Affiliations: Abteilung Klinische Neurophysiologie, Georg-August
Universität Göttingen, Göttingen, Germany | Biomedizinische NMR Forschungs GmbH am
Max-Planck-Institut für biophysikalische Chemie, Göttingen,
Germany | Otto Bock HealthCare Deutschland GmbH, Duderstadt,
Germany
Note: [] Corresponding author: Prof. Dr. med. Walter Paulus, Abteilung
klinische Neurophysiologie, Universität Göttingen, Robert-Koch Str. 40,
37075 Göttingen, Germany. Tel.: +49 (0)551 39 6650; Fax: +49 (0)551 39
8126; E-mail: wpaulus@med.uni-goettingen.de
Abstract: Purpose: EMG-triggered electrostimulation (EMG-ES) may improve the
motor performance of affected limbs of hemiparetic stroke patients even in the
chronic stage. This study was designed to characterize cortical activation
changes following intensified EMG-ES in chronic stroke patients and to identify
predictors for successful rehabilitation depending on disease severity. Methods: We studied 9 patients with severe residual
hemiparesis, who underwent 8 weeks of daily task-orientated multi-channel
EMG-ES of the paretic arm. Before and after treatment, arm function was
evaluated clinically and cortical activation patterns were assessed with
functional MRI (fMRI) and/or transcranial magnetic stimulation (TMS). Results: As response to therapy, arm function improved in a
subset of patients with more capacity in less affected subjects, but there was
no significant gain for those with Box & Block test values below 4 at
inception. The clinical improvement, if any, was accompanied by an ipsilesional
increase in the sensorimotor cortex (SMC) activation area in fMRI and enhanced
intracortical facilitation (ICF) as revealed by paired TMS. The SMC activation
change in fMRI was predicted by the presence or absence of motor-evoked
potentials (MEPs) on the affected side. Conclusions: The present findings support the notion that
intensified EMG-ES may improve the arm function in individual chronic
hemiparetic stroke patients but not in more severely impaired individuals.
Functional improvements are paralleled by increased ipsilesional SMC activation
and enhanced ICF supporting neuroplasticity as contributor to rehabilitation.
The clinical score at inception and the presence of MEPs have the best
predictive potential.
