High-density EEG. Overview and scope of application

In 2024, electroencephalography (EEG) technique turned 100 years old. Despite its seemingly advanced age, electroencephalography remains one of the main instrumental methods for diagnosing brain functional state. EEG is widely used in modern clinical practice as well as in numerous research studies. At the same time, this method continues to improve, with increasing number of recording channels being one of the upgrade trajectories. If 19–25 EEG channels are recorded traditionally for routine EEG examinations, 32 channels are used in advanced laboratories, whereas 64- and even 128-channel systems are often applied for scientific research. As a rule, multi-channel recorders are used for invasive EEG. For scalp EEG, the logical limit for the number of applied electrodes has become 64 channels, although in exotic cases as many as 256 scalp EEG channels may exist. Such multi-channel EEG recording is called “high-density EEG”. Here, some practical aspects of using multi-channel EEG as well as its new diagnostic capabilities are discussed.