Research of the Switch Operation by Voluntary Blinks Utilizing EOG

Abstract

This paper describes the development of the intention transmission support system, which uses the eye blink that deals with the amyotrophic lateral sclerosis (ALS) patient. ALS attacks the motor neurons, nerve cells in the brain and spinal cord that control the body's voluntary muscles. As the disease progresses, ALS patients gradually lose the use of their arms, legs, and neck muscles, ultimately becoming paralyzed. Because of that as for the ALS patient intention transmission becomes very difficult. Furthermore, many ALS patients are usually maintaining control of a motion of blink. The ALS patients can therefore use blink for communication. Eye blinks can be classified into voluntary blink and spontaneous blink. If the spontaneous blink is considered as operation of a switch, there are many incorrect inputs. Because the spontaneous blink things happen unconsciously. Therefore, the spontaneous blink is not suitable as operation of a switch. On the other hand, a voluntary blink can be used as operation of a switch. The EOG amplitude indicated that the value for the spontaneous blinks was significant difference between the spontaneous blinks and the other blinks for the duration of the EOG. In addition, the blink waveform is different from the eye movement EOG waveform. It is possible to extract a blink from an EOG waveform by the amount of change of the corneoretinal potential. Experimental measurements were performed in order to extract the voluntary blink from EOG waveforms. Two kinds of blinks, spontaneous, voluntary, and eye movement were measured for 8 men using EOG in the vertical direction to the right eyelid. As a result, all subjects were extraction rates more than 94%. We evaluate the usefulness of communication tool using voluntary blink. Therefore, we experimented on the character input. As a result, all subjects were success rates more than 88.5%. From what has been discussed above, we can conclude that voluntary blink can be used as operation of a switch.