In our aging society, the number of people suffering from cerebrovascular or degenerative brain diseases, such as stroke and Alzheimer's disease, is rapidly increasing. It is imperative for those suffering from such slow progressing and recurring brain diseases to continuously monitor and manage their brain conditions. Currently available brain-monitoring techniques, such as computed tomography (CT) and magnetic resonance imaging (MRI) are expensive and cumbersome for such a purpose, resulting in the need to develop a brain monitoring system in the form of a wearable healthcare device.