| The linear vestibulo-ocular reflex, locomotion and falls in neurological disorders. | |
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MedLine Citation:
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PMID: 20086286 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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PURPOSE: During locomotion, head perturbations, consisting of rotations and translations (linear movements), occur with predominant frequencies of 0.5-5.0 Hz. The vestibular reflexes act at short latency to safeguard clear vision and stable posture during locomotion. Much is known about the angular vestibulo-ocular reflex (aVOR) in response to head rotations, which depend on the semicircular canals of the vestibular labyrinth. However, the means to test reliably the linear or translational vestibulo-ocular reflex (tVOR), which depends on the otolithic organs, has only become available more recently. METHODS: We used a moving platform to translate normal human subjects vertically at frequencies similar to those occurring during locomotion, under ambient illumination. RESULTS: Our findings suggested that, whereas aVOR is concerned with stabilizing images of visual targets on the retina to optimize visual acuity, tVOR seems best suited to minimize retinal image motion between objects lying in different depth planes, in order to optimize motion parallax information. We then asked whether the tVOR functioned abnormally in patients with two neurological disorders that often cause falls: progressive supranuclear palsy (PSP) and cerebellar ataxia. We found that patients with PSP cannot adjust tVOR responses appropriately during viewing of near objects, nor converge their eyes. Vestibular-evoked myogenic potentials (VEMPs), an otolith-spinal reflex, are also impaired in PSP patients. Patients with cerebellar ataxia also lack the ability to adjust tVOR for near viewing, even though they may be able to converge. CONCLUSIONS: Taken together, our studies suggest that abnormal otolithic vestibular reflexes contribute to postural instability in PSP and cerebellar ataxia, and deserve further investigation. |
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Authors:
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Ke Liao; Mark F Walker; Anand C Joshi; Millard Reschke; Michael Strupp; Judith Wagner; R John Leigh |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Review |
Journal Detail:
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Title: Restorative neurology and neuroscience Volume: 28 ISSN: 1878-3627 ISO Abbreviation: Restor. Neurol. Neurosci. Publication Date: 2010 |
Date Detail:
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Created Date: 2010-01-20 Completed Date: 2010-04-06 Revised Date: 2013-04-10 |
Medline Journal Info:
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Nlm Unique ID: 9005499 Medline TA: Restor Neurol Neurosci Country: Netherlands |
Other Details:
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Languages: eng Pagination: 91-103 Citation Subset: IM |
Affiliation:
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Biomedical Engineering, Daroff-Dell'Osso Laboratory, Veterans Affairs Medical Center and University Hospitals, Case Western Reserve University, Cleveland, OH, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Accidental Falls* Cerebellar Ataxia / complications, physiopathology Gait Disorders, Neurologic / etiology, physiopathology* Humans Postural Balance / physiology* Psychomotor Performance / physiology Reflex, Abnormal / physiology Reflex, Vestibulo-Ocular / physiology* Supranuclear Palsy, Progressive / complications, physiopathology Vestibular Diseases / complications, physiopathology* Vestibular Function Tests |
| Grant Support | |
ID/Acronym/Agency:
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EY06717/EY/NEI NIH HHS; R01 EY006717-24/EY/NEI NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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