Final answer:
Brachial plexopathy and diabetic polyneuropathy can affect sensations like proprioception, pain, temperature, and light touch, with proprioception being one of the primary senses impacted.
Step-by-step explanation:
Brachial plexopathy and diabetic polyneuropathy affect multiple types of sensations including proprioception, pain, temperature, and light touch. To specifically address the question, these conditions affect the sensory modality of proprioception, which is the sense of the relative position of one's own parts of the body and strength of effort being employed in movement. Diabetic polyneuropathy typically affects all modalities due to the generalized damage to peripheral nerves, including sensations such as temperature, pain, and light touch. Meanwhile, brachial plexopathy can affect the brachial plexus which includes nerves that mediate these sensations in the upper limbs. Sensory tests for proprioception may involve assessing the ability to perceive the movement of fingers or toes. These tests can identify nerve damage or dysfunction which may be suggestive of conditions like brachial plexopathy or diabetic polyneuropathy.