To establish normative data in an Indian population forstatic and dynamic Subjective Visual Vertical andHorizontal (SVV & SVH) examination and to determinethe role of SVV & SVH in evaluation of patients withmigrainous vertigo

OBJECTIVES: To establish normative data for static and dynamic Subjective Visual Vertical and Horizontal (SVV & SVH) in Indian population and to evaluate its role as a screening tool for migranous vertigo patients. Another objective of our study was to analyse the otoneurological profile of migranous vertigo patients. METHODS: All patients presenting to the ENT opd in a tertiary care hospital who were diagnosed as migranous vertigo were recruited into the study group of migranous vertigo and the relatives of the patients who volunteered for SVV and SVH examination and were found to be clinically normal were recruited into the normal volunteer group. Six readings each for dynamic and static subjective vertical/horizontal were recorded and average means were calculated. The values of migranous vertigo patients were compared with the normative values calculated. RESULTS: The normative values were 1.49 degrees for static vertical, 1.92 degrees for dynamic vertical, 1.63 degrees for static horizontal and 1.94 degrees for dynamic horizontal. The corresponding values in migranous vertigo were significant for dynamic subjective visual vertical and dynamic subjective visual horizontal. The above suggested SVV/SVH to be good screening tool for migranous vertigo. CONCLUSION: NORMAL VOLUNTEER GROUP: 1. The normative values for static and dynamic SVV / SVH are as follows:- Static vertical:-1.49 degrees, Dynamic vertical:-1.92 degrees, Static horizontal:-1.63 degrees, Dynamic horizontal:-1.94degrees. 2. There was no statistically significant difference between the two age groups (20-40 years and 40-60 years) and their corresponding SVV and SVH values. 3. There were no male female differences that were statistically significant between the males and females and SVV and SVH values. 4. The normative values were comparable with those of the western literature. MIGRANOUS VERTIGO GROUP: 5. The average age of presentation for migranous vertigo patients was 29.7 and 48.6 in the respective age groups of 20-40 years and 40 to 60 years. The overall mean age was around 39.7 years. 6. The values for the subjective visual vertical and horizontal in both static and dynamic aspects for patients diagnosed with Migranous vertigo were as follows:- Static vertical:-1.46 degrees, Dynamic vertical:-3.02 degrees, Static horizontal:-1.87 degrees, Dynamic horizontal:-3.24 degrees. 7. The above values of dynamic SVV and dynamic SVH were significantly different when compared to the normative values. 8. Static SVH values were statistically significant in the age group of 40-60 years when compared to the corresponding normative values. 9. The values of dynamic SVV and dynamic SVH were not different among the two age groups and males/females upon statistical analysis in patients of migranous vertigo. 10. There was a female preponderance among patients with migranous vertigo. 11. Of 36 patients of migranous vertigo who had imaging, 8 had abnormalities that are considered non-specific by radiologists. 12. Electronystagmogram was done for 47 patients and 21 out of these were normal study whereas 26 patients had abnormal findings on ENG which is a significant finding suggesting involvement of vestibular pathways in \ patients diagnosed as Migranous vertigo. 13. The episodes of vertigo had durations lasting from as less as to a minute to hours. However, a majority of the patients complained of vertigo which was surrounding rotatory (81.8%) and lasting for few minutes (42.4% patients complained of episodes lasting less than 5 minutes). 14. A significant proportion of the patients diagnosed with Migranous vertigo had associated aura like phonophobia and photophobia (80.3%). 17. SVV and SVH can be an important test that can be added to the list of audiovestibular tests available for migranous vertigo patients.