Thermal Analysis of a Skull Implant in Brain-Computer Interfaces

Area of Science:

• Biomedical Engineering
• Neuroscience
• Computational Modeling

Background:

• Developing implantable brain-computer interfaces (BCIs) requires careful consideration of device thermal impact.
• Electrocorticogram (ECoG)-based BCIs offer high-resolution neural signal recording and stimulation.
• A fully implantable BCI necessitates a robust and safe external housing, such as a titanium skull unit (SU).

Purpose of the Study:

• To estimate the thermal impact of a titanium skull unit (SU) designed for an electrocorticogram (ECoG)-based bi-directional (BD) brain-computer interface (BCI).
• To determine the maximum power consumption allowable for the SU without exceeding safe temperature limits in surrounding human skull tissues.
• To validate the SU design's suitability for housing BCI components and supporting neural recording and stimulation functions.

Main Methods:

• Utilized the bio-heat transfer equation with physiologically and anatomically constrained tissue parameters.
• Employed the finite element method (FEM) for computational modeling.
• Simulated the thermal effects of the titanium skull unit using COMSOL software.

Main Results:

• Predicted that the SU can safely consume up to 75 mW of power.
• Determined that this power level does not elevate surrounding tissue temperature beyond the 1°C safe limit.
• The calculated power budget significantly exceeds the requirements of current front-end BCI prototypes.

Conclusions:

• The titanium skull unit design is thermally safe for housing implantable BCI components.
• The SU's thermal performance supports its use for both ECoG signal recording and cortical stimulation.
• Simulation results provide crucial data for refining current SU designs and informing future BCI hardware development.