Final answer:
The patient reaching into a paper bag to feel an object assesses tactile sensation, specifically stereognosis, as part of the gnosis subtest in sensory perception. Proprioceptive sensation, which is different, can also be tested by asking patients about sensing finger or toe movements without visual cues.
Step-by-step explanation:
The activity described where a patient reaches into a paper bag and feels the ball without being able to see it, is directed at assessing the patient's tactile sensation or somatosensory function, specifically stereognosis. This is part of the sensory perception subtest known as gnosis, which involves identifying objects through somatosensory information that comes from manipulating them. Moreover, assessing different sensory modalities such as tactile movement or proprioceptive sensation is crucial in determining the integrity of a patient's peripheral and central nervous pathways.
For evaluating proprioceptive sensation, tests such as assessing the sense of position and motion of the fingers or toes are performed. The patient is asked if they sense the movement, which is a component of proprioception; this is different from stereognosis which focuses on the ability to recognize objects by touch. Sensory tests like two-point discrimination, perception of tactile movement, and recognizing numbers or letters written on the palm of the hand (graphesthesia) are essential in diagnosing and understanding sensory deficits.