“…In addition to its potential applications in mobile health, in-ear signal capture has also gained interest for human–machine interface (HMI) applications [ 2 ]. In-ear dry electrodes can capture various physiological signals, such as electrocardiography (ECG), electrooculography (EOG), electromyography (EMG), and electroencephalography (EEG) [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ], which can be used, for example, for sleep stage analysis and to detect and classify cognitive and emotional states. This has the potential to enhance the interaction between humans and machines in various fields, including gaming, virtual reality, and neuroprosthetics [ 11 ].…”