Light touch modulates balance recovery following perturbation: from fast response to stance restabilization

Author(s)

Martinelli, Alessandra Rezende ^[1] ; Coelho, Daniel Boari ^[1] ; Magalhaes, Fernando Henrique ^[2] ; Kohn, Andre Fabio ^[2] ; Teixeira, Luis Augusto ^[1]

Affiliation

^[1] Univ Sao Paulo, Human Motor Syst Lab, Sch Phys Educ & Sport, BR-05508030 Sao Paulo, SP - Brazil

^[2] Univ Sao Paulo, Biomed Engn Lab, Escola Politecn, BR-05586060 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: Experimental Brain Research; v. 233, n. 5, p. 1399-1408, MAY 2015.
• Web of Science Citations: 7

Abstract

Light fingertip touch of a static bar generates extra somatosensory information used by the postural control system to reduce body sway. While the effect of light touch has been studied in quiet stance, less attention has been given to its potential benefit for reactive postural responses. In the present study, we tested the effect of light fingertip touch of a stable surface on recovery of postural stability from a mechanical perturbation. Participants stood upright on a force plate touching a static rigid bar while being pulled backward by a load. Unpredictable release of the load induced fast anterior body sway, requiring a reactive response to recover balance. Effect of light touch on postural responses was assessed as a function of vision and malleability of the support surface, analyzing different epochs ranging from the pre-perturbation period to recovery of a relatively stable quiet stance. Results showed that light touch induced lower magnitude of muscular activation in all epochs. Center of pressure (CoP) displacement/sway was affected by interaction of light touch with manipulation of the other sensory information. For the periods associated with quiet stance, light touch led to decreased CoP sway in the malleable surface in the pre-perturbation epoch, and in the condition combining no vision and malleable surface in the balance restabilization and follow-up quiet stance epochs. For the fast reactive response epoch, light touch induced smaller amplitude of CoP displacement across conditions, and lower CoP maximum velocity in the condition combining no vision and rigid surface. These results showed that light touch modulates postural responses in all epochs associated with an unanticipated mechanical perturbation, with a more noticeable effect in conditions manipulating sensory information relevant for balance control. (AU)

• FAPESP's process: 11/18173-3 - Postural responses to external perturbation in post-stroke: rehabilitation and improvement of stability by touching a vibrating surface
• Grantee: Alessandra Rezende Martinelli Conterato
• Support type: Scholarships in Brazil - Doctorate
• FAPESP's process: 13/00639-1 - Postural responses to extrinsic perturbation and sensory constraint post-stroke: effect of additional tactile information
• Grantee: Luis Augusto Teixeira
• Support type: Regular Research Grants
• FAPESP's process: 11/13222-6 - EVALUATION OF INHIBITORY PATHWAYS AND THE EFFECT OF ELECTRICAL NOISE STIMULATION ON PLANTAR FLEXION NEUROMUSCULAR CONTROL
• Grantee: Fernando Henrique Magalhães
• Support type: Scholarships in Brazil - Post-Doctorate