Safety Study of Combination Treatment: Deep Brain Stimulation and Transcranial Magnetic Stimulation

Area of Science:

• Biomedical Engineering
• Neuroscience
• Medical Physics

Background:

• Advanced Parkinson's disease (PD) patients often undergo deep brain stimulation (DBS) for motor symptoms.
• DBS does not fully address speech and swallowing impairments, for which transcranial magnetic stimulation (TMS) shows potential.
• The safety of combining DBS with TMS, particularly electromagnetic interactions, is not well understood.

Purpose of the Study:

• To investigate the safety of combining deep brain stimulation (DBS) and transcranial magnetic stimulation (TMS).
• To quantify the induced currents on DBS leads during TMS application in a realistic phantom model.

Main Methods:

• Anatomically accurate head and brain phantom created with relevant tissue conductivities.
• Measurement of induced current on a simulated DBS lead within the phantom.
• Simulation of TMS application over the DBS lead.

Main Results:

• Transcranial magnetic stimulation (TMS) induces currents in deep brain stimulation (DBS) leads.
• Induced current values can reach or exceed typical DBS stimulation levels.
• Direct stimulation over the DBS lead with 100% TMS intensity may cause over-stimulation.

Conclusions:

• The combination of TMS and DBS presents potential safety risks due to induced currents.
• Further research is needed to establish safe parameters for concurrent TMS/DBS therapy.
• Careful consideration of electromagnetic interactions is crucial for developing combined neuromodulation strategies.