an infrared camera. In Experiments 2, 3 and 4, subjects were four healthy humans.

Results

Experiment 1: Immediately after the movement, the two balls moved tangentially. The ball on the outside spring moved more compared to the ball attached to the inside spring. Experiment 2: In all subjects, nystagmus was vertical. The direction was downward. Experiment 3: In all subjects, nystagmus was vertical/torsional. The direction was downward (torsional component was leftward). Experiment 4: In all subjects, nystagmus was torsional, and the direction was leftward.

Conclusion

Since the role of SCCs is to sense angular acceleration in all directions of 360 degrees in a coordinated manner, bilateral vertical SCCs are stimulated in roll rotation. Therefore, SCC theory can explain the generation of ocular counter-roll. We proposed the “difference of inertial forces” theory to explain the mechanism of vestibulo-ocular reflex.

References

[1] Macdougall, H. G., McGarvie, L. A., Halmagyi, G. M., Curthoys, I. S., & Weber, K. P. (2013). The video head impulse test (vHIT) detects vertical semicircular canal dysfunction. PLoS ONE, 8(4), e61488. https://doi.org/10.1371/journal.pone.0061488
[2] Fetter, M., & Sievering, F. (1995). Three-dimensional eye movement analysis in benign paroxysmal positioning vertigo and nystagmus. Acta Oto-Laryngologica, 115(3), 353-357. https://doi.org/10.3109/00016489509139328
[3] Ichijo, H. (2013). Asymmetry of positioning nystagmus in posterior canalolithiasis. Acta Oto-Laryngologica, 133(2), 159-164. https://doi.org/10.3109/00016489.2012.728293
[4] Suzuki, J.-I., Cohen, B., & Bender, M. B. (1964). Compensatory eye movements induced by vertical semicircular canal stimulation. Experimental Neurology, 9(2), 137-160. https://doi.org/10.1016/0014-4886(64)90013-5
[5] Sadeghpour, S., Fornasari, F., Otero-Millan, J., Carey, J. P., Zee, D. S., & Kheradmand, A. (2021). Evaluation of the video ocular counter-roll (vOCR) as a new clinical test of otolith function in peripheral vestibulopathy. JAMA Otolaryngology–Head & Neck Surgery, 147(6), 518-525. https://doi.org/10.1001/jamaoto.2021.0176
[6] Ichijo, H., & Teramoto, H. (2023). Eye movements induced by stimulation to the otolith organs. International Journal of Otolaryngology and Head & Neck Surgery, 12(3), 173-179. https://doi.org/10.4236/ijohns.2023.123018
[7] Ichijo, H. (2023). Affected-ear-up 90° maneuver proves that nystagmus does not occur by the stimulation to the macula of the utricle. Journal of Biosciences and Medicines, 11(5), 144-150. https://doi.org/10.4236/jbm.2023.115009
[8] Ichijo, H., & Ichijo, H. (2025). Reevaluating the role of otolith organs in nystagmus generation: An experimental approach. Modern Health Science, 8(1), 44. https://doi.org/10.30560/mhs.v8n1p44
[9] YouTube. Ocular Counter-Roll Experiments. Accessed on March 9, 2025. Retrieved from https://www.youtube.com/watch?v=8CqMB4Wdpfg
The direction of the forces experienced by the endolymph in the upper pole of SCCs during roll rotation to the left in Experiment 4. The squares represent the direction of theoretical nystagmus.
Published
2025-03-12
Section
Articles