Evaluation of three types of blinks with the use of electro-oculogram and electromyogram.

Three kinds of blinks, spontaneous, reflex, and voluntary, were measured for 11 men using electromyogram (EMG) at the orbicularis oculi muscle on the right side and electro-oculogram (EOG) in the vertical direction to the right eyelid. The amplitude and the duration time were defined here from the raw waves of the EMG and the EOG for the three kinds of blinks. The amplitude of the EMG indicated that the mean value for the spontaneous blinks was significantly smaller than that of the voluntary blinks and the mean duration of the EMG shows the value for the spontaneous blinks was smaller than that for the reflex and the voluntary blinks. The EMG for the spontaneous blinks had a smaller amplitude and a shorter duration time than the other blinks. The EOG amplitude indicated that the mean value for the spontaneous blinks was significantly smaller than that for the voluntary blinks, but there was no significant difference between the spontaneous blinks and the other blinks for the duration of the EOG. The amplitude and the duration for both the EMG and the EOG discriminated any two types of blinks from three blinks by statistical test. Those values for the EMG and the EOG are effective indices for the evaluation of blinks. Moreover, the coefficients of variation of the amplitude and durations of EMG and EOG for three kinds of blinks denote their characteristics. Multiple discriminant analysis distinguished the types of blinks simultaneously. The resultant maximum correct rate for the three blinks reaches to be 81.8%. So far, it has been difficult to discriminate the blinks quantitatively, but the procedures presented here are able to solve the difficulty.