Electroencephalography (EEG) is a non-invasive technique used to measure the electrical activity of the brain. The use of EEG is very important for the diagnosis of traumatic brain events and mental states such as injury, stroke, depression and many others including the COVID-19 brain fog syndrome. The quality of EEG signals largely depends on the nature of the interface between the surface of the electrode material and the surface of the scalp from where the electrical brain signals are acquired. The scalp surface is composed of an epidermic substrate with hair, grease, dirt, dandruff, skin peels and eventually many different hair products. The electrodes must combine several properties including electrical conductivity, mechanical strength, biocompatibility and corrosion resistance. They also must be manufactured with shapes designed to overcome the inherently complex nature of the scalp–electrode interface. This review reports the latest advances in the design of materials, surface coatings, conductive gels and information and communication technologies being developed to increase the quality of measurement of brain electrical signals in EEG protocols.

脑电图（EEG）是一种用于测量大脑电活动的非侵入性技术。脑电图的使用对于诊断创伤性脑事件和精神状态非常重要，例如受伤、中风、抑郁和许多其他疾病，包括 COVID-19 脑雾综合症。脑电图信号的质量很大程度上取决于电极材料表面和获取脑电信号的头皮表面之间的界面的性质。头皮表面由表皮基质组成，其中有头发、油脂、污垢、头皮屑、皮肤脱落以及最终的许多不同的护发产品。电极必须结合多种特性，包括导电性、机械强度、生物相容性和耐腐蚀性。它们的制造形状还必须能够克服头皮-电极界面固有的复杂性。这篇综述报告了材料、表面涂层、导电凝胶以及信息和通信技术设计的最新进展，这些技术旨在提高脑电图协议中脑电信号的测量质量。