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

Objective: This study investigated (1.) what type of changes in the motor cortex in stroke patients and to which degree such changes are associated with functional recovery and (2.) whether the type of motor training – rather than its intensity only – influences the success of any intervention in terms of adaptive motor cortex reorganisation and behavioural motor recovery after stroke.

Methods, results, and interpretation: In a sample of 28 subacute anterior circulation ischemic stroke patients in the subacute phase 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 documented in the affected hemisphere while motor cortex topology for the abductor pollicis brevis (APB) representation was comparable for the affected and non-affected hemisphere. When assessed four weeks later, the patient group showed considerable motor recovery (Fugl-Meyer test). Motor cortex excitability (motor thresholds, MEP amplitudes, number of active points) and conduction velocity in the corticospinal system improved in the affected hemisphere and APB representation showed a medial shift. The number of active points in the non-affected hemisphere had decreased at the same time. Multiple stepwise regression indicated that of all TMS parameter only the medial shift of the motor cortex map predicted motor recovery. Assessing the effect of intensity (conventional vs. intensified) and specificity of arm training (Bobath approach vs. Arm BASIS training) with a randomised controlled design revealed that intensity mattered less than specificity. Only the impairment-oriented Arm BASIS training induced motor recovery. This was associated with a medial shift of the motor cortex map and improved conduction times. It is therefore likely that the impairment-oriented training induced adaptive motor cortex reorganisation.

Supported by the BMBF (competence net stroke).