Brain activity has traditionally been assessed using large and often expensive technology that has limited its use to specific clinical settings. Small wearable devices that can assess brain activity are hoped to improve the diagnosis and monitoring of brain diseases like dementia or depression. In a study published recently in Advanced Materials Technologies, researchers from Osaka University have developed a wearable device that is unobtrusive and comfortable, which can measure brain activity in everyday situations—and its technology may potentially monitor many other health indicators as well.

Unlike other health-related measurements that can be taken at home, such as blood pressure or weight, brain activity currently needs to be evaluated by highly trained medical staff using bulky and expensive equipment. Thus, scans tend to be infrequent, and changes are often not immediately noted or treated. To combat these problems, the development of small wearable devices using electroencephalography—where electrodes measure electrical activity on the scalp as an estimate of the underlying brain activity—has recently begun. However, such devices are usually painful when worn long-term and often have low signal-to-noise ratios, which limits their sensitivity. The research team at Osaka University thought that they might be able to do better.

“We were able to fuse together organic and inorganic materials to create a stretchable and transparent sensor sheet that can be worn on the forehead, is gentle to the skin, and is invisible to the eye,” says lead author of the study Teppei Araki. “Unlike conventional wearable devices, our multifunctional electrode system has medical device-like performance, is easy to apply, and is comfortable to wear for long periods of time.”