Nakanishi T1,2, Milosevic M1,2, Sasaki A1, Yamaguchi A1, Nakazawa K1
1The University of Tokyo, Graduate School of Arts and Science, Meguro-ku, Tokyo, Japan, 2Japan Society for the Promotion of Science, Kojimachi, Chiyoda-ku, Tokyo, Japan
Background: Functional electrical stimulation (FES) therapy (FET) [MM1] has been developed to promote functional recovery after neurological impairments / injuries using intensive training combined with electrical stimulation of muscles. Previously, clinical improvements have been reported in the upper limb motor function after stroke and spinal cord injury using FET. However, little is known about the mechanisms of FET on neural activation.
Purpose: To investigate brain functional changes over the course of 3 months of FET in a person with traumatic brain injury using functional MRI (fMRI) and transcranial magnetic stimulation (TMS).
Methods: A single subject (male; age: 39 years) with a traumatic brain injury (TBI) including symptoms of ataxia in the upper-limb was recruited in this study. FET was delivered using Complex Motion (Compex, Switzerland), a 4 channel, constant current FES system, which was used to activate muscles by applying a rectangular, biphasic, asymmetric charge balanced stimulation pulses at a 40 Hz stimulation frequency and 300 µsec pulse width. Electrical stimulation was applied on the muscles transcutaneously via surface electrodes. The training was performed 3 times per week over the period of 12 weeks. Assessments using fMRI, TMS and writing test were carried out before the intervention (Pre), every 6 weeks during the intervention (During and Post0) as well as after the intervention (Post1 and Post2). During fMRI assessments, participant performed hand grip force matching task. During TMS, using a figure-of-eight coil, single-pulse stimulation was delivered over the area of the left primary motor cortex (M1) that was optimal for inducing motor evoked potential (MEP) in the right FDI muscle.
Results: fMRI results showed that there was no significant activation in the motor area (M1) during the power grip task at Pre and During assessment. However, during Post 0, activity in the M1 area was increased . Furthermore, we showed that activations remained during Post 1 and Post2 assessments (i.e., for at least 3 months after the end of the intervention). This result revealed the neural effects of FET using functional brain imaging as an evaluation index. Moreover, in region-of-interest (ROI) analysis, not only was contralateral M1 activated as a result of FET, but also the sensory (S1), PR, SMA and PM are similarly activated. These are areas related to motor control and movement, and it is interesting that FET could also affect sensory areas. Finally TMS analysis revealed that inferior hand muscles were more activated after FET, and that the hand motor area expanded similarly to fMRI dat. In addition, drawing test revealed that the error and acceleration were decreased and tremors were alleviated in the writing performance test after FET training.
Conclusion(s): Changes in the fMRI and TMS data suggest that FET can be effective for increasing brain activity after unilateral FET, which required about three months of intervention / training.
Implications: Although it is only a single case result, this study presents strong evidence that FET can affect neural activations in multiple hand motor and sensory brain, which is likely responsible for improved motor function after FET.
Keywords: Functional electrical stimulation, brain plasticity, fMRI
Funding acknowledgements: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Purpose: To investigate brain functional changes over the course of 3 months of FET in a person with traumatic brain injury using functional MRI (fMRI) and transcranial magnetic stimulation (TMS).
Methods: A single subject (male; age: 39 years) with a traumatic brain injury (TBI) including symptoms of ataxia in the upper-limb was recruited in this study. FET was delivered using Complex Motion (Compex, Switzerland), a 4 channel, constant current FES system, which was used to activate muscles by applying a rectangular, biphasic, asymmetric charge balanced stimulation pulses at a 40 Hz stimulation frequency and 300 µsec pulse width. Electrical stimulation was applied on the muscles transcutaneously via surface electrodes. The training was performed 3 times per week over the period of 12 weeks. Assessments using fMRI, TMS and writing test were carried out before the intervention (Pre), every 6 weeks during the intervention (During and Post0) as well as after the intervention (Post1 and Post2). During fMRI assessments, participant performed hand grip force matching task. During TMS, using a figure-of-eight coil, single-pulse stimulation was delivered over the area of the left primary motor cortex (M1) that was optimal for inducing motor evoked potential (MEP) in the right FDI muscle.
Results: fMRI results showed that there was no significant activation in the motor area (M1) during the power grip task at Pre and During assessment. However, during Post 0, activity in the M1 area was increased . Furthermore, we showed that activations remained during Post 1 and Post2 assessments (i.e., for at least 3 months after the end of the intervention). This result revealed the neural effects of FET using functional brain imaging as an evaluation index. Moreover, in region-of-interest (ROI) analysis, not only was contralateral M1 activated as a result of FET, but also the sensory (S1), PR, SMA and PM are similarly activated. These are areas related to motor control and movement, and it is interesting that FET could also affect sensory areas. Finally TMS analysis revealed that inferior hand muscles were more activated after FET, and that the hand motor area expanded similarly to fMRI dat. In addition, drawing test revealed that the error and acceleration were decreased and tremors were alleviated in the writing performance test after FET training.
Conclusion(s): Changes in the fMRI and TMS data suggest that FET can be effective for increasing brain activity after unilateral FET, which required about three months of intervention / training.
Implications: Although it is only a single case result, this study presents strong evidence that FET can affect neural activations in multiple hand motor and sensory brain, which is likely responsible for improved motor function after FET.
Keywords: Functional electrical stimulation, brain plasticity, fMRI
Funding acknowledgements: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Topic: Neurology; Electrophysical & isothermal agents
Ethics approval required: Yes
Institution: The University of Tokyo
Ethics committee: Graduate School of Arts and Sciences
Ethics number: 581
All authors, affiliations and abstracts have been published as submitted.
