Effects of Combined rTMS and Treadmill Training in People With Parkinson's Disease

Each participant is instructed to walk for 14 meters at their fastest walking speed for three trials. The time taken for the middle 10 meter was recorded. The average of three trials is used for analysis.

Participants are instructed to stand up from a chair and walk for 7 meters walkway and return back to the chair turn around and sit down.

Time and gait parameters during TUG were captured by the valid and reliable APDM system, which is a wearable gait and balance analysis system.

MDS-UPDRS III is a valid and reliable clinical test, will be used to evaluate severity of motor symptoms of PD. There are total of 27 items including tremor, rigidity, bradykinesia, postural instability and gait performance. Each item scores from 0-4, with 0 indicates no disability and 4 maximum disabled with total score(s) ranges from 0 to 132.

The 2 minute walk test will be conducted along a 20 m x 2 m hallway. A line is marked at each end of the walkway to indicate where the person is to turn. Participants will be instructed to " walk as far as possible in 2 minutes". They will be given standardised encouragement at 60 and 90 seconds during walk. Distance walked will be recorded to the nearest meter.

Balance performance of participants will be assessed in 4 domains namely anticipatory postural adjustments, postural responses, sensory orientation and gait stability. Each item is rated from 0-2 with a total scores of 28. The Total scores range from 0-28, with higher scores indicate better dynamic balance.

For DT-TUG, participants were instructured to repeat the TUG procedure while performing a serial three substraction. Time taken to complete DT-TUG and accuracy of digital counting was recorded. One practice trial was given prior to both TUG and DT-TUG testing and average performance of three trials was used for analysis.

Ten suprathreshold TMS stimuli (i.e. 130% RMT) will be delivered while participant performing a 20% isometric maximal contraction of Tibialis Anterior of the more affected side. Cortical silent period (CSP) measures the duration of interruption of electromyography (EMG) activity in the contracting muscle produced by TMS. CSP duration will be determined as the period between the onset of MEP and the return of baseline EMG activity measured 50 ms before the TMS stimulus.

TMS stimuli will be applied at 10% steps between 100% to 160% RMT. 10 stimuli will be delivered at each intensity. Peak to peak amplitude of 10 motor-evoked potentials (MEPs) at each stimulus intensity will be averaged offline.The cut-off intensity is set at 75% of maximum stimulator output due to discomfort perceived by majority of the participants. MEPs will be normalised with the maximal muscle action potential (MMax), which is determined by supramaximal electrical stimulation of the fibular nerve. A scatter graph will be generated with the average amplitude of MEPs as a function of stimulation intensity. The linear trend will be added to generate the linear recruitment curve slope.

Short-interval-intracortical inhibition (SICI) is another measure of cortical inhibition. In a paired- pulse TMS paradigm, a test pulse will be adjusted to produce MEP of at least 0.5 millivolts which will be delivered preceded by a brief conditioned pulse set at a lower intensity of 80% RMT with inter-stimulus interval of 2 milliseconds. Two stimulators connected via a Bistim module ( Magstim Co.,Whitland, UK) will be used in this test. Ten conditioned MEPs and unconditioned MEPs will be obtained in a random order and were averaged for each condition. SICI is expressed as percentage of unconditioned test MEP amplitude.