Teaching Video NeuroImages: Susac syndrome's acute onset callosal disconnection

A 59-year-old right-handed hypertensive diabetic and previously alcoholic man presented acute confusional state followed by apathy, dysexecutive syndrome, clumsy left hand, and apraxic gait. A year later, his wife noticed impaired hearing. Neurologic examination revealed marked callosal apraxia (nondominant limb ideomotor apraxia, disconnection variant) and left stereoagnosis due to callosal disconnection (video). Left hand agraphia was present without aphasia. MRI showed punched out holes through corpus callosum, sparing the calloso-septal interface (figure 1). Audiometry revealed left neurosensorial loss. Fluorescein retinography demonstrated hyperfluorescence of arterial vessel wall (figure 2), confirming the hypothesis of Susac syndrome.(1)