A 70-year-old man with atrial fibrillation develops sudden cortical blindness. MRI shows bilateral occipital lobe infarcts. Pupillary light reflexes are intact. He can perceive moving objects but not stationary ones. This is called:
- A Anton syndrome
- B Balint syndrome
- C Riddoch phenomenon ✓
- D Gerstmann syndrome
Correct answer: C. Riddoch phenomenon
Explanation
The Riddoch phenomenon is the ability to perceive moving objects in a field of cortical blindness while stationary objects remain invisible. It occurs with occipital lesions and indicates some preserved visual processing in area V5/MT. Anton syndrome is denial of blindness. Balint syndrome involves simultanagnosia and optic ataxia. Gerstmann syndrome involves finger agnosia and left-right disorientation.
Reference: Clinical Neuroanatomy, 28th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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