This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.
Abstract
Objective: To study gaze in SCA-6 patients during pursuit and passive whole-body rotation.
Background: Smooth pursuit and vestibularly induced eye movements interact to maintain the accuracy of eye movements in space (i.e., gaze). Previous studies have implicated the cerebellum, particularly the floccular lobe and dorsal vermis, in the control of gaze velocity during pursuit and vestibulo-ocular reflex (VOR) cancellation. SCA-6 has recently been identified genetically and characterized as pure cerebellar ataxia that affects the cerebellar cortex selectively.
Methods: Using infrared oculography, eye movements of five SCA-6 patients and five age-matched normal control subjects were recorded during sinusoidal pursuit and passive whole-body rotation in the horizontal plane (amplitude, ±10 deg; frequency, 0.2 Hz). Eye and gaze gain (eye and gaze velocity/stimulus velocity) were calculated after deleting saccades.
Results: Eye gain of all SCA-6 patients during pursuit was significantly lower than those of the control subjects (mean ± SD, 0.26 ± 0.06 versus 0.91 ± 0.07). In contrast, eye gain of the patients was not significantly different from that of the control subjects either during VOR cancellation, when the subjects tracked a target that moved with the same amplitude and phase, like a chair (0.21 ± 0.05 versus 0.12 ± 0.07), or during visually enhanced VOR (×1), when the target remained stationary in space (0.85 ± 0.06 versus 0.95 ± 0.05). Moreover, there was no significant difference in mean VOR gain in total darkness between the two groups. Gaze gain of patients (0.26 ± 0.06 versus 0.81 ± 0.06) but not control subjects (0.91 ± 0.07 versus 0.88 ± 0.08), was significantly different during pursuit and VOR cancellation.
Conclusion: SCA-6 patients show dissociation in the control of gaze tracking during smooth pursuit and VOR cancellation.
- Received July 20, 1999.
- Accepted October 1, 1999.
AAN Members
We have changed the login procedure to improve access between AAN.com and the Neurology journals. If you are experiencing issues, please log out of AAN.com and clear history and cookies. (For instructions by browser, please click the instruction pages below). After clearing, choose preferred Journal and select login for AAN Members. You will be redirected to a login page where you can log in with your AAN ID number and password. When you are returned to the Journal, your name should appear at the top right of the page.
AAN Non-Member Subscribers
Purchase access
Letters: Rapid online correspondence
REQUIREMENTS
You must ensure that your Disclosures have been updated within the previous six months. Please go to our Submission Site to add or update your Disclosure information.
Your co-authors must send a completed Publishing Agreement Form to Neurology Staff (not necessary for the lead/corresponding author as the form below will suffice) before you upload your comment.
If you are responding to a comment that was written about an article you originally authored:
You (and co-authors) do not need to fill out forms or check disclosures as author forms are still valid
and apply to letter.
Submission specifications:
- Submissions must be < 200 words with < 5 references. Reference 1 must be the article on which you are commenting.
- Submissions should not have more than 5 authors. (Exception: original author replies can include all original authors of the article)
- Submit only on articles published within 6 months of issue date.
- Do not be redundant. Read any comments already posted on the article prior to submission.
- Submitted comments are subject to editing and editor review prior to posting.
You May Also be Interested in
Hastening the Diagnosis of Amyotrophic Lateral Sclerosis
Dr. Brian Callaghan and Dr. Kellen Quigg