Jakob U Blicher1, Jørgen F Nielsen. 1. Hammel Neurorehabilitation and Research Centre, Aarhus University Hospital, Denmark. neujbl@sc.aaa.dk
Abstract
BACKGROUND: Recent studies have proposed a role for robotic gait training in participants with acquired brain injury, but the effects on the excitability of cortical and spinal neurons even in healthy participants are uncertain. OBJECTIVE: To investigate changes in corticospinal excitability in healthy participants after active and passive robotic gait training in a driven gait orthosis (DGO), the Lokomat. METHODS: Thirteen healthy participants took part in 2 experiments. Each participant performed 20 minutes of active and passive gait training in a DGO. Motor evoked potentials (MEP), short-interval intracortical inhibition (SICI), intracortical facilitation (ICF), F-wave frequency, and Mmax were measured in the right tibialis anterior muscle before and after training. RESULTS: Active training led to a decline in MEP amplitude and F-wave frequency. The MEP decline was associated with subjective muscle fatigue. Passive training induced a decrease in SICI lasting for 20 minutes after training. CONCLUSIONS: The decline in MEP after active training is most likely because of central fatigue, whereas the decreased F-wave frequency might represent short-term plastic changes in the spinal cord. The decrease in SICI after passive training probably reflects a decrease in intracortical GABA activity, which could benefit the acquisition of new motor skills.
BACKGROUND: Recent studies have proposed a role for robotic gait training in participants with acquired brain injury, but the effects on the excitability of cortical and spinal neurons even in healthy participants are uncertain. OBJECTIVE: To investigate changes in corticospinal excitability in healthy participants after active and passive robotic gait training in a driven gait orthosis (DGO), the Lokomat. METHODS: Thirteen healthy participants took part in 2 experiments. Each participant performed 20 minutes of active and passive gait training in a DGO. Motor evoked potentials (MEP), short-interval intracortical inhibition (SICI), intracortical facilitation (ICF), F-wave frequency, and Mmax were measured in the right tibialis anterior muscle before and after training. RESULTS: Active training led to a decline in MEP amplitude and F-wave frequency. The MEP decline was associated with subjective muscle fatigue. Passive training induced a decrease in SICI lasting for 20 minutes after training. CONCLUSIONS: The decline in MEP after active training is most likely because of central fatigue, whereas the decreased F-wave frequency might represent short-term plastic changes in the spinal cord. The decrease in SICI after passive training probably reflects a decrease in intracortical GABA activity, which could benefit the acquisition of new motor skills.
Authors: Andrew Jt Stevenson; Natalie Mrachacz-Kersting; Edwin van Asseldonk; Duncan L Turner; Erika G Spaich Journal: J Neuroeng Rehabil Date: 2015-09-17 Impact factor: 4.262