Abstract for presentation at The Australian and New Zealand Association of Neurologists Annual Scientific Meeting 2007

Chronic anti-epileptic drug treatment is associated with lower balance function scores - a twin and matched sibling AED-discordant pair study

  • Dr Sandra Petty, Department of Medicine, RMH, University of Melbourne, Australia
  • Ms Natalie El Haber, National Ageing Research Institute, Parkville, AND Department of Medicine, RMH, The University of Melbourne, Australia
  • Lynda Paton, Department of Medicine, RMH, University of Melbourne, Australia
  • A/Prof Terence O'Brien, Department of Neuroscience, The Royal Melbourne Hospital, and Department of Medicine, University of Melbourne, Australia
  • Prof Samuel Berkovic, Epilepsy Research Centre, Austin Health, Australia
  • A/Prof Keith Hill, National Ageing Research Institute, Parkville, Australia
  • Prof John Wark, Department of Medicine, RMH, University of Melbourne, Australia

    • Purpose: Anti-epileptic medication (AED) users have increased incidence of fractures. Potential causes for this association include bone disease and increased falls during seizure and at other times. This study aims to assess the effect of chronic AED usage on muscle strength and balance utilizing a twin and matched sibling AED-discordant pair approach.
    Methods: 20 AED-usage discordant pairs (13 female, 7 male) 3 monozygous, 5 dizygous, 12 sibling pairs (within 3 years of age) with mean(SD) age 47.0(16.9) years were assessed. Mean duration of AED use (for AED-users) was 22.6(16.9) years. Validated tests of static and dynamic balance (clinical and force platform tests), muscle strength, and gait which are predictive of falls risk were performed. Relevant serum AED levels were measured. Results were adjusted for height and weight where required.
    Results: There was no significant within-pair difference in age, height, weight, muscle strength, gait (velocity or double support duration) or maximum activity level. A significant mean within-pair difference (AED-user vs. non-user,) was seen with adjusted activity score (-7 points, p=0.012) and measures of balance, including: Chattecx Balance System (positive score indicating greater sway and therefore increased unsteadiness)- Stable Platform with distraction task (serial threes): Left-Right sway(LR)cm/Height +0.468, p=0.022; AP moving platform LRcm/height +0.509, p=0.016; Medial-Lateral(ML) moving platform with distraction LRcm/height +0.797, p=0.032; Single leg stance: Stable platform LRcm/height +0.685, p=0.039. Lord's balance test eyes closed +41mm, p=0.045, Coordinated stability track (n=14) +4.4 points, p=0.045.
    Conclusions: There is significant within-pair difference in balance function in chronic AED users compared to their matched twin/sibling control. This impairment of balance function may have important implications for AED users in terms of increased falls risk and may contribute to increased risk of fractures seen in this patient group.

    Conference Organiser - ICMS Pty Ltd