Vibratory noise to the fingertip enhances balance improvement associated with light touch

Autor(es)

Magalhaes, Fernando Henrique ^{[1, 2]} ; Kohn, Andre Fabio ^{[1, 2]}

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Neurosci Program, EPUSP, PTC, Sao Paulo, SP - Brazil

^[2] Univ Sao Paulo, Biomed Engn Lab, EPUSP, PTC, Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Experimental Brain Research; v. 209, n. 1, p. 139-151, Mar. 2011.
• Área do conhecimento: Engenharias - Engenharia Biomédica
• Citações Web of Science: 27
• Assunto(s): Sistema nervoso central Fisioterapia Terapia por estimulação elétrica Postura

Resumo

Light touch of a fingertip on an external stable surface greatly improves the postural stability of standing subjects. The hypothesis of the present work was that a vibrating surface could increase the effectiveness of fingertip signaling to the central nervous system (e.g., by a stochastic resonance mechanism) and hence improve postural stability beyond that achieved by light touch. Subjects stood quietly over a force plate while touching with their right index fingertip a surface that could be either quiescent or randomly vibrated at two low-level noise intensities. The vibratory noise of the contact surface caused a significant decrease in postural sway, as assessed by center of pressure measures in both time and frequency domains. Complementary experiments were designed to test whether postural control improvements were associated with a stochastic resonance mechanism or whether attentional mechanisms could be contributing. A full curve relating body sway parameters and different levels of vibratory noise resulted in a U-like function, suggesting that the improvement in sway relied on a stochastic resonance mechanism. Additionally, no decrease in postural sway was observed when the vibrating contact surface was attached to the subject’s body, suggesting that no attentional mechanisms were involved. These results indicate that sensory cues obtained from the fingertip need not necessarily be associated with static contact surfaces to cause improvement in postural stability. A low-level noisy vibration applied to the contact surface could lead to a better performance of the postural control system. (AU)

• Processo FAPESP: 07/03608-9 - Efeito de TENS e vibração sobre o controle postural humano
• Beneficiário: Fernando Henrique Magalhães
• Modalidade de apoio: Bolsas no Brasil - Doutorado