Cargando…

Development of Eye Position Dependency of Slow Phase Velocity during Caloric Stimulation

The nystagmus in patients with vestibular disorders often has an eye position dependency, called Alexander’s law, where the slow phase velocity is higher with gaze in the fast phase direction compared with gaze in the slow phase direction. Alexander’s law has been hypothesized to arise either due to...

Descripción completa

Detalles Bibliográficos
Autores principales: Bockisch, Christopher J., Khojasteh, Elham, Straumann, Dominik, Hegemann, Stefan C. A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3520909/
https://www.ncbi.nlm.nih.gov/pubmed/23251522
http://dx.doi.org/10.1371/journal.pone.0051409
_version_ 1782252858947665920
author Bockisch, Christopher J.
Khojasteh, Elham
Straumann, Dominik
Hegemann, Stefan C. A.
author_facet Bockisch, Christopher J.
Khojasteh, Elham
Straumann, Dominik
Hegemann, Stefan C. A.
author_sort Bockisch, Christopher J.
collection PubMed
description The nystagmus in patients with vestibular disorders often has an eye position dependency, called Alexander’s law, where the slow phase velocity is higher with gaze in the fast phase direction compared with gaze in the slow phase direction. Alexander’s law has been hypothesized to arise either due to adaptive changes in the velocity-to-position neural integrator, or as a consequence of processing of the vestibular-ocular reflex. We tested whether Alexander’s law arises only as a consequence of non-physiologic vestibular stimulation. We measured the time course of the development of Alexander’s law in healthy humans with nystagmus caused by three types of caloric vestibular stimulation: cold (unilateral inhibition), warm (unilateral excitation), and simultaneous bilateral bithermal (one side cold, the other warm) stimulation, mimicking the normal push-pull pattern of vestibular stimulation. Alexander’s law, measured as a negative slope of the velocity versus position curve, was observed in all conditions. A reversed pattern of eye position dependency (positive slope) was found <10% of the time. The slope often changed with nystagmus velocity (cross-correlation of nystagmus speed and slope was significant in 50% of cases), and the average lag of the slope with the speed was not significantly different from zero. Our results do not support the hypothesis that Alexander’s law can only be observed with non-physiologic vestibular stimulation. Further, the rapid development of Alexander’s law, while possible for an adaptive mechanism, is nonetheless quite fast compared to most other ocular motor adaptations. These results suggest that Alexander’s law may not be a consequence of a true adaptive mechanism.
format Online
Article
Text
id pubmed-3520909
institution National Center for Biotechnology Information
language English
publishDate 2012
publisher Public Library of Science
record_format MEDLINE/PubMed
spelling pubmed-35209092012-12-18 Development of Eye Position Dependency of Slow Phase Velocity during Caloric Stimulation Bockisch, Christopher J. Khojasteh, Elham Straumann, Dominik Hegemann, Stefan C. A. PLoS One Research Article The nystagmus in patients with vestibular disorders often has an eye position dependency, called Alexander’s law, where the slow phase velocity is higher with gaze in the fast phase direction compared with gaze in the slow phase direction. Alexander’s law has been hypothesized to arise either due to adaptive changes in the velocity-to-position neural integrator, or as a consequence of processing of the vestibular-ocular reflex. We tested whether Alexander’s law arises only as a consequence of non-physiologic vestibular stimulation. We measured the time course of the development of Alexander’s law in healthy humans with nystagmus caused by three types of caloric vestibular stimulation: cold (unilateral inhibition), warm (unilateral excitation), and simultaneous bilateral bithermal (one side cold, the other warm) stimulation, mimicking the normal push-pull pattern of vestibular stimulation. Alexander’s law, measured as a negative slope of the velocity versus position curve, was observed in all conditions. A reversed pattern of eye position dependency (positive slope) was found <10% of the time. The slope often changed with nystagmus velocity (cross-correlation of nystagmus speed and slope was significant in 50% of cases), and the average lag of the slope with the speed was not significantly different from zero. Our results do not support the hypothesis that Alexander’s law can only be observed with non-physiologic vestibular stimulation. Further, the rapid development of Alexander’s law, while possible for an adaptive mechanism, is nonetheless quite fast compared to most other ocular motor adaptations. These results suggest that Alexander’s law may not be a consequence of a true adaptive mechanism. Public Library of Science 2012-12-12 /pmc/articles/PMC3520909/ /pubmed/23251522 http://dx.doi.org/10.1371/journal.pone.0051409 Text en © 2012 Bockisch et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Bockisch, Christopher J.
Khojasteh, Elham
Straumann, Dominik
Hegemann, Stefan C. A.
Development of Eye Position Dependency of Slow Phase Velocity during Caloric Stimulation
title Development of Eye Position Dependency of Slow Phase Velocity during Caloric Stimulation
title_full Development of Eye Position Dependency of Slow Phase Velocity during Caloric Stimulation
title_fullStr Development of Eye Position Dependency of Slow Phase Velocity during Caloric Stimulation
title_full_unstemmed Development of Eye Position Dependency of Slow Phase Velocity during Caloric Stimulation
title_short Development of Eye Position Dependency of Slow Phase Velocity during Caloric Stimulation
title_sort development of eye position dependency of slow phase velocity during caloric stimulation
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3520909/
https://www.ncbi.nlm.nih.gov/pubmed/23251522
http://dx.doi.org/10.1371/journal.pone.0051409
work_keys_str_mv AT bockischchristopherj developmentofeyepositiondependencyofslowphasevelocityduringcaloricstimulation
AT khojastehelham developmentofeyepositiondependencyofslowphasevelocityduringcaloricstimulation
AT straumanndominik developmentofeyepositiondependencyofslowphasevelocityduringcaloricstimulation
AT hegemannstefanca developmentofeyepositiondependencyofslowphasevelocityduringcaloricstimulation