CORRELATION OF IMPAIRED SUBJECTIVE VISUAL VERTICAL AND DISABILITY DEGREE IN MS PATIENTS.

Visual perception of verticality constitutes an important component of balance. A subjective visual vertical (SVV) test can reflect impairment of graviceptive pathways and can evaluate this sense with accuracy. Although the Expanded Disability Status Scale (EDSS) is considered the gold standard assessment for disability in Multiple Sclerosis (MS), it is known to be insensitive to detecting subtle functional impairments, such as balance complaints. SVV could be used to test these subtle balance complaints. Objectives: To compare SVV tilt in two MS groups divided according to balance complaints and to assess if the degree of disability (EDSS) is correlated to increased SVV tilt. Patients and Methods: Ninety-eight outpatients were recruited with a diagnosis of relapsing-remitting MS and an EDSS score between 0 - 4.5. They were divided into two groups: no balance complaints (NC) and balance complaints (IC). SVV perception was tested using a 30cm long luminous portable rod in a dark room in order to eliminate any visual reference cues. The rod was positioned at a 30 degree oblique angle in the frontal plane and then moved to the left and right 10 times. The subject was instructed to notify each time they believed the rod to be in a vertical position. The median of absolute values was considered, with an accuracy of 1 degree. Statistical analysis was performed using the Mann-Whitney test to compare the median of SVV deviations between MS groups, and Spearman's test to assess the correlation between SVV values and EDSS scores. Results: MS patients with balance complaints showed an increase of SVV tilt (p=0.003). The correlation between SVV deviation and EDSS also proved significant, thus patients with more disability showed worse perception of verticality (Spearman's correlation, r = 0.330, P < 0.001). Conclusion: MS patients with balance complaints have impaired perception of verticality, as measured by the SVV test. SVV tilt may be a sensitive sign for use in evaluating and following disability degree. [ABSTRACT FROM AUTHOR]