Development of an Input Interface Using Ocular Potential for Handicapped Users of Health Care Supporting Computer

Numerous attempts to adapt multimedia communication to medical care have been reported recently. It is our view that spiritual support is more important in medical care, while so-called high technology may be necessary for medical practice. Therefore, we proposed the concept of the Hyper Hospital [1–3], to offer patients a means of effective human communication during medical care. The Hyper Hospital is a medical system constructed on a computer and multimedia based-network, which patients use to participate in medical and care activities through improved communication media. It is sometimes difficult for physically handicapped patients, such as PMD (progressive muscular dystrophy), ALS (amyotrophic lateral sclerosis), and traumatic cervical injury patients, to operate a computer, because of their disabilities. Therefore, there is a serious digital divide between physically disabled patients and healthy people. To remedy this, various communication devices, such as those using winking, eye gaze, voice, and electrical biological signals (event-related potential [4–5], electrooculogram, etc.) have been proposed and tested. These are designed to enable seriously handicapped patients to use a computer without using the usual mechanical input devices, such as a keyboard, mouse, or joystick. Although an EEG (electroencephalogram) offers one source of such potential electrical biological signals, it produces a very weak electrical signal that contaminating noise makes difficult to process. On the other hand, the ocular potential generated by the dipolar potential of the eyeball has a much larger gain in potential than the EEG. Moreover, the ocular potential can be easily controlled by the user, and eye-movement ability remains largely intact, even after neurological diseases progress to a very advanced stage. Therefore, this report studied the development of an input interface for computers using an electrooculogram.