HAL® exoskeleton training improves walking parameters and normalizes cortical excitability in primary somatosensory cortex in spinal cord injury patients.
BACKGROUND
Reorganization in the sensorimotor cortex accompanied by increased excitability and enlarged body representations is a consequence of spinal cord injury (SCI). Robotic-assisted bodyweight supported treadmill training (BWSTT) was hypothesized to induce reorganization and improve walking function.


OBJECTIVE
To assess whether BWSTT with hybrid assistive limb® (HAL®) exoskeleton affects cortical excitability in the primary somatosensory cortex (S1) in SCI patients, as measured by paired-pulse somatosensory evoked potentials (ppSEP) stimulated above the level of injury.


METHODS
Eleven SCI patients took part in HAL® assisted BWSTT for 3 months. PpSEP were conducted before and after this training period, where the amplitude ratios (SEP amplitude following double pulses - SEP amplitude following single pulses) were assessed and compared to eleven healthy control subjects. To assess improvement in walking function, we used the 10-m walk test, timed-up-and-go test, the 6-min walk test, and the lower extremity motor score.


RESULTS
PpSEPs were significantly increased in SCI patients as compared to controls at baseline. Following training, ppSEPs were increased from baseline and no longer significantly differed from controls. Walking parameters also showed significant improvements, yet there was no significant correlation between ppSEP measures and walking parameters.


CONCLUSIONS
The findings suggest that robotic-assisted BWSTT with HAL® in SCI patients is capable of inducing cortical plasticity following highly repetitive, active locomotive use of paretic legs. While there was no significant correlation of excitability with walking parameters, brain areas other than S1 might reflect improvement of walking functions. EEG and neuroimaging studies may provide further information about supraspinal plastic processes and foci in SCI rehabilitation.
Department of Neurology, BG University Hospital Bergmannsheil Bochum, Ruhr-University Bochum, Bürkle-de-la-Camp-Platz 1, 44789, Bochum, Germany. matthias.sczesny-kaiser@rub.de.
Matthias
M
Sczesny-Kaiser
Department of Neurology, BG University Hospital Bergmannsheil Bochum, Ruhr-University Bochum, Bürkle-de-la-Camp-Platz 1, 44789, Bochum, Germany. oliver.hoeffken@rub.de.
Oliver
O
Höffken
Department of Spinal Cord Injuries, BG University Hospital Bergmannsheil Bochum, Ruhr-University Bochum, Bürkle-de-la-Camp-Platz 1, 44789, Bochum, Germany. mirko.aach@bergmannsheil.de.
Mirko
M
Aach
Department of General and Trauma Surgery, BG University Hospital Bergmannsheil, Ruhr-University Bochum, Bürkle-de-la-Camp-Platz 1, 44789, Bochum, Germany. oliver.cruciger@bergmannsheil.de.
Oliver
O
Cruciger
Department of General and Trauma Surgery, BG University Hospital Bergmannsheil, Ruhr-University Bochum, Bürkle-de-la-Camp-Platz 1, 44789, Bochum, Germany. dennis.grasmuecke@bergmannsheil.de.
Dennis
D
Grasmücke
Department of Spinal Cord Injuries, BG University Hospital Bergmannsheil Bochum, Ruhr-University Bochum, Bürkle-de-la-Camp-Platz 1, 44789, Bochum, Germany. renate.meindl@bergmannsheil.de.
Renate
R
Meindl
Department of General and Trauma Surgery, BG University Hospital Bergmannsheil, Ruhr-University Bochum, Bürkle-de-la-Camp-Platz 1, 44789, Bochum, Germany. thomas.schildhauer@bergmannsheil.de.
Thomas A
TA
Schildhauer
Department of Neurology, BG University Hospital Bergmannsheil Bochum, Ruhr-University Bochum, Bürkle-de-la-Camp-Platz 1, 44789, Bochum, Germany. peter.schwenkreis@rub.de.
Peter
P
Schwenkreis
Department of Neurology, BG University Hospital Bergmannsheil Bochum, Ruhr-University Bochum, Bürkle-de-la-Camp-Platz 1, 44789, Bochum, Germany. martin.tegenthoff@rub.de.
Martin
M
Tegenthoff
D000328:Adult; D055724:Electrophysiological Phenomena; D019054:Evoked Potentials, Motor; D005073:Evoked Potentials, Somatosensory; D005260:Female; D006801:Humans; D008124:Locomotion; D008297:Male; D008475:Median Nerve / Q000503:physiopathology; D008875:Middle Aged; D009473:Neuronal Plasticity; D009989:Orthotic Devices; D010865:Pilot Projects; D011474:Prosthesis Design; D012371:Robotics; D012656:Self-Help Devices; D013003:Somatosensory Cortex / Q000503:physiopathology*; D013119:Spinal Cord Injuries / Q000503:physiopathology* / Q000534:rehabilitation*; D016138:Walking