The following is a collection of research abstracts pertaining to the application of rTMS and other electromagnetic stimulation techniques for the relief of Parkinson's disease symptoms. There is also additional supporting evidence for the proposed potential of electromagnetic therapy application for relieving the symptoms of Parkinson's disease as well as support for the associated theory of mechanism of operation driving the change.
The diagnostic and therapeutic application of transcranial magnetic stimulation
Neurol Neurochir Pol.2005 Sep-Oct;39(5):389-96.
Derejko M, Niewiadomska M, Rakowicz M.
Zaklad Neurofizjologii Klinicznej, Instytut Psychiatrii i Neurologii, ul. Sobieskiego 9, 02-957 Warszawa.
The functional abnormalities of the central motor structures and its contribution of rigidity, tremor and bradykinesia in Parkinson's disease seem mainly due to the degeneration of the nigro-striatal pathway. Transcranial magnetic stimulation (TMS) of the motor cortex may provide useful data on the pathophysiology of motor dysfunction in Parkinson's disease. Recent reviews on the basic mechanisms of TMS in Parkinson's disease show reduced inhibitory motor network at the cortical and spinal level. The observed changes are thought to be in relation with a dysfunction of subcortico-cortical and subcortico-spinal pathways. The abnormalities of the central motor function seem to be modified by several clinical related factors as prevalence of cardinal Parkinson's disease signs (e.g. rigidity versus tremor or bradykinesia), L-dopa therapy ('on/off' states) and laterality of the Parkinson's disease signs. Observations made using TMS give new pathophysiological insights in functioning of the central motor structures in Parkinson's disease and started new form of TMS - repetitive TMS (rTMS) as a treatment of the Parkinson's disease motor signs. A few studies using rTMS with repetition rate of 0.2, 1, and 5 Hz showed improvement of motor signs in the Parkinson's disease patients.
Motor cortex dysfunction revealed by cortical excitability studies in Parkinson's disease: influence of antiparkinsonian treatment and cortical stimulation.
Clin Neurophysiol. 2005 Feb;116(2):244-53. Epub 2004 Dec 24.
Lefaucheur JP.
Service de Physiologie--Explorations Fonctionnelles, Hopital Henri Mondor, Assistance Publique--Hopitaux de Paris, 51 avenue de Lattre de Tassigny, 94010 Creteil, France.
Single or paired pulse paradigms of transcranial magnetic stimulation (TMS) provide several parameters to test motor cortex excitability, such as motor threshold (MT), motor evoked potential (MEP) amplitude, electromyographic silent period to cortical stimulation (CSP) and intracortical facilitation (ICF) or inhibition (ICI). Various changes in TMS parameters, revealing motor cortex dysfunction, were found in patients with Parkinson's disease (PD). For instance, low MT and increased MEP size disclosed an enhanced corticospinal motor output at rest, while reduced ICF and failure of MEP size increase during contraction suggested defective facilitatory cortical inputs, particularly for movement execution. Inhibitory cortical pathways were also found less excitable at rest (reduced ICI) and sometimes during contraction (shortened CSP). By restoring cortical inhibition, dopaminergic drugs and deep brain stimulation probably overcome the difficulty to focus neuronal activity onto the appropriate network required for a specific motor task. The application of repetitive TMS trains over motor cortical areas also showed some effect on cortical excitability, opening perspectives to consider the motor cortex as a target for therapeutic neuromodulation in Parkinson's disease.
Long-term follow-up study with repetitive transcranial magnetic stimulation (rTMS) in Parkinson's disease.
Brain Res Bull. 2004 Sep 30;64(3):259-63.
Mally J, Farkas R, Tothfalusi L, Stone TW.
NeuroRehabilitation, Lover krt. 74, Sopron H-9400, Hungary.
Several studies have claimed the effectiveness of repetitive transcranial magnetic stimulation (rTMS) in Parkinson's disease (PD). Two different groups of patients with PD were compared in a retrospective study for 3 years. The first group (A) was treated with drugs; the second group (B) was treated with drugs + rTMS (1 Hz, 0.6 T, 100 stimuli per day for 7 days using a round coil). rTMS was repeated at least twice each year for 3 years. Symptoms of PD were assessed using the Graded Rating Scale. Although at the onset of the study group B patients had greater disease severity and were receiving higher doses of levodopa, this group (receiving rTMS) showed no deterioration in these parameters, whereas those in group A receiving drugs alone showed a marked deterioration. Hoehn-Yahr (H-Y) stages at the onset of the study and 3 years later were: group A: 1.93 +/- 0.75, 3.03 +/- 1.01; group B: 2.50 +/- 0.83, 2.45 +/- 0.62. The dose of levodopa (mg/day) was at the onset of trial and 3 years later was: group A: 124.4 +/- 144.0, 555.5 +/- 247.2; group B: 287.7 +/- 217.1, 333.4 +/- 181.0. The yearly increment in the scores was: group A: 1.308 +/- 0.307 (P < 0.001), group B: 0.642 +/- 0.389 (P < 0.1). Accordingly, this retrospective study using regularly repeated rTMS with 1 Hz for 7 days, at least twice yearly for 3 years, significantly slowed the development of Parkinson's disease. Unwanted side effects were not observed during the 3 years.
