Insights Into Responses to Caloric and Head Impulse Stimulation in Lateral Semicircular Canal Benign Paroxysmal Positional Vertigo

Abstract

Clinical and Experimental Otorhinolaryngology > Volume 18(4); 2025 > Article

Original Article Clinical and Experimental Otorhinolaryngology 2025; 18(4): 318-325.

Published online: April 14, 2025

DOI: https://doi.org/10.21053/ceo.2024-00365

Insights Into Responses to Caloric and Head Impulse Stimulation in Lateral Semicircular Canal Benign Paroxysmal Positional Vertigo Seong Hoon Bae1,*, Sang Hyun Kwak2,*, Jeon Mi Lee3, Ji Hyuk Han4, Dae Bo Shim5,6, Sung Huhn Kim4 1Department of Otorhinolaryngology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea

2Department of Otorhinolaryngology, St. Vincent’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea

3Department of Otorhinolaryngology-Head and Neck Surgery, Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea

4Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea

5Department of Otorhinolaryngology, Myongji Hospital, Hanyang University College of Medicine, Goyang, Korea

6The Best Care ENT Clinic, Seoul, Korea

Corresponding author: Sung Huhn Kim Department of Otorhinolaryngology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea Tel: +82-2-2228-3604, Fax: +82-2-393-0580, Email: fledermaus@yuhs.ac Co-Corresponding author: Dae Bo Shim The Best Care ENT Clinic, 6 Wangsan-ro 36-gil, Dongdaemun-gu, Seoul 02559, Korea Tel: +82-2-6235-1234, Fax: +82-2-6235-1235, Email: lovend77@gmail.com

* These authors contributed equally to this work.

Received December 19, 2024 Revised March 28, 2025 Accepted April 12, 2025 © 2025 by Korean Society of Otorhinolaryngology-Head and Neck Surgery

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Objectives. The aim of this study was to investigate the pathophysiology of persistent geotropic direction-changing positional nystagmus (pGeo DCPN) by analyzing caloric responses and the clinical course in patients with pGeo DCPN and other variants of lateral semicircular canal benign paroxysmal positional vertigo (LSCC BPPV). Methods. In this prospective case-control study, 101 patients diagnosed with pGeo DCPN (pGeo group, n=34), persistent apogeotropic (pApo) DCPN (pApo group, n=40), or transient geotropic (tGeo) DCPN (tGeo group, n=27) involving the LSCC were enrolled. The video head impulse test (vHIT) and caloric test were performed at diagnosis. If one or both tests were abnormal, follow-up testing was conducted after nystagmus resolution. Differences in test results and clinical courses among the LSCC BPPV types were analyzed and compared. Results. The mean disease duration was significantly longer in patients with pGeo (23.0 days) than those with pApo (8.0 days) and tGeo (9.0 days) (P<0.005). All patients demonstrated normal vHIT gain. The pGeo group showed the highest canal paresis (CP) value (vs. pApo: P=0.002; vs. tGeo: P<0.001) and a higher frequency of abnormal CP (61.8%) than the pApo (22.5%) and tGeo (11.1%) groups. CP was predominantly ipsilesional (85.7%) in the pGeo group. Follow-up caloric tests indicated decreased CP in 72.7% of pGeo patients, with normalization in 36.4% following the disappearance of nystagmus. Conclusion. The clinical course, caloric tests, and vHIT results indicate distinct pathophysiological mechanisms for different LSCC BPPV types. Cupular deflection due to buoyancy in pGeo DCPN plausibly leads to CP while preserving vHIT integrity.