Which form is most associated with dorsal midbrain syndrome?

• A. Spasmus nutans
• B. Convergence-retraction syndrome
• C. Rotational nystagmus
• D. Gaze-evoked nystagmus

Answer: (B)

Dorsal midbrain syndrome presents with vertical gaze abnormalities and other signs from disruption of the dorsal midbrain pathways that control upward eye movements. The sign most closely tied to this syndrome is convergence-retraction syndrome. In this pattern, when the patient attempts to look upward, the eyes repeatedly converge and retract into the orbit. This reflex-like movement reflects loss of the dorsal midbrain’s vertical gaze control, so the eyes fail to elevate properly and instead show the convergence-retraction response.

Other forms of eye movements listed don’t specifically point to dorsal midbrain dysfunction. Spasmus nutans is an infantile syndrome with nystagmus and head nodding, not the vertical gaze-palsy pattern of Parinaud’s syndrome. Rotational nystagmus is a broad finding seen in various conditions and isn’t characteristic of dorsal midbrain syndrome. Gaze-evoked nystagmus arises from inability to maintain an eccentric gaze and is more associated with different brainstem or cerebellar problems, not the classic dorsal midbrain pattern.