Which of the following is NOT a symptom of spinal nerve involvement in ALS?

• A. Reduced reflex response
• B. Increased muscle agility
• C. Atrophy in muscles
• D. Weakness in extremities

Answer: (B)

In the context of amyotrophic lateral sclerosis (ALS) and spinal nerve involvement, increased muscle agility is not a symptom associated with this condition. ALS typically leads to the degeneration of motor neurons, which results in muscle weakness and atrophy. As the motor neurons that stimulate muscle contractions are affected, individuals may experience reduced reflexes and noticeable weakness in their extremities due to the lack of signal transmission to the muscles.

Atrophy in the muscles is a direct consequence of denervation and disuse, as the muscles are no longer receiving sufficient neural input. Therefore, while decreased reflex response, muscle atrophy, and weakness in extremities are all common signs of the disease due to the effects on the spinal nerves, muscle agility would actually decrease, not increase, as the condition progresses. This understanding highlights the mismatch of muscle function expected with ALS and reinforces that the correct answer identifies an option that does not align with the symptoms typically observed in such cases.