Which statement accurately describes ALS?

• A. Affects only sensory neurons.
• B. Affects autonomic neurons leading to blood pressure changes.
• C. Degeneration of upper and lower motor neurons.
• D. Affects cranial nerves only.

Answer: (C)

ALS is a motor neuron disease in which both the brain’s upper motor neurons and the spinal cord/brainstem’s lower motor neurons progressively degenerate. This dual loss disrupts voluntary movement in two ways: upper motor neuron damage causes spasticity, weakness, and exaggerated reflexes, while lower motor neuron loss leads to flaccid weakness, muscle atrophy, and fasciculations. Because both systems are affected, people develop a mixed picture of motor impairment rather than problems limited to sensation or to a single nerve type. Sensory pathways are typically spared, autonomic changes are not the defining feature, and ALS is not limited to cranial nerves; it commonly involves limbs as well as bulbar muscles. The description that emphasizes degeneration of both upper and lower motor neurons best captures the condition.