Which semiology most strongly suggests an occipital lobe focus in focal seizures?

• A. Motor symptoms limited to the face.
• B. Auditory hallucinations.
• C. Seizures with generalized onset.
• D. Visual phenomena such as flashing lights, formed visual hallucinations, homonymous visual field deficits early in the aura.

Answer: (D)

Visual processing happens in the occipital lobe, so seizures that begin there typically produce visual symptoms as the first sign. Flashes, formed visual hallucinations, and especially early visual disturbances that affect the same side of the visual field in both eyes (homonymous visual field deficits) point to involvement of the occipital cortex and its connections. In contrast, motor symptoms limited to the face suggest the frontal motor cortex, auditory phenomena point to the temporal lobe, and generalized onset indicates widespread network involvement. So the presence of visual phenomena with an early aura and homonymous field loss best localizes the focus to the occipital region.