Using a small sensor and a smartphone, people suffering from epilepsy can now detect when they are about to have a seizure. The system, developed by a team at Kyoto University, provides warnings of 30 seconds or more, helping patients to avoid injury from falls or other accidents.
The team, led by assistant professor Koichi Fujiwara, is working with Kumamoto University and Tokyo Medical and Dental University to ready the system for practical use by 2020.
Epileptic seizures are caused by sudden excessive electrical discharges in a group of brain cells. They can range from a brief lapse of consciousness and uncontrolled muscle contractions to severe and prolonged convulsions. Around 50 million people worldwide have epilepsy, according to the World Health Organization, and it affects people of all ages.
The team conducted studies on focal seizures, which affect only part of the brain, and paid special attention to patients' heartbeats. Immediately prior to a seizure, changes in nerve cell activity affect the autonomic nerves that control the heart.
The system the team developed to detect these changes uses a sensor, worn near the collarbone or the heart, and a smartphone, which receives the sensor's signals wirelessly and uses a special app to analyze them. The cost, excluding the handset, is below 10,000 yen ($85), the team said.
To determine whether a patient's heartbeat is behaving abnormally, the system must first create a baseline profile by taking measurements under normal conditions. When the heartbeat deviates from that baseline, the system alerts the wearer with a sound or vibration. According to the team, about 10 seconds would be enough time for a patient to take precautions and avoid being injured during a seizure.
In tests conducted with patients from Tokyo Medical and Dental University, abnormal heartbeats were detected anywhere from 30 seconds to several minutes prior to seizures in five out of six patients. Last year, the team started clinical tests involving 60 patients from the National Center of Neurology and Psychiatry.
So far, the system has been tested only on patients at rest. The team hopes to increase the system's accuracy so that it can detect imminent seizures when patients are walking or otherwise on the move.
Other research into advance detection of seizures has included monitoring brain waves, but such methods have not been successful.