Abstract
Motokawa's method for measuring fatigue takes as an index of fatigue a measure ΔS, which represents the difference between the threshold for appearance (S1) and that for disappearance (S2) of the flicker evoked by respective electrical stimulation of the eye. In the present investigation it was found that ΔS can be analyzed into two factors, the mean threshold (S) and the reaction time (T) for the minimum stimulus, where S is the arithmetical mean of S1 and S2. The relation can be expressed by the following formula,
ΔS=KS+2TV,
where K is constant and V the rate of raising and lowering the stimulating voltage. As indicated by this relation, two important factors S and T are embodied in a single measure ΔS which can be measured very easily by the Motokawa's method. Thus, our analysis has provided a theoretical ground for the usefulness of this method, and at the same time, a clue to the choice of experimental conditions such as illumination, the rate of raising and lowering the stimulating voltage, etc.
We wish to thank Prof. K. Motokawa for his good and cordial advice.
