Impairment–oriented training and adaptive motor cortex reorganisation after stroke: a fTMS study

Abstract

In a sample of 28 subacute anterior circulation ischemic stroke patients with severe arm paresis, reduced motor cortex excitability (increased motor thresholds, reduced MEP amplitudes, reduced number of active points) and a reduced conduction velocity in the corticospinal system were found in the affected hemisphere. At the same time motor cortex topology for the abductor pollicis brevis (APB) representation was comparable for the affected and non-affected hemisphere. Considerable arm motor recovery (Fugl-Meyer test) was observed when assessed four weeks later after a period of rehabilitation intervention. Motor cortex excitability and conduction velocity in the corticospinal system improved in the affected hemisphere. In addition, APB representation showed a medial shift in patients with such a representation at pre test (n=14). Multiple stepwise regression indicated that of all transcranial magnetic stimulation (TMS) parameters only the medial shift of the motor cortex map predicted motor recovery. Assessing the effect of training time (non-intensified vs. intensified therapy) and type of arm training (Bobath approach vs. Arm BASIS training) with a randomised controlled design revealed that the impairment-oriented Arm BASIS training improved motor control more than the control conditions. In addition, patients of the group receiving the Arm BASIS training with an APB representation at pre test showed a medial shift of the motor cortex map and improved conduction times. In conclusion, changes in motor cortex topology were likely to be relevant for motor recovery and might have been induced by the impairment-oriented training.