Repetitive transcranial magnetic stimulation (rTMS) can facilitate a reorganisation of functional areas in the brain as well as support the recruitment of new areas. We use this mechanism in the treatment of patients with brain tumors, to reduce the risk of motor deficits after a surgery or to treat existing deficits. M.Sc. Melina Engelhardt and her team are investigating different neuromodulatory approaches as adjuvant treatment of motor impairments.
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rTMS in healthy subjects
The effects of rTMS on motor outcomes have been investigated in various studies. A standardisation of the applied protocols is, however, mostly missing. Studies to determine the optimal treatment duration, frequency or location are needed to increase the effect of the stimulation. For this study, healthy subjects received five days of rTMS, with motor outcomes being measured every day before and after the intervention. The goal of the study was the optimisation of the stimulation duration.
Effects of low-frequency rTMS on excitability of the motor cortex
RTMS has been shown to have positive effects on motor rehabilitation of stroke patients, however there is a lack of standardization in the applied stimulation protocols as well as a missing insight in underlying mechanisms. This study investigated excitability of both hemispheres across several stimulation days in order to optimize the parameters of the intervention.
Treatment of a postoperative paresis after brain tumor surgery with TMS
It is known that a hemiparesis after ischemic stroke is not only caused by damaged neurons in the lesional hemisphere but also by an unbalanced interhemispheric excitability. In detail, the regular callosal inhibition of the healthy hemisphere by the lesional is missing. Consecutively, the healthy hemisphere is more active which results in an “over-inhibition” of the lesional hemisphere (Perez et al. 2009). The principle of the rTMS treatment is to compensate this unbalanced interhemispheric excitability by inhibiting the “over-active” healthy hemisphere. In stroke studies, patients treated with rTMS had a better and faster recovery. We investigate this treatment concept as adjuvant treatment in patients after a brain tumor surgery.
TMS mapping of the supplementary motor area
The supplementary motor areas of the cerebral cortex are significantly involved in the planning and execution of movements and speech. Accordingly, damage to these areas can lead to significant motor or speech impairments. In the context of this study, we established a protocol for preoperative mapping of supplementary motor areas near the tumor. In this way, areas that are central to the execution of movements or speech can be precisely localized and this information can be considered for operation planning.