ABSTRACT

Continuous, long-term scalp electroenchephalogram (EEG) monitoring of brain activity is difficult to perform on awake, ambulatory patients because of increased artifacts from muscles and electronic interference, as well as frequent electrode replacement over time. Prior research has shown that subdermal wire electrodes placed below the scalp maintain good recording characteristics with stable impedances for long-term monitoring of EEG signals. This chapter provides evidence that an implanted subdermal recording electrode system may provide a reliable, long-term, portable method for recording motor-related signals from the brain. This chapter outlines a study that found that neural recordings that used subdermal electrodes were comparable to those of scalp surface recordings, particularly in the low-frequency bands (8–30 Hz). The coherence results indicate that there appears to be mutual information between the subdermal and surface electrode signals in the low-frequency signal, but many of signals in the higher frequencies (>40 Hz) may be unique to each surface and subdermal electrode. These results further support the idea that an implantable subdermal electrode system may provide reliable, long-term motor control signals for brain–computer interface control.