title: Noise-Enhanced Eversion Force Sense in Ankles With or Without Functional Instability.
abstract: BACKGROUND
  Force sense impairments are associated with functional ankle instability. Stochastic resonance stimulation (SRS) may have implications for correcting these force sense deficits.
  
  
  OBJECTIVE
  To determine if SRS improved force sense.
  
  
  METHODS
  Case-control study.
  
  
  METHODS
  Research laboratory.
  
  
  METHODS
  Twelve people with functional ankle instability (age = 23 ± 3 years, height = 174 ± 8 cm, mass = 69 ± 10 kg) and 12 people with stable ankles (age = 22 ± 2 years, height = 170 ± 7 cm, mass = 64 ± 10 kg).
  
  
  METHODS
  The eversion force sense protocol required participants to reproduce a targeted muscle tension (10% of maximum voluntary isometric contraction). This protocol was assessed under SRSon and SRSoff (control) conditions. During SRSon, random subsensory mechanical noise was applied to the lower leg at a customized optimal intensity for each participant.
  
  
  METHODS
  Constant error, absolute error, and variable error measures quantified accuracy, overall performance, and consistency of force reproduction, respectively.
  
  
  RESULTS
  With SRS, we observed main effects for force sense absolute error (SRSoff = 1.01 ± 0.67 N, SRSon = 0.69 ± 0.42 N) and variable error (SRSoff = 1.11 ± 0.64 N, SRSon = 0.78 ± 0.56 N) (P < .05). No other main effects or treatment-by-group interactions were found (P > .05).
  
  
  CONCLUSIONS
  Although SRS reduced the overall magnitude (absolute error) and variability (variable error) of force sense errors, it had no effect on the directionality (constant error). Clinically, SRS may enhance muscle tension ability, which could have treatment implications for ankle stability.
authors.affiliation: University of North Carolina at Greensboro.
authors.forename: Scott E
authors.initials: SE
authors.lastname: Ross
authors.affiliation: Georgia State University, Atlanta.
authors.forename: Shelley W
authors.initials: SW
authors.lastname: Linens
authors.affiliation: Whitworth University, Spokane, WA.
authors.forename: Cynthia J
authors.initials: CJ
authors.lastname: Wright
authors.affiliation: School of Health and Rehabilitation Sciences, Indiana University, Indianapolis.
authors.forename: Brent L
authors.initials: BL
authors.lastname: Arnold
mesh_terms: D016512:Ankle Injuries / Q000503:physiopathology*; D000843:Ankle Joint / Q000503:physiopathology; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D007593:Joint Instability / Q000503:physiopathology*; D008297:Male; D009129:Muscle Tonus / Q000502:physiology; D009622:Noise; D011434:Proprioception / Q000502:physiology*; D011897:Random Allocation; D014732:Vibration; D055815:Young Adult
keywords: chronic injuries; error; proprioception; sensorimotor system; stochastic resonance