| A rare occipital epilepsy syndrome with onset most commonly between four and seventeen years (mean eleven years; range one to fifty years). Seizures are triggered by photic stimuli such as flickering sunlight. Focal sensory visual seizures which may evolve to bilateral tonic-clonic seizures are mandatory for the diagnosis. Focal sensory visual semiology includes colored spots, formed visual hallucinations, or visual blurring/loss that moves across the visual field. There is associated head and eye version. Seizures may progress to a cephalic sensation (including headache), autonomic epigastric sensation or vomiting, and impaired awareness or to a focal to bilateral tonic-clonic seizure. Seizures are typically brief (less than three minutes), although prolonged seizures may occur. Development and cognition are typically normal. Neurological examination is normal. The background electroencephalogram (EEG) activity is normal. Occipital epileptiform abnormalities facilitated by eye closure and intermittent photic stimulation are seen. Epileptiform activity is elicited by sleep deprivation and by sleep. MRI is normal or has nonspecific findings. |
