title: A shoe insole delivering subsensory vibratory noise improves balance and gait in healthy elderly people.
abstract: OBJECTIVE
  To test whether subsensory vibratory noise applied to the sole of the foot using a novel piezoelectric vibratory insole can significantly improve sensation, enhance balance, and reduce gait variability in elderly people, as well as to determine the optimal level of vibratory noise and whether the therapeutic effect would endure and the user's sensory threshold would remain constant during the course of a day.
  
  
  METHODS
  A randomized, single-blind, crossover study of 3 subsensory noise stimulation levels on 3 days.
  
  
  METHODS
  Balance and gait laboratory.
  
  
  METHODS
  Healthy community-dwelling elderly volunteers (N=12; age, 65-90y) who could feel the maximum insole vibration.
  
  
  METHODS
  A urethane foam insole with the piezoelectric actuators delivering subsensory vibratory noise stimulation to the soles of the feet.
  
  
  METHODS
  Balance, gait, and timed Up and Go (TUG) test.
  
  
  RESULTS
  The vibratory insoles significantly improved performance on the TUG test, reduced the area of postural sway, and reduced the temporal variability of walking at both 70% and 85% of the sensory threshold and during the course of a day. Vibratory sensation thresholds remained relatively stable within and across study days.
  
  
  CONCLUSIONS
  This study provides proof of concept that the application of the principle of stochastic resonance to the foot sole sensory system using a new low-voltage piezoelectric technology can improve measures of balance and gait that are associated with falls. Effective vibratory noise amplitudes range from 70% to 85% of the sensory threshold and can be set once daily.
authors.affiliation: Hebrew SeniorLife, Institute for Aging Research, Boston, MA; Beth Israel Deaconess Medical Center, Boston, MA; Harvard Medical School, Boston, MA. Electronic address: lipsitz@hsl.harvard.edu.
authors.forename: Lewis A
authors.initials: LA
authors.lastname: Lipsitz
authors.affiliation: Hebrew SeniorLife, Institute for Aging Research, Boston, MA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Lough
authors.affiliation: Harvard Medical School, Boston, MA; Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, MA.
authors.forename: James
authors.initials: J
authors.lastname: Niemi
authors.affiliation: Hebrew SeniorLife, Institute for Aging Research, Boston, MA; Beth Israel Deaconess Medical Center, Boston, MA; Harvard Medical School, Boston, MA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Travison
authors.affiliation: Merck Sharp and Dohme Consumer Care, Inc, Memphis, TN.
authors.forename: Harold
authors.initials: H
authors.lastname: Howlett
authors.affiliation: Hebrew SeniorLife, Institute for Aging Research, Boston, MA; Beth Israel Deaconess Medical Center, Boston, MA; Harvard Medical School, Boston, MA.
authors.forename: Brad
authors.initials: B
authors.lastname: Manor
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018592:Cross-Over Studies; D056228:Feedback, Sensory; D005260:Female; D005684:Gait / Q000502:physiology*; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D009622:Noise; D004856:Postural Balance / Q000502:physiology*; D012682:Sensory Aids; D012684:Sensory Thresholds; D012775:Shoes; D016037:Single-Blind Method; D014732:Vibration / Q000627:therapeutic use*
keywords: Aging; Gait; Noise; Postural balance; Rehabilitation; Sensory aids; Sensory feedback; Sensory thresholds; Shoes; Vibration