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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...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2012
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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 |
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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 |
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