title: Effect of Focal Muscle Vibration on Calf Muscle Spasticity: A Proof-of-Concept Study.
abstract: Focal vibration has been studied for its ability to reduce spasticity in patients with upper motor neuron lesions, but adequate stimulation parameters remain unclear. Focal muscle vibration with adequate parameters may facilitate gait rehabilitation in patients with lower limb spasticity.
  
  
  
  To determine focal muscle vibration parameters that effectively inhibit the H-reflex of the gastrocnemius in healthy subjects.
  
  
  
  A proof-of-concept exploratory study.
  
  
  
  University hospital laboratory.
  
  
  
  Thirteen healthy volunteers.
  
  
  
  Focal muscle vibrations of 40, 80, and 120 Hz and amplitudes of 0.1, 0.3, and 0.5 mm were tested on the calf muscles of 10 healthy subjects, respectively. The H-reflex and M-response were recorded baseline, during vibration, and after vibration for each stimulation parameter. The mean vibratory inhibition index (VII) during vibration, the maximum amplitude of the H-reflex and M-response (Hmaxand Mmax), minimal onset latency of the H-reflex, and the ratio of Hmaxto Mmax(HMR) at each time point were measured.
  
  
  
  No significant difference was found among mean VIIs at 40, 80, and 120 Hz in the healthy subjects. However, a relatively consistent reduction of Hmaxand HMR was observed at 80 Hz. Mean VIIs at 0.3 and 0.5 mm were significantly lower than that at 0.1 mm (P < .001).
  
  
  
  This study suggests that focal muscle vibration may be an adjuvant therapy during gait rehabilitation in patients with calf muscle spasticity. Focal vibration at 80 Hz and 0.3 mm amplitude applied to the gastrocnemius effectively inhibits the segmental reflex pathway. A future clinical trial on this topic is warranted.
  
  
  
  II.
authors.affiliation: Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea(∗).
authors.forename: Han Gil
authors.initials: HG
authors.lastname: Seo
authors.affiliation: Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea(†).
authors.forename: Byung-Mo
authors.initials: BM
authors.lastname: Oh
authors.affiliation: Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea(‡).
authors.forename: Ja-Ho
authors.initials: JH
authors.lastname: Leigh
authors.affiliation: Center for Bionics, Biomedical Research Institute, Korea Institute of Science and Technology, Seoul, Republic of Korea(¶).
authors.forename: Changmook
authors.initials: C
authors.lastname: Chun
authors.affiliation: Center for Bionics, Biomedical Research Institute, Korea Institute of Science and Technology, Seoul, Republic of Korea(§).
authors.forename: Cheol
authors.initials: C
authors.lastname: Park
authors.affiliation: Center for Bionics, Biomedical Research Institute, Korea Institute of Science and Technology, Hwarang-ro 14-Gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea(∗∗). Electronic address: chkim@kist.re.kr.
authors.forename: Choong Hyun
authors.initials: CH
authors.lastname: Kim
mesh_terms: D004576:Electromyography; D006181:H-Reflex; D006801:Humans; D009128:Muscle Spasticity; D018482:Muscle, Skeletal; D026741:Physical Therapy Modalities; D014732:Vibration