Document Detail

Phase-plane analysis of gaze stabilization to high acceleration head thrusts: a continuum across normal subjects and patients with loss of vestibular function.
MedLine Citation:
PMID:  14657187     Owner:  NLM     Status:  MEDLINE    
We investigated the vestibulo-ocular reflex (VOR) during high-acceleration, yaw-axis, head rotations in 12 normals and 15 patients with vestibular loss [7 unilateral vestibular deficient (UVD) and 8 bilateral vestibular deficient (BVD)]. We analyzed gaze stabilization within a 200-ms window after head rotation began, using phase planes, which allowed simultaneous analysis of gaze velocity and gaze position. These "gaze planes" revealed critical dynamic information not easily gleaned from traditional gain measurements. We found linear relationships between peak gaze-velocity and peak gaze-position error when normalized to peak head speed and position, respectively. Values fell on a continuum, increasing from normals, to normals tested with very high acceleration (VHA = 10,000-20,000 degrees/s2), to UVD patients during rotations toward the intact side, to UVD patients during rotations toward the lesioned side, to BVD patients. We classified compensatory gaze corrections as gaze-position corrections (GPCs) or gaze-velocity error corrections (GVCs). We defined patients as better-compensated when the value of their end gaze position was low relative to peak gaze position. In the gaze plane this criterion corresponded to relatively stereotyped patterns over many rotations, and appearance of high velocity (100-400 degrees/s) GPCs in the gaze plane ending quadrant (150-200 ms after head movement onset). In less-compensated patients, and normals at VHA, more GVCs were generated, and GPCs were generated only after gaze-velocity error was minimized. These findings suggest that challenges to compensatory vestibular function can be from vestibular deficiency or novel stimuli not previously experienced. Similar patterns of challenge and compensation were observed in both patients with vestibular loss and normal subjects.
Grace C Y Peng; David S Zee; Lloyd B Minor
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.     Date:  2003-12-03
Journal Detail:
Title:  Journal of neurophysiology     Volume:  91     ISSN:  0022-3077     ISO Abbreviation:  J. Neurophysiol.     Publication Date:  2004 Apr 
Date Detail:
Created Date:  2004-03-10     Completed Date:  2004-05-17     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0375404     Medline TA:  J Neurophysiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1763-81     Citation Subset:  IM    
Department of Neurology, The Johns Hopkins University, Baltimore, Maryland 21287, USA.
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MeSH Terms
Adaptation, Physiological
Aged, 80 and over
Eye Movements / physiology
Fixation, Ocular / physiology*
Functional Laterality
Head Movements / physiology*
Middle Aged
Nonlinear Dynamics
Reflex, Vestibulo-Ocular / physiology*
Time Factors
Vestibular Diseases / physiopathology*
Vestibular Function Tests
Grant Support
Erratum In:
J Neurophysiol. 2004 Sep;92(3):1963

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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