Which of the following is an upper motor neuron sign in ALS?

• A. Fasciculations
• B. Atrophy
• C. Hypotonia
• D. Spasticity and hyperreflexia

Answer: (D)

ALS affects both upper and lower motor neurons, so patients show a mix of signs. Upper motor neuron signs arise from loss of inhibitory control over the spinal cord, leading to increased tone and reflexes. Spasticity reflects that increased muscle tone, while hyperreflexia indicates exaggerated deep tendon reflexes. These are classic UMN features in ALS. In contrast, fasciculations and muscle atrophy come from lower motor neuron loss (motor neuron cell bodies and their axons), presenting as twitches and wasting. Hypotonia is decreased tone, which is more typical of LMN damage or certain acute states, not an UMN sign. So the combination of spasticity and hyperreflexia best represents an upper motor neuron sign in ALS.