Electrical vestibular stimulation after vestibular deafferentation and in vestibular schwannoma.
BACKGROUND: Vestibular reflexes, evoked by human electrical (galvanic) vestibular stimulation (EVS), are utilized to assess vestibular function and investigate its pathways. Our study aimed to investigate the electrically-evoked vestibulo-ocular reflex (eVOR) output after bilateral and unilateral ve...
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doaj-bb0a0f3a792e40ee8ef49b968a7651822020-11-24T21:16:20ZengPublic Library of Science (PLoS)PLoS ONE1932-62032013-01-01812e8207810.1371/journal.pone.0082078Electrical vestibular stimulation after vestibular deafferentation and in vestibular schwannoma.Swee Tin AwMichael John ToddNadine LehnenGrace Elizabeth AwKonrad Peter WeberThomas EggertGabor Michael HalmagyiBACKGROUND: Vestibular reflexes, evoked by human electrical (galvanic) vestibular stimulation (EVS), are utilized to assess vestibular function and investigate its pathways. Our study aimed to investigate the electrically-evoked vestibulo-ocular reflex (eVOR) output after bilateral and unilateral vestibular deafferentations to determine the characteristics for interpreting unilateral lesions such as vestibular schwannomas. METHODS: EVOR was recorded with dual-search coils as binocular three-dimensional eye movements evoked by bipolar 100 ms-step at EVS intensities of [0.9, 2.5, 5.0, 7.5, 10.0] mA and unipolar 100 ms-step at 5 mA EVS intensity. Five bilateral vestibular deafferented (BVD), 12 unilateral vestibular deafferented (UVD), four unilateral vestibular schwannoma (UVS) patients and 17 healthy subjects were tested with bipolar EVS, and five UVDs with unipolar EVS. RESULTS: After BVD, bipolar EVS elicited no eVOR. After UVD, bipolar EVS of one functioning ear elicited bidirectional, excitatory eVOR to cathodal EVS with 9 ms latency and inhibitory eVOR to anodal EVS, opposite in direction, at half the amplitude with 12 ms latency, exhibiting an excitatory-inhibitory asymmetry. The eVOR patterns from UVS were consistent with responses from UVD confirming the vestibular loss on the lesion side. Unexpectedly, unipolar EVS of the UVD ear, instead of absent response, evoked one-third the bipolar eVOR while unipolar EVS of the functioning ear evoked half the bipolar response. CONCLUSIONS: The bidirectional eVOR evoked by bipolar EVS from UVD with an excitatory-inhibitory asymmetry and the 3 ms latency difference between normal and lesion side may be useful for detecting vestibular lesions such as UVS. We suggest that current spread could account for the small eVOR to 5 mA unipolar EVS of the UVD ear.http://europepmc.org/articles/PMC3861342?pdf=render |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Swee Tin Aw Michael John Todd Nadine Lehnen Grace Elizabeth Aw Konrad Peter Weber Thomas Eggert Gabor Michael Halmagyi |
spellingShingle |
Swee Tin Aw Michael John Todd Nadine Lehnen Grace Elizabeth Aw Konrad Peter Weber Thomas Eggert Gabor Michael Halmagyi Electrical vestibular stimulation after vestibular deafferentation and in vestibular schwannoma. PLoS ONE |
author_facet |
Swee Tin Aw Michael John Todd Nadine Lehnen Grace Elizabeth Aw Konrad Peter Weber Thomas Eggert Gabor Michael Halmagyi |
author_sort |
Swee Tin Aw |
title |
Electrical vestibular stimulation after vestibular deafferentation and in vestibular schwannoma. |
title_short |
Electrical vestibular stimulation after vestibular deafferentation and in vestibular schwannoma. |
title_full |
Electrical vestibular stimulation after vestibular deafferentation and in vestibular schwannoma. |
title_fullStr |
Electrical vestibular stimulation after vestibular deafferentation and in vestibular schwannoma. |
title_full_unstemmed |
Electrical vestibular stimulation after vestibular deafferentation and in vestibular schwannoma. |
title_sort |
electrical vestibular stimulation after vestibular deafferentation and in vestibular schwannoma. |
publisher |
Public Library of Science (PLoS) |
series |
PLoS ONE |
issn |
1932-6203 |
publishDate |
2013-01-01 |
description |
BACKGROUND: Vestibular reflexes, evoked by human electrical (galvanic) vestibular stimulation (EVS), are utilized to assess vestibular function and investigate its pathways. Our study aimed to investigate the electrically-evoked vestibulo-ocular reflex (eVOR) output after bilateral and unilateral vestibular deafferentations to determine the characteristics for interpreting unilateral lesions such as vestibular schwannomas. METHODS: EVOR was recorded with dual-search coils as binocular three-dimensional eye movements evoked by bipolar 100 ms-step at EVS intensities of [0.9, 2.5, 5.0, 7.5, 10.0] mA and unipolar 100 ms-step at 5 mA EVS intensity. Five bilateral vestibular deafferented (BVD), 12 unilateral vestibular deafferented (UVD), four unilateral vestibular schwannoma (UVS) patients and 17 healthy subjects were tested with bipolar EVS, and five UVDs with unipolar EVS. RESULTS: After BVD, bipolar EVS elicited no eVOR. After UVD, bipolar EVS of one functioning ear elicited bidirectional, excitatory eVOR to cathodal EVS with 9 ms latency and inhibitory eVOR to anodal EVS, opposite in direction, at half the amplitude with 12 ms latency, exhibiting an excitatory-inhibitory asymmetry. The eVOR patterns from UVS were consistent with responses from UVD confirming the vestibular loss on the lesion side. Unexpectedly, unipolar EVS of the UVD ear, instead of absent response, evoked one-third the bipolar eVOR while unipolar EVS of the functioning ear evoked half the bipolar response. CONCLUSIONS: The bidirectional eVOR evoked by bipolar EVS from UVD with an excitatory-inhibitory asymmetry and the 3 ms latency difference between normal and lesion side may be useful for detecting vestibular lesions such as UVS. We suggest that current spread could account for the small eVOR to 5 mA unipolar EVS of the UVD ear. |
url |
http://europepmc.org/articles/PMC3861342?pdf=render |
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