Utility of a Modified Penlight‐Cover Test for Neurolocalization of Lesions Based on Visual Suppression of Nystagmus in Dogs and Cats With Vestibular Disease

ABSTRACT Background Humans with peripheral vestibular disorders can suppress nystagmus through visual fixation, a capability often compromised in those with central vestibular disorders. Bedside tests that exploit this difference can aid neurolocalization in humans. These tests remain unexplored in...

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Main Authors: Alice Chan, Gemma E. Longson, Edward Ives, Claire Turner, Paul Freeman, Stacey Brady, Ana Martinez Loro, Bruno Scalia, Susana Monforte Monteiro, Sara Formoso, Sam Khan, An E. Vanhaesebrouck
Format: Article
Language:English
Published: Wiley 2025-07-01
Series:Journal of Veterinary Internal Medicine
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Online Access:https://doi.org/10.1111/jvim.70182
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author Alice Chan
Gemma E. Longson
Edward Ives
Claire Turner
Paul Freeman
Stacey Brady
Ana Martinez Loro
Bruno Scalia
Susana Monforte Monteiro
Sara Formoso
Sam Khan
An E. Vanhaesebrouck
author_facet Alice Chan
Gemma E. Longson
Edward Ives
Claire Turner
Paul Freeman
Stacey Brady
Ana Martinez Loro
Bruno Scalia
Susana Monforte Monteiro
Sara Formoso
Sam Khan
An E. Vanhaesebrouck
author_sort Alice Chan
collection DOAJ
description ABSTRACT Background Humans with peripheral vestibular disorders can suppress nystagmus through visual fixation, a capability often compromised in those with central vestibular disorders. Bedside tests that exploit this difference can aid neurolocalization in humans. These tests remain unexplored in veterinary medicine. Hypothesis Removal of visual input will reveal or enhance nystagmus in animals with peripheral vestibular disease, while animals with central vestibular disease would show little change. Animals Twenty‐one dogs and cats with peripheral vestibular lesions and 16 with central vestibular lesions. Diagnosis was confirmed by MRI. Methods A prospective study was conducted using a modified penlight‐cover test. Because animals cannot be easily instructed to fixate on a visual target, removal of visual input was used as a substitute for eliminating visual fixation, based on the assumption that visual fixation also occurs spontaneously. A 0.5‐W LED penlight was shined into one eye while covering the other to eliminate visual input. Nystagmus beat frequency (BF) and subjective evaluation of slow phase velocity (SPV) were recorded before and during penlight application. Results In animals with peripheral lesions, BF increased in 33% and SPV in 24% of cases after removal of visual input. Among those with central lesions, only one of 16 showed an increase in BF, and none exhibited an increase in SPV. Conclusions When used alongside the neurological examination, the modified penlight‐cover test, could raise suspicion of a peripheral vestibular lesion if it reveals increased BF or SPV.
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spelling doaj-art-add60bbac84d4dd580a2a5ba771fd4ba2025-08-20T02:46:07ZengWileyJournal of Veterinary Internal Medicine0891-66401939-16762025-07-01394n/an/a10.1111/jvim.70182Utility of a Modified Penlight‐Cover Test for Neurolocalization of Lesions Based on Visual Suppression of Nystagmus in Dogs and Cats With Vestibular DiseaseAlice Chan0Gemma E. Longson1Edward Ives2Claire Turner3Paul Freeman4Stacey Brady5Ana Martinez Loro6Bruno Scalia7Susana Monforte Monteiro8Sara Formoso9Sam Khan10An E. Vanhaesebrouck11Queen's Veterinary School Hospital University of Cambridge Cambridge UKQueen's Veterinary School Hospital University of Cambridge Cambridge UKQueen's Veterinary School Hospital University of Cambridge Cambridge UKQueen's Veterinary School Hospital University of Cambridge Cambridge UKQueen's Veterinary School Hospital University of Cambridge Cambridge UKQueen's Veterinary School Hospital University of Cambridge Cambridge UKQueen's Veterinary School Hospital University of Cambridge Cambridge UKQueen's Veterinary School Hospital University of Cambridge Cambridge UKQueen's Veterinary School Hospital University of Cambridge Cambridge UKQueen's Veterinary School Hospital University of Cambridge Cambridge UKQueen's Veterinary School Hospital University of Cambridge Cambridge UKQueen's Veterinary School Hospital University of Cambridge Cambridge UKABSTRACT Background Humans with peripheral vestibular disorders can suppress nystagmus through visual fixation, a capability often compromised in those with central vestibular disorders. Bedside tests that exploit this difference can aid neurolocalization in humans. These tests remain unexplored in veterinary medicine. Hypothesis Removal of visual input will reveal or enhance nystagmus in animals with peripheral vestibular disease, while animals with central vestibular disease would show little change. Animals Twenty‐one dogs and cats with peripheral vestibular lesions and 16 with central vestibular lesions. Diagnosis was confirmed by MRI. Methods A prospective study was conducted using a modified penlight‐cover test. Because animals cannot be easily instructed to fixate on a visual target, removal of visual input was used as a substitute for eliminating visual fixation, based on the assumption that visual fixation also occurs spontaneously. A 0.5‐W LED penlight was shined into one eye while covering the other to eliminate visual input. Nystagmus beat frequency (BF) and subjective evaluation of slow phase velocity (SPV) were recorded before and during penlight application. Results In animals with peripheral lesions, BF increased in 33% and SPV in 24% of cases after removal of visual input. Among those with central lesions, only one of 16 showed an increase in BF, and none exhibited an increase in SPV. Conclusions When used alongside the neurological examination, the modified penlight‐cover test, could raise suspicion of a peripheral vestibular lesion if it reveals increased BF or SPV.https://doi.org/10.1111/jvim.70182neurolocalisationnystagmusveterinary
spellingShingle Alice Chan
Gemma E. Longson
Edward Ives
Claire Turner
Paul Freeman
Stacey Brady
Ana Martinez Loro
Bruno Scalia
Susana Monforte Monteiro
Sara Formoso
Sam Khan
An E. Vanhaesebrouck
Utility of a Modified Penlight‐Cover Test for Neurolocalization of Lesions Based on Visual Suppression of Nystagmus in Dogs and Cats With Vestibular Disease
Journal of Veterinary Internal Medicine
neurolocalisation
nystagmus
veterinary
title Utility of a Modified Penlight‐Cover Test for Neurolocalization of Lesions Based on Visual Suppression of Nystagmus in Dogs and Cats With Vestibular Disease
title_full Utility of a Modified Penlight‐Cover Test for Neurolocalization of Lesions Based on Visual Suppression of Nystagmus in Dogs and Cats With Vestibular Disease
title_fullStr Utility of a Modified Penlight‐Cover Test for Neurolocalization of Lesions Based on Visual Suppression of Nystagmus in Dogs and Cats With Vestibular Disease
title_full_unstemmed Utility of a Modified Penlight‐Cover Test for Neurolocalization of Lesions Based on Visual Suppression of Nystagmus in Dogs and Cats With Vestibular Disease
title_short Utility of a Modified Penlight‐Cover Test for Neurolocalization of Lesions Based on Visual Suppression of Nystagmus in Dogs and Cats With Vestibular Disease
title_sort utility of a modified penlight cover test for neurolocalization of lesions based on visual suppression of nystagmus in dogs and cats with vestibular disease
topic neurolocalisation
nystagmus
veterinary
url https://doi.org/10.1111/jvim.70182
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