Are the Effects of rTMS in Parkinson's Disease Clinically Relevant?

Abstract

Introduction. Earlier studies have shown that brain stimulation by means of repetitive Transcranial Magnetic Stimulation (rTMS) over the primary motor cortex can decrease the motor impairments in Parkinson’s disease (PD). The present study focused on the clinical relevance of rTMS in the treatment of PD. Method. Thirteen PD patients received a minimum of 10 sessions of 2,000 pulses 5 Hz rTMS over the hand and leg area over the primary motor cortex, with a stimulation intensity of 120% of the motor threshold. In our analysis an effect could be considered as clinically relevant if the quality of life (QoL) improved with 30% or more. Results. Paired-sample t-tests revealed a significant improvement of Unified Parkinson’s Disease Rating Scale score, walking speed, and mood. A minority of the patients (38%) who underwent rTMS showed an improvement in QoL of greater than 30%. The improvements in QoL correlated significantly to scores of motor improvements on the Unified Parkinson’s Disease Rating Scale but not to improvements in mood as assessed by the Geriatric Depression Scale. The use of rTMS did not demonstrate any effects on tremor, freezing of gait, and activities of daily life, and rTMS had no effect on the stage of disease. It mainly improved rigidity, finger and hand movements, and leg agility. Conclusion. This study shows that although there can be significant group effects of rTMS on PD symptoms, these significant effects do not automatically imply that these are clinically relevant. Therefore we advise that future studies in the field of neuromodulation (rTMS, neurofeedback, etc.) also focus more on the clinical relevance of the treatment under investigation rather than only report ‘‘significant group differences.’’