Which of the following is NOT a standard arousal stimulus described for comatose patients?

• A. Trapezius squeeze
• B. Nailbed pressure
• C. Sternal rub
• D. Visual pursuit test

Answer: (D)

Arousal in a comatose patient is assessed using provocative, noxious or tactile stimuli designed to provoke wakeful responses without requiring complex processing. Trapezius squeeze, nailbed pressure, and sternal rub are classic examples of these stimuli because they reliably trigger gross motor or withdrawal responses through brainstem and spinal pathways, helping gauge the level of wakefulness.

Visual pursuit, on the other hand, is a higher-level eye movement test that evaluates cortical and brainstem oculomotor function and conscious tracking rather than simply provoking arousal. It requires intact cortical processing to smoothly follow a moving target, so it isn’t used as a standard arousal stimulus. Therefore, the visual pursuit test is not a standard arousal stimulus described for comatose patients.