Background and Objectives: Orthostatic dizziness (OD) is defined as when
dizziness is provoked by standing up from a supine or sitting position. It is usually
considered as being associated with orthostatic hypotension (OH). On the other
hand, it is recently suggested that otolith organ dysfunction and impaired
vestibulosympathetic reflex may account for development of OH and OD.
Vestibular evoked myogenic potential (VEMP) and subjective visual vertical and
horizontal tests (SVV/SVH) are tools for detecting otolith organ dysfunction. We
assessed cervical VEMP (cVEMP) and SVV/SVH test results in the patients with
OD to evaluate the relationship between OD and otolith organ function. Materials
and Methods: Three hundred-eighty-seven patients who visited dizziness clinic
were enrolled in this study. Seventy-three patients presented with OD (i.e., group
O), while 314 patients did not present OD (i.e., group N). Vestibular function
tests including cVEMP and SVV/SVH were performed. Results: cVEMP showed
abnormal response in 47.9% of group O and 60.2% of group N. Abnormal SVV
was found in 35.6% of group O and 31.5% of group N. Abnormal SVH was
highly found in both group O and group N (30.1%, 27.1%). Conclusion: The
values of SVV/SVH and cVEMP abnormality from both groups were not
significantly different between the groups O and N. This finding suggests that
otolithic function may not be related with OD.
Background and Objectives Subjective visual vertical (SVV) and subjective visual horizontal (SVH) are well known otolith function tests. Patients with acute unilateral vestibular weakness have a tendency to set the bar toward the side of the lesion in SVV and SVH tests. The object of this article is to identify the effect of preset angle on SVV and SVH tests in normal subjects and patients with dizziness.
Materials and Methods From October 2008 to March 2009, thirty healthy volunteers, twenty eight vestibular neuritis (VN) patients (14-uncompensated, 14-compensated), Twenty five patients who had migrainous vertigo (MV) were enrolled. All subjects performed the test two times in each of the clockwise and counter-clockwise preset angle.
Results In normal subjects, there was significant influence by preset angle on SVV test, not on SVH test. In VN patients with nystagmus, both SVH and SVV were not influenced by preset angle. In VN patients without nystagmus and in MV patients, there were significant influence by preset angle on both SVV and SVH tests.
Conclusion SVV and SVH values depend on the direction of the preset angle in MV and uncompensated VN patients. The preset angle should be considered in the interpretation of SVV and SVH values.
Background and Objectives Subject visual vertical (SVV) and subject visual horizontal (SVH) is well known otolith function test. Patients with acute unilateral vestibular weakness fail to set the test bar within normal range in SVH/SVV showing abnormal deviation toward lesion side. In some cases, SVH and SVV are deviated towards different directions, and analysis of these findings is rarely reported. The authors analyzed correlation of SVH/SVV and other vestibular function tests in patients with various vestibular diseases.
Materials and Methods From April 2005 to July 2007, total 234 patients who had admitted for dizziness were enrolled. All patients were divided in two groups, non-dissociation group (n=215) and dissociation group (n=19). Correlation of SVH, SVV, Videonystagmography (VNG), the rotating chair test was compared.
Results 8.1% of patients showed dissociation between SVH and SVV. Clinical features did not showed significant difference between groups. In non-dissociation group, SVH/SVV showed correlation with VNG, rotating chair test. However in dissociation group, VNG and rotating chair test revealed high rate of consistency with deviation of SVH than that of SVV. Also direction of SVH and dizziness had higher consistency (88.9%) than that of SVV (11.1%).
Conclusion The SVH showed consistency with other vestibular function test and may be more reliable than SVV when the result is dissociated.
Key Words: Subjective visual vertical; Subjective visual horizontal; Dissociation