Which modalities are used to assess dorsal column function?

• A. Vibration and position sense
• B. Temperature and pain
• C. Light touch and pressure
• D. Proprioception and tactile discrimination

Answer: (A)

Dorsal column function is tested most directly by modalities that rely on the intact large-fiber pathways carrying fine touch, vibration, and proprioception to the brain. Vibratory sense and joint position sense are classic, straightforward measures of these pathways. Using a tuning fork on a bony area checks how well vibration information is transmitted, while asking a patient to identify the position or movement of a limb with eyes closed assesses proprioception. If these senses are impaired, it points toward dorsal column dysfunction.

In contrast, temperature and pain gauge the spinothalamic tract, which carries crude, fast pain and temperature signals, so abnormalities there suggest a different pathway issue. Light touch and pressure are less specific because they involve multiple pathways, and tactile discrimination relies on higher cortical processing after sensory input, not just the dorsal columns.

Thus, vibration and position sense best reflect dorsal column integrity.