Controlled trial on the effect of 10 days low-frequency repetitive transcranial magnetic stimulation (rTMS) on motor signs in Parkinson´s disease

Abstract

[Abstract] We evaluated the effect of low-frequency rTMS on motor signs in Parkinson’s disease (PD), under a doubleblind placebo-controlled trial design. PD patients were randomly assigned to received either real (n 5 9) or sham (n 5 9) rTMS for 10 days. Each session comprises two trains of 50 stimuli each delivered at 1 Hz and at 90% of daily rest motor threshold using a large circular coil over the vertex. The effect of the stimulation, delivered during the ON-period, was evaluated during both ON and OFF periods. Tests were carried out before and after the stimulation period, and again 1 week after. The effect of the stimulation was evaluated through several gait variables (cadence, step amplitude, velocity, the CVstride-time, and the turn time), hand dexterity, and also the total and motor sections of the UPDRS. Only the total and motor section of the UPDRS and the turn time during gait were affected by the stimulation, the effect appearing during either ON or OFF evaluation, and most importantly, equally displayed in both real and sham group. The rest of the variables were not influenced. We conclude the protocol of stimulation used, different from most protocols that apply larger amount of stimuli, but very similar to some previously reported to have excellent results, has no therapeutic value and should be abandoned. This contrasts with the positive reported effects using higher frequency and focal coils. Our work also reinforces the need for sham stimulation when evaluating the therapeutic effect of rTMS.