The human vestibulo-ocular reflex and compensatory saccades in schwannoma patients before and after vestibular nerve section

Jacob M Pogson; Rachael L Taylor; Andrew P Bradshaw; Leigh McGarvie; Mario D'Souza; Sean Flanagan; Jonathan Kong; Nigel Biggs; Brindha Shivalingam; Simon Greenberg; Glen Croxson; G Michael Halmagyi; Miriam S Welgampola

doi:10.1016/j.clinph.2022.02.014

The human vestibulo-ocular reflex and compensatory saccades in schwannoma patients before and after vestibular nerve section

Clin Neurophysiol. 2022 Jun:138:197-213. doi: 10.1016/j.clinph.2022.02.014. Epub 2022 Mar 1.

Authors

Affiliations

¹ Sydney Medical School, The University of Sydney, Sydney, Australia; Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Sydney, Australia; Otolaryngology, Head, Neck and Skull Base Surgery Department, St Vincent's Hospital, Sydney, Australia.
² Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Sydney, Australia; Department of Physiology, University of Auckland, Auckland, New Zealand.
³ Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Sydney, Australia.
⁴ School of Psychology, The University of Sydney, Sydney, Australia; Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Sydney, Australia.
⁵ Sydney Medical School, The University of Sydney, Sydney, Australia; Clinical Research Centre, Royal Prince Alfred Hospital, Sydney, Australia.
⁶ Otolaryngology, Head, Neck and Skull Base Surgery Department, St Vincent's Hospital, Sydney, Australia; Faculty of Medicine, University of New South Wales, Sydney, Australia.
⁷ Neurosurgery Department, Royal Prince Alfred Hospital, Sydney, Australia; Otolaryngology Head and Neck Surgery Department, Royal Prince Alfred Hospital, Sydney, Australia.
⁸ Otolaryngology, Head, Neck and Skull Base Surgery Department, St Vincent's Hospital, Sydney, Australia.
⁹ Otolaryngology Head and Neck Surgery Department, Royal Prince Alfred Hospital, Sydney, Australia.
¹⁰ Ear Nose and Throat Department, St George Private Hospital, Sydney, Australia.
¹¹ Sydney Medical School, The University of Sydney, Sydney, Australia; Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Sydney, Australia.
¹² Sydney Medical School, The University of Sydney, Sydney, Australia; Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Sydney, Australia. Electronic address: miriam@icn.usyd.edu.au.

PMID: 35370080
DOI: 10.1016/j.clinph.2022.02.014

Abstract

Objective: To examine the vestibulo-ocular reflex (VOR) and compensatory-saccades before and after complete unilateral vestibular deafferentation (UVD).

Methods: Forty patients were studied before and after surgery for vestibular or facial schwannoma using the video head-impulse test (vHIT) and multivariable regression.

Results: Prior to UVD (median(IQR), 14(58.4) days), the average VOR-gain towards the lesioned-ear was lower than in normal for all semicircular canals (lateral, anterior, posterior: 0.69, 0.72, 0.49). One-week after UVD (5(3.0) days) VOR gains were further reduced (0.22, 0.37, 0.27), however, within one-year after UVD (171(125.0) days) the lesioned-ear VOR gains had slightly increased (+0.08, +0.11, +0.03), maximally for the anterior-canal. After UVD, the VOR gain asymmetry (gain towards minus away from intact-ear) was lower for the intact posterior-canal plane (0.56, 0.56, 0.22). For the lesioned canals, the frequency and amplitude of the first compensatory-saccade increased from 61-93% and 1.9-3.6° pre-surgery, to 98-99% and to 3.1-5.9° one-week post-surgery and remained unchanged over one-year; second saccade frequency and amplitude decreased over the same timespan.

Conclusions: After UVD the high-acceleration VOR for the intact posterior-canal plane is more symmetrical than the other canals. First compensatory-saccades adapt within one week and subsequently change only marginally.

Significance: Saccade compensation from surgical UVD is near complete by one-week.

Keywords: Saccades; Schwannoma; Vestibular system; Vestibulo-ocular reflex; Video head impulse test.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Head Impulse Test
Humans
Neurilemmoma*
Reflex, Vestibulo-Ocular* / physiology
Saccades
Semicircular Canals
Vestibular Nerve

Associated data

figshare/10.6084/m9.figshare.8868218