Which of the following symptoms indicates anterior circulation involvement?

Facial asymmetry is a clear indicator of anterior circulation involvement, particularly when considering the arterial supply to the brain. The anterior circulation, which includes the internal carotid arteries and their branches, plays a significant role in supplying blood to the frontal, parietal, and some parts of the temporal lobes—areas responsible for motor control and sensory processing of the face.

Facial asymmetry is often associated with strokes or ischemic events affecting the territories supplied by these arteries. For instance, if a stroke affects the parts of the brain responsible for facial muscle control on one side, this can lead to noticeable facial drooping or asymmetry. Thus, observing facial asymmetry can be a critical sign of anterior circulation impairment.

In contrast, other symptoms like ataxia, drop attacks, and syncope might suggest involvement of different brain regions or vascular territories. Ataxia, for instance, is typically associated with posterior circulation issues, as it relates to balance and coordination controlled by the cerebellum. Drop attacks are indicative of sudden loss of tone, which may not specifically point to anterior circulation problems. Syncope, or fainting, can result from various conditions affecting blood flow to the brain and is not specifically localized to anterior circulation involvement.