Development of a wearable system with In-Ear EEG electrodes for the monitoring of brain activities: An application to epilepsy

Epilepsy is a chronic noncommunicable disease of the brain characterized by recurrent seizures, which are brief episodes of excessive and synchronized electrical discharges of neuronal activities. The main technique used for the diagnosis of seizures is the electroencephalography (EEG), a noninvasive method which records the electrical activity of the brain. The conventional EEG monitoring to diagnose epilepsy has some problems: First, the short monitoring time generates misdiagnosis. Second, the long wires needed for the connection of electrodes are uncomfortable for the patients. Third, the patients are not monitored in a natural environment where different conditions can trigger seizures and last, a conventional EEG monitoring is too expensive. A solution is the development of a wearable monitoring EEG where the recording system is a device of small dimensions with continuous and long-term recording capabilities. In this work, we developed an In-Ear wearable system to allow a long-term recording of EEG signals in a nonclinical environment. For this, we designed In-ear electrodes with soft foam earplugs and a knit conductive fabric of silver. We performed different tests to validate the signal quality of the acquisition system including one ambulatory recording in an epileptic patient.