A verbal and / or tactile cue to lift and hold captures attention, which can be sustained with constant cuing.
Noticing the effects of gravity requires paying attention to internal cues about the entire length of the body within ACL 1.6. Within ACL 1.8, the body part is identified, located, lifted, held still for a few minutes, and returned to a prior position. The action can be experienced, compared with prior actions, evaluated and choices can be made about cooperating with carers. Holding a position against gravity requires sustained attention to maintain the necessary muscle strength. Constant cuing refers to the need to remind them every few seconds. The number of cues per minute can be measured.
Automatic shifts in trunk position in response to the effects of gravity are the reason that the person can sit up longer in ACL 1.8 than in ACL 1.6. Sitting up longer is linked to being more responsive and selective about sensory cues and variations in sustained attention.
People with the necessary muscle strength may not have the mental power to sustain attention, which is a common observation with young men who have traumatic brain injuries. Elderly people with progressive decline in ability to function also lack the mental power to sustain attention. A gradual decline in physical and mental abilities makes it difficult to separate the two when they decrease together.