A method for detecting occupant position change on a support surface includes establishing a rate of change of pressure in a head end test zone and in a foot end test zone, comparing the head end rate to at least one head end rate limit, comparing the foot end rate to at least one foot end rate limit, and inferring, in response to the comparing steps, whether or not occupant migration has occurred. An associated occupant support includes a frame and a mattress. The mattress includes head and foot zones each having at least one pressurizable bladder. The support also includes a controller adapted to compare a head end pressure change to a head end change limit, to compare a foot end pressure change to a foot end change limit, and to infer, in response to the comparing steps, whether or not occupant migration has occurred.
