Electrocorticogram (ECoG): Engineering Approaches and Clinical Challenges for Translational Medicine

Electrocorticogram (ECoG) is an electrophysiological signal that results from the summation of neuronal activity near the cortical surface. To record ECoG signals, the scalp and skull are surgically opened and electrodes are placed on the cortical surface, either epidurally or subdurally. Owing to its improved spatiotemporal resolution and signal quality compared with electroencephalography, it is widely used to diagnose and treat neurological disorders in clinical settings for several decades, despite the invasiveness of ECoG. Recently, ECoG is applied in research to explore brain functions and connectivity, brain-computer interfaces, and brain-machine interfaces. In addition to the need for ECoG in neuroscience research, ECoG devices have advanced in terms of materials, fabrication, and function to overcome the limitations of commercially available ECoG arrays. Here, the conventional use of ECoG in clinical medicine, the new applications of ECoG in basic neuroscience research, and the future challenges in translating recent developments in ECoG devices for clinical use are described. This review summarizes the electrocorticogram (ECoG) and procedures currently used in clinical environments and recent technological developments toward emerging applications of ECoG beyond the current clinical use. The article discusses the limitations of currently used clinical ECoG and technological development toward micro-ECoG to overcome them, by tailoring mechanical properties closer to the brain tissue, improving spatial resolution, and integrating additional functions, which can foster new medical and neuroscientific applications of ECoG. image