Which of the following is a characteristic symptom of ALS?

Muscle spasticity and hyperreflexia are characteristic symptoms of Amyotrophic Lateral Sclerosis (ALS). ALS is a progressive neurodegenerative disease that affects motor neurons in the brain and spinal cord. As the motor neurons degenerate, their ability to send messages to the muscles deteriorates, leading to muscle weakness and atrophy.

Spasticity occurs due to the inability of the affected motor neurons to control muscle movement properly, resulting in stiff and rigid muscles. Hyperreflexia, or exaggerated reflexes, can also be observed due to disruption in the normal feedback loop between the muscle and the nervous system. These symptoms are closely associated with the primary motor neuron degeneration seen in ALS, making them crucial for identifying the condition.

In contrast, fatigue, decline in vision, and severe headaches are not primary symptoms associated with ALS. Fatigue can occur in many conditions but is not specific to ALS. A decline in vision is more characteristic of conditions affecting the optic nerves or other parts of the visual pathway, rather than motor neuron degeneration. Severe headaches are generally linked to a variety of other pathologies and do not correlate with the typical symptom profile of ALS.