Recovery of upper-limb function due to enhanced use-dependent plasticity in chronic stroke patients

Abstract

Patients with chronic stroke often show increased flexor hypertonia in their affected upper limbs. Although an intervention strategy targeting the extensors of the affected upper limb might thus be expected to have benefits for functional recovery, conventional repetitive motor training has limited clinical utility. Recent studies have shown that repetitive transcranial magnetic stimulation could induce motor recovery. The present study tested whether 5 Hz repetitive transcranial magnetic stimulation of the upper-limb area of the primary motor cortex, combined with extensor motor training, had a greater effect on motor recovery than either intervention alone in stroke hemiparesis. Nine patients with chronic subcortical stroke and nine age-matched healthy subjects completed the crossover study. In separate sessions, we examined the single intervention effect of repetitive wrist and finger extension exercises aided by neuromuscular stimulation, the single intervention effect of 5 Hz repetitive transcranial magnetic stimulation and the combined effect of the two interventions. The motor functions were evaluated behaviourally in patients (Experiment 1) and electrophysiologically in healthy subjects (Experiment 2), both before and after the intervention. In addition, we tested the long-term effect by repeating the combined interventions 12 times in patients (Experiment 3). The motor functions were measured again 2 weeks after the end of the repetitive intervention period. In Experiment 1, the combined intervention, but neither of the single interventions, resulted in an improvement of extensor movement (P < 0.0001) and grip power (P < 0.05), along with a reduction of flexor hypertonia (P < 0.01), in their paretic upper limbs. In Experiment 2, only the combined intervention resulted in selective plastic changes of cortico-spinal excitability (P < 0.01), motor threshold (P < 0.001) and silent period (P < 0.01) for the extensors. In Experiment 3, we also confirmed long-term beneficial effects of the combined intervention in patients. These findings indicate that combining motor training with repetitive transcranial magnetic stimulation can facilitate use-dependent plasticity and achieve functional recovery of motor impairments that cannot be attained by either intervention alone. This method could be a powerful rehabilitative approach for patients with hemiparetic stroke.

Human Motor Plasticity Induced by Mirror Visual Feedback

“…We hypothesized that motor training of the hand would produce a plastic change in motor behavior and M1 function of the contralateral hand when MVF was applied to the subject. Using TMS allowed us to study the excitatory and inhibitory functions of the human M1 extensively and noninvasively (Pascual-Leone et al, 1998;Koganemaru et al, 2009Koganemaru et al, , 2010Thabit et al, 2010). In addition, we tested whether continuous theta burst stimulation (cTBS) over the M1 (Huang and Rothwell, 2004;Huang et al, 2005) can disrupt the behavioral and electrophysiological motor improvement induced by MVF.…”

Efficacy of Synchronous Verbal Training During Repetitive Transcranial Magnetic Stimulation in Patients With Chronic Aphasia

“…Motor training incorporated concurrently into an excitatory rTMS session was found to facilitate motor recovery that could not be obtained by either remedy alone after a single intervention. 9 Using a direct transcranial electric current, simultaneous physiotherapy was executed during the conditioning course and demonstrated a favorable outcome, compared with sham stimulation combined with physiotherapy. 10 On the basis of this model, which pertains to a motor training program, online speech therapy during rTMS modulation should augment language learning.…”

Physical Therapy for Cerebellar Ataxia

“…NIBS, which is repetitive TMS (rTMS) [96,98] and transcranial direct current stimulation (tDCS) [124], over the primary motor cortex can modulate the excitability of the motor cortex [125] and is often used as an effective tool for enhancing behavioral training after stroke with hemiplegia [125][126][127][128]. Furthermore, the NIBS to the cerebellum modulates cerebellar excitability [98,[129][130][131], motor function [132,133], and motor learning [32,[134][135][136][137][138] in healthy population.…”