A computer program and device for determining a sleep state of an object animal. In the present invention, an fth indicator calculation unit (where f is an integer of 1 to F) compares [a curve Q representing a power spectrum of an object brain wave sub-segment Sb obtained from an object brain wave segment S] and [one or more curves Pf(m(f)) representing a power spectrum of a reference segment Rf(m(f))] to each other and calculates indicators df(m(f)) indicating degrees of similarity. On the basis of all the indicators df(m(f)), a sleep state determination unit evaluates whether brain waves of the object brain wave segment S are brain waves occurring during any of sleep states E1 through EF and thereby determines whether sleep in a period corresponding to the object brain wave segment S is in any of the sleep states E1 through EF. In a preferred embodiment, a sleep-wakefulness determination unit deletes a wakeful object brain wave segment S on the basis of a myoelectric signal prior to the above computations.
COMPUTER PROGRAM AND SLEEP STATE DETERMINATION DEVICE FOR DETERMINING SLEEP STATE OF OBJECT ANIMAL