title: Balance dysfunction in hereditary and spontaneous spastic paraparesis.
abstract: OBJECTIVE
  To determine how postural sway is affected in people with spastic paraparesis (pwSP) and the impact of different impairments.
  
  
  METHODS
  In 20 pwSP and 18 matched healthy controls standing postural sway was measured with eyes open and closed. Vibration threshold, isometric ankle and hip muscle strength and ankle stiffness with the participant at rest or preactivating the muscle was measured.
  
  
  RESULTS
  Antero-posterior (AP) and medio-lateral (ML) sway was higher in pwSP. Muscle strength was reduced and ankle stiffness increased in pwSP. Increased vibratory threshold was seen in 35% of participants. Higher total ankle stiffness (R2=0.44) was associated with lower AP sway with eyes open whilst hip abductor weakness was associated with increased ML sway with eyes open (R2=0.36) or closed (R2=0.47) or AP sway with the eyes closed (R2=0.48).
  
  
  CONCLUSIONS
  The degree of postural sway was related to muscle paresis of the hip abductors particularly in the ML direction and under conditions of reduced sensory input. People with higher total ankle stiffness have less AP sway suggesting that this may help to stabilise the body.
authors.affiliation: School of Health Professions, Peninsula Allied Health Centre, University of Plymouth, Derriford Road, Plymouth PL6 8BH, United Kingdom. Electronic address: jonathan.marsden@plymoutth.ac.uk.
authors.forename: Jon
authors.initials: J
authors.lastname: Marsden
authors.forename: Valerie
authors.initials: V
authors.lastname: Stevenson
mesh_terms: D000328:Adult; D000843:Ankle Joint / Q000503:physiopathology; D016022:Case-Control Studies; D005260:Female; D006621:Hip Joint / Q000503:physiopathology; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000503:physiopathology*; D020336:Paraparesis, Spastic / Q000235:genetics / Q000503:physiopathology*; D004856:Postural Balance / Q000502:physiology*
keywords: Balance; Hereditary spastic paraparesis; Paresis; Postural sway; Spasticity; Stiffness