Oculomotor strategies and their effect on reducing gaze position error.
OBJECTIVE
Vestibular adaptation exercises have been shown to improve gaze stability during active head rotation in individuals with vestibular hypofunction. Little is known, however, of the types of eye movements used during passive head rotation and their effect on gaze stability in individuals with vestibular hypofunction. The primary purpose of this study was to determine differences in oculomotor strategies and their effect on stabilizing gaze during ipsilesional passive and active head rotations in vestibular hypofunction.


METHODS
Subjects with unilateral (n = 4) and bilateral (n = 3) vestibular hypofunction and healthy subjects (n = 4) based on bithermal caloric and rotational chair testing.


METHODS
Diagnostic.


METHODS
Head and eye velocity and position data measured with scleral search coil.


RESULTS
Subjects with unilateral and bilateral vestibular hypofunction generated 3 types of gaze-stabilizing eye movements with ipsilesional head impulses: slow vestibular ocular reflex, compensatory, and corrective saccades. The types of eye movements generated during active and passive head impulses were highly individualized. Gaze position error was reduced when compensatory saccades were recruited as part of the gaze-stabilizing strategy.


CONCLUSIONS
Rehabilitation for individuals with vestibular hypofunction should identify individuals' unique gaze stability preferences and attempt to facilitate compensatory saccades.
Schubert
Michael C
MC
Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University, Baltimore, Maryland 21287, USA. mschube1@jhmi.edu
Hall
Courtney D
CD
Das
Vallabh
V
Tusa
Ronald J
RJ
Herdman
Susan J
SJ
D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003627:Data Interpretation, Statistical; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology*; D019416:Head Movements / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009801:Oculomotor Muscles / Q000502:physiology*; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology; D012399:Rotation; D012438:Saccades / Q000502:physiology; D015837:Vestibular Diseases / Q000503:physiopathology / Q000534:rehabilitation*