title: Substantial burden of dizziness in multiple sclerosis.
abstract: OBJECTIVE
  Dizziness affects 49-59% of persons with MS but few prior studies examined the impact of dizziness in persons with multiple sclerosis (MS). Using the North American Research Committee on Multiple Sclerosis (NARCOMS) Registry, we examined the measurement properties of the Dizziness Handicap Inventory (DHI) in persons with MS, and the association between the DHI and health-related quality of life (HRQOL).
  
  
  METHODS
  In 2004, NARCOMS participants completed the DHI. We scored the DHI for each participant and evaluated the association of the DHI scores and the participant demographic and clinical characteristics of interest using t-tests and Kruskal-Wallis tests as appropriate. We examined the association between the DHI scores and HRQOL (PCS-12, MCS-12) and disability status using Spearman rank correlations and generalized linear models.
  
  
  RESULTS
  8123 participants completed the questionnaire, of whom 74.5% were women and 96.6% were white. Their mean (SD) age of symptom onset was 30.3 (9.7) years and median (IQR) score on Patient Determined Disease Steps (PDDS) was 4 (1-6). The median (interquartile range) DHI score was 20 (0-44). The impact of dizziness could be classified as mild in over 60% of participants (n=4660), moderate in 30.9% (n=2340) and severe in 7.55% (n=572). The odds of reporting moderate or severe dizziness were reduced with higher socioeconomic status (post-graduate degree vs. less than high school education odds ratio [OR] 0.38; 95% confidence interval [CI]: 0.28-0.52) and increased with higher levels of disability (severe vs. mild disability OR 1.38; 95% CI: 1.13-1.68). Physical and mental HRQOL decreased as the impact of dizziness increased (DHI-PCS-12 r=-0.34, DHI-MCS-12 r=-0.37).
  
  
  CONCLUSIONS
  Dizziness is common in MS and adversely impacts quality of life. More effective management of this symptom may improve HRQOL and deserves more attention.
authors: Departments of Internal Medicine and Community Health Sciences, University of Manitoba, Winnipeg, CAN. Electronic address: rmarrie@hsc.mb.ca.
authors: Ruth Ann
authors: RA
authors: Marrie
authors: Department of Biostatistics, University of Alabama at Birmingham, Birmingham, USA.
authors: Gary R
authors: GR
authors: Cutter
authors: Division of Neurology, Barrow Neurological Institute, Phoenix, USA.
authors: Tuula
authors: T
authors: Tyry
keywords: Dizziness; Dizziness Handicap Inventory; Multiple sclerosis; Quality of life; Validation; Vertigo