Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2007-11-2
pubmed:abstractText
Alexander's law (AL) states that the slow-phase velocity of spontaneous nystagmus of peripheral vestibular origin is dependent on horizontal gaze position, with greater velocity when gaze is directed in the fast-phase direction. AL is thought to be a compensatory reaction resulting from adaptive changes in the horizontal ocular motor neural integrator. Until now, only horizontal eye movements have been investigated with respect to AL. Because spontaneous nystagmus usually includes vertical and torsional components, we asked whether horizontal gaze changes would have an effect on the 3D drift of spontaneous nystagmus and, thus, on the vertical/torsional neural integrator. We hypothesized that AL reduces all nystagmus components proportionally. Moreover, we questioned the classical theory of a single bilaterally organized horizontal integrator and searched for nonlinearities of AL implying a network of multiple integrators. Using dual scleral search coils, we measured AL in 17 patients with spontaneous nystagmus. Patients followed a pulsed laser dot at eye level jumping in 5 degrees steps along the horizontal meridian between 25 degrees right and left in otherwise complete darkness. AL was observed in 15 of 17 patients. Whereas individual patients typically showed a change of 3D-drift direction at different horizontal eye positions, the average change in direction was not different from zero. The strength of AL (= rate of change of total velocity with gaze position) correlated with nystagmus slow-phase velocity (Spearman's rho = 0.5; p < 0.05) and, on average, did not change the 3D nystagmus drift direction. In general, eye velocity did not vary linearly with eye position. Rather, there was a stronger dependence of velocity on horizontal position when subjects looked in the slow-phase direction compared to the fast-phase direction. We conclude that the theory of a simple leak of a single horizontal neural integrator is not sufficient to explain all aspects of AL.
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/17879115-10687930, http://linkedlifedata.com/resource/pubmed/commentcorrection/17879115-11403796, http://linkedlifedata.com/resource/pubmed/commentcorrection/17879115-11552001, http://linkedlifedata.com/resource/pubmed/commentcorrection/17879115-12325227, http://linkedlifedata.com/resource/pubmed/commentcorrection/17879115-12505606, http://linkedlifedata.com/resource/pubmed/commentcorrection/17879115-1342392, http://linkedlifedata.com/resource/pubmed/commentcorrection/17879115-14121113, http://linkedlifedata.com/resource/pubmed/commentcorrection/17879115-1455706, http://linkedlifedata.com/resource/pubmed/commentcorrection/17879115-15675005, http://linkedlifedata.com/resource/pubmed/commentcorrection/17879115-16088383, http://linkedlifedata.com/resource/pubmed/commentcorrection/17879115-1670152, http://linkedlifedata.com/resource/pubmed/commentcorrection/17879115-17369822, http://linkedlifedata.com/resource/pubmed/commentcorrection/17879115-2321369, http://linkedlifedata.com/resource/pubmed/commentcorrection/17879115-3390028, http://linkedlifedata.com/resource/pubmed/commentcorrection/17879115-3660642, http://linkedlifedata.com/resource/pubmed/commentcorrection/17879115-4713917, http://linkedlifedata.com/resource/pubmed/commentcorrection/17879115-5302604, http://linkedlifedata.com/resource/pubmed/commentcorrection/17879115-6441510, http://linkedlifedata.com/resource/pubmed/commentcorrection/17879115-6661444, http://linkedlifedata.com/resource/pubmed/commentcorrection/17879115-6745975, http://linkedlifedata.com/resource/pubmed/commentcorrection/17879115-8299746
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1525-3961
pubmed:author
pubmed:issnType
Print
pubmed:volume
8
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
551-61
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Alexander's law in patients with acute vestibular tone asymmetry--evidence for multiple horizontal neural integrators.
pubmed:affiliation
Department of Otorhinolaryngology, Head and Neck Surgery, Zurich University Hospital, Frauenklinikstr. 24, Ch-8091, Zurich, Switzerland.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't