Which of the following is a key sign of a stroke during a field assessment?

A sudden onset of severe headache, particularly if described as the "worst headache of the patient's life," is a notable sign of a stroke, especially in the context of a hemorrhagic stroke. This type of stroke is caused by a rupture of a blood vessel in the brain, leading to bleeding. The sudden nature of the headache can indicate that a significant and acute neurological event is occurring. Additionally, this symptom is often marked by rapid onset and intensity, aligning with the characteristics of a stroke, where time is critical for effective treatment.

Recognizing this sign during a field assessment is essential in identifying a potential stroke, allowing for prompt medical intervention that can significantly improve outcomes. In contrast, the other options may indicate various other medical conditions or states, but they are not directly indicative of stroke. For instance, continuous coughing may suggest respiratory issues rather than neurological problems, while elevated blood pressure and rapid heartbeat can occur in numerous health conditions, including strokes, but are less specific in isolation. Therefore, the sudden onset of severe headache stands out as a key indicator during an assessment for strokes.