Susac Syndrome with Frontal Intermittent Rhythmic Delta Activity (FIRDA)

Abstract

Susac syndrome is a rare condition involving the brain, retina, and cochlea. Electroencephalogram (EEG) findings from published case reports show mainly generalized slowing. A 30-year-old man presented with acute onset of superior vision loss, unsteady gait, and hearing loss. This was accompanied by short-term memory loss and behavioral and mood changes. MRI showed multiple white matter hyperintensities. The EEG showed frontal intermittent rhythmic delta activity. A diagnosis of Susac syndrome was made and treatment with methylprednisolone, ASA, and Nimodipine was instituted. At one-year follow-up, bilateral hearing loss, mild visual impairment, and mood changes were still apparent. Frontal intermittent rhythmic delta activity can be seen in Susac syndrome.