Zhi Wang MD, Presenter: Nothing to Disclose

Min Chen MD,PhD, Abstract Co-Author: Nothing to Disclose

Xia Gong MD, Abstract Co-Author: Nothing to Disclose

Cheng Zhou MD, Abstract Co-Author: Nothing to Disclose

To study the functional cortical regions with caloric stimulation with 0℃ water, using the BOLD-fMRI technique and to evaluate the value of this method in the functional localization of human vestibular cortex.

Twenty right-handed normal human volunteers, 12 males and 8 females, age 25 to 39 with no clinical abnormality in hearing and with normal otoscopic examinations, pure-tone audiometry and tympanometry tests, were examined with a recording electronystagmograph before fMRI scanning to confirm that the caloric stimulus actually induced vestibular nystagmus. During the electronystagmograph test, 15 ml cold water(0℃) was injected into the right ear of each volunteer over a 15s time period with the subject's eyes open. Functional images of brain were acquired on a 1.5T system. All the subjects were blindfolded with eyes open in a darkened room. The caloric stimulation during the fMRI scan was the same as the one with the electronystagmograph test. All data were analyzed on single-subject level and group level using SPM99(Statistical Paramatric Mapping99) in which both activation and deactivation were analyzed.

Vestibular dizziness and left-sided vestibular nystagmus occurred in each volunteer after injecting the cold water; however. the dizziness didn’t occur immediately after the injection of cold water either in the preliminary experiment or during the fMRI scan. Three of the twenty subjects' results were excluded because their head movement was more than 2mm. In the group analysis, three regions of activation in vestibular dizziness and three regions of the deactivated regions of cold water overlapped: 1.SEF (Supplementary Eye Field); 2. MT/MST (Middle Temporal Area/Medial Superior Temporal Area); 3. V1 (the primary visual area).

The activation and deactivation model of the three regions, including SEF, MT/MST and V1, showed that they participated in the processing of the delayed vestibular vertigo This provides evidence that these regions are important in vestibular function.

The mechanism and the cause of vertigo are unclear now. We can know more about it through this experiment.

Wang, Z, Chen, M, Gong, X, Zhou, C, Why the Cold Water Delayed the Onset of the Vestibular Vertigo: An fMRI Study.  Radiological Society of North America 2006 Scientific Assembly and Annual Meeting, November 26 - December 1, 2006 ,Chicago IL. http://archive.rsna.org/2006/4428818.html