Traditionally, results from caloric testing and optokinetic nystagmus (OKN) testing are analyzed separately because caloric testing is a measure of peripheral function and OKN testing is considered to be a measure of central function. However, there is a connection between the visual system and the vestibular system in the vestibular nucleus of the brainstem. The purpose of this paper was to determine whether a relationship exists between optokinetic nystagmus results and unilateral caloric weakness results. This was determined by conducting a retrospective study of forty patients who exhibited a unilateral caloric weakness greater than or equal to twenty percent and symptoms consistent with an uncompensated vestibulopathy. Patients were later divided into two groups based on involved side. A control group consisting of ten subjects with no reported hearing or vestibular problems was also recruited. When the data of all subjects with a unilateral caloric weakness was considered together, no correlation was found between caloric response (right and left ear) and optokinetic results (gain and slow phase velocity). However, a potential trend emerged at the slow stimulus velocity (15 degrees) when comparing the patients with a right caloric weakness to those with a left caloric weakness. Subjects with a right caloric weakness showed decreased OKN gain for the right eye with a right-moving stimulus compared to the subjects with a left caloric weakness. Alternatively, subjects with a left caloric weakness showed decreased OKN gain for the left eye with a left-moving stimulus compared to the subjects with a right caloric weakness. We conclude that interpretation of OKN along with caloric results may offer potential for identification and tracking of compensation after a unilateral loss of vestibular function, but further research is needed.
| Identifer | oai:union.ndltd.org:USF/oai:scholarcommons.usf.edu:etd-2003 |
| Date | 01 December 2003 |
| Creators | Cyr, D'Arcy D |
| Publisher | Scholar Commons |
| Source Sets | University of South Flordia |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Graduate Theses and Dissertations |
| Rights | default |
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