Sanyo Electric Co., Ltd.

Shima Okada

Yoshihisa Fujiwara

Yasushi Yamamoto

Takeshi Minamiura

Fumiiki Yoneda

Hidetaka Sakai

A sleep state of a subject is estimated from respiration signals that are readily detected without restraining the subject. From a voltage waveform based on respiratory movement of a person, positive peak values and the (time) interval between adjacent peaks are calculated. Also obtained is the area of a region that is enclosed by the voltage waveform and a time axis between peaks, and the average value and dispersion value of the obtained inter-peak areas are calculated. The calculated values are used to set a preliminary sleep state value for a given period, and sleep state values over plural periods are factored in to estimate a sleep state at a given time point.

Sleep state estimating device and program product

An object of the present invention is to provide a sleep state estimation device capable of estimating a sleep state (deep sleep, light sleep) in real time with relative simplicity. Voltage variations resulting from human respiratory movement are measured for each given period to calculate from the measurement results positive voltage peak values and time intervals between adjacent peaks. The obtained peak values and peak intervals are used to calculate a mean peak interval value A, a coefficient of variation B based on dispersion of the peak intervals, and a coefficient of variation C based on the peak values. The sleep state in this period is estimated from the calculation results. More specifically, referring to FIG., the sleep state is estimated as a 'wakeful state' or a 'hypnagogic state' by checking whether the mean value A is larger or smaller than a threshold a and whether the coefficient of variation C is larger or smaller than a threshold c (S) whereas the sleep state is estimated as the &#x201c;hypnagogic state&#x201d;, &#x201c;light sleep&#x201d; or &#x201c;deep sleep&#x201d; by checking whether the coefficient of variation B is larger or smaller than a threshold b and whether the coefficient of variation C is larger or smaller than the threshold c (S, S, S, S).

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Osaka, Japan

Shima Okada