Linked Life Data

15826988

Source:http://linkedlifedata.com/resource/pubmed/id/15826988

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
2005-4-13
pubmed:abstractText
Responses to pitch head impulses were measured in 15 patients with cerebellar degeneration and downbeat nystagmus and in 5 control subjects, using three-axis search coils. For each subject, response gains were calculated as (1) the ratio of instantaneous vertical eye velocity to pitch head velocity (at 30 ms and at 70 ms into the response), and (2) the ratio of peak eye velocity to peak head velocity. Gains varied more widely among patients. When calculated at 70 ms and using peak values, patients had higher gains for downward pitch, and normal subjects had symmetric gains. At 30 ms, gains were more symmetric in patients, but at that point control subjects actually had lower gains for downward pitch. Thus, the pitch gain ratio (ratio of downward gain to upward gain) was consistently greater in patients than in normal subjects. Because downward impulses were generally faster, eye velocities during downward and upward pitch for equivalent head speeds were also compared. Again, patients had higher gains for downward pitch. These results are consistent with the authors' hypothesis that cerebellar disease results in a higher sensitivity of anterior than posterior semicircular canal pathways, perhaps through loss of inhibition from the flocculus/paraflocculus complex on anterior canal secondary neurons in the vestibular nuclei. The pitch gain asymmetry was larger than, and did not correlate with, the velocity of spontaneous upward drift. This supports the notion that other mechanisms are likely to contribute to downbeat nystagmus in these patients.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0077-8923
pubmed:author
pubmed:issnType
Print
pubmed:volume
1039
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
349-58
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Asymmetry of the pitch vestibulo-ocular reflex in patients with cerebellar disease.
pubmed:affiliation
Department of Neurology, The Johns Hopkins University, 600 N. Wolfe Street, Pathology 2-210, Baltimore, MD 21287-6921, USA. mwalker@jhu.edu
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural