It is known that response personnel deployed in disaster areas are subjected to excessive stress, which can lead to mental disorders such as post-traumatic stress disorder and depression (Raphael et al. 1984; Fullerton et al. 2004; Perrin et al. 2007; Dobashi et al. 2014). A high frequency of mental health assessment is necessary to protect them from mental illness. Various methods have been proposed to assess mental status, but these methods must be noninvasive and low-cost, taking into account the burden on the subject to be assessed if they are to be conducted at high frequencies.