Within ACL 1, the person's attention is aroused by strong sensory cues that stimulate any of the five senses, one at a time. The person experiences, evaluates and responds to their sensations.
Moving in bed or in a fully supported seating, without head control is the limit of their physical, gross motor control.
The person's use of language is limited to producing sounds but not words. They understand simple instructions made with universal gestures, such as pointing as well as one to three-word commands. They are not particularly hard of hearing and shouting at them is unnecessary. When shouting scares them, startle reactions occur.