Repetitive transcranial magnetic stimulation combined with treadmill training can modulate corticomotor inhibition and improve walking performance in people with Parkinson's disease.

Question: Does adding repetitive transcranial magnetic stimulation (rTMS) to treadmill training modulate cortical excitability and improve walking in people with Parkinson's disease (PD)?

Design: Randomised controlled trial with blinded outcome assessment.

Setting: A medical centre in Taiwan.

Participants: Individuals with Parkinson's disease (Hoehn and Yahr Stage 2-3), and ability to walk independently were key inclusion criteria. Absence of motor evoked potential in response to rTMS, history of seizure, and use of cardiac pacemaker were key exclusion criteria. Randomisation of 22 participants allocated 11 to each of the experimental and control groups.

Interventions: Both groups underwent 12 treatment sessions over 4 weeks. In each session, the experimental group received rTMS (5 Hz) applied over the leg area of the motor cortex in the hemisphere contralateral to the more affected leg for 6 minutes, immediately followed by 30 minutes of treadmill training. The control group received sham rTMS in addition to the 12 sessions of treadmill training.

Outcome Measures: The primary outcomes were indicators of corticomotor excitability - motor threshold, silent period, short-latency and long-latency intracortical inhibition - measured in both cerebral hemispheres. The secondary outcomes were comfortable and fast walking speeds, and the timed-up-and go test. The outcomes were measured at baseline and after the 4-week intervention period.

Results: 20 participants completed the study. At the end of the 4-week intervention period, the increase in motor threshold of 3.5% and silent period of 14.0% of the contralateral hemisphere relative to the more affected leg was significantly more in the experimental group than the control group. Significantly more reduction of short-latency intracortical inhibition in the same hemisphere was also found in the experimental group relative to the control group 10.9%. The experimental group also had significantly more improvement than the control group in fast walking speed (by 10.1cm/s) and in the timed up- and-go test (by 2.0 s). No significant differences between the groups were reported in other outcomes.

Conclusion: Repetitive transcranial magnetic stimulation can enhance the effects on corticomotor inhibition and improvement of walking function induced by treadmill training in patients with Parkinson's disease.