Subsensory stochastic electrical stimulation targeting muscle afferents alters gait control during locomotor adaptations to haptic perturbations
Giacomo Severini,
Alexander Koenig,
Iahn Cajigas,
Nicholas Lesniewski-Laas,
James Niemi,
Paolo Bonato
Affiliations
Giacomo Severini
Department of Physical Medicine & Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA, USA; School of Electrical and Electronic Engineering, University College Dublin, Dublin, Dublin 4, Ireland; Centre for Biomedical Engineering, University College Dublin, Dublin, Dublin 4, Ireland; Corresponding author
Alexander Koenig
Department of Physical Medicine & Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA, USA
Iahn Cajigas
Department of Physical Medicine & Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA, USA; Department of Neurological Surgery, University of Pennsylvania, Philadelphia, PA, USA
Nicholas Lesniewski-Laas
Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
James Niemi
Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
Paolo Bonato
Department of Physical Medicine & Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
Summary: Subsensory noise stimulation targeting sensory receptors has been shown to improve balance control in healthy and impaired individuals. However, the potential for application of this technique in other contexts is still unknown. Gait control and adaptation rely heavily on the input from proprioceptive organs in the muscles and joints. Here we investigated the use of subsensory noise stimulation as a means to influence motor control by altering proprioception during locomotor adaptations to forces delivered by a robot. The forces increase step length unilaterally and trigger an adaptive response that restores the original symmetry. Healthy participants performed two adaptation experiments, one with stimulation applied to the hamstring muscles and one without. We found that participants adapted faster but to a lesser extent when undergoing stimulation. We argue that this behavior is because of the dual effect that the stimulation has on the afferents encoding position and velocity in the muscle spindles.
