Which of the following is a common indicator or symptom of meningitis?

Brudzinski's sign is indeed a common indicator or symptom of meningitis. This clinical sign is observed during a physical examination when the healthcare provider flexes the patient's neck while the patient is lying down. A positive Brudzinski's sign occurs when this maneuver causes involuntary flexion of the knees and hips, indicating irritation of the meninges, which is often associated with meningitis.

Meningitis, an inflammation of the protective membranes covering the brain and spinal cord, can present with a variety of symptoms, including fever, headache, and neck stiffness. Brudzinski's sign is particularly significant as it demonstrates the body's reaction to potential meningeal irritation.

While the other options represent various conditions or symptoms, they do not specifically indicate meningitis. Cephalalgia, or headache, is a general symptom that can occur in many conditions, not exclusive to meningitis. Sciatica is related to nerve pain along the sciatic nerve and narcolepsy is a sleep disorder, neither of which relate directly to the inflammation indicative of meningitis. Thus, Brudzinski's sign stands out as a specific and significant indicator for this condition.