Subjective visual symptoms and electroencephalographic analysis before and after removal of occipital falx meningioma

A 41-year-old patient underwent surgery for the partial removal of a posterior falx meningioma, which invaded deeply into both occipital lobes. After surgery, the patient complained of marked metamorphopsia, colored photopsia, afterimage and loss of stereopsia. The relationships between these symptoms and features of the VEP and EEG power spectra (both under resting and photic driving conditions) were investigated. Marked photopsia on the 4th postoperative day was accompanied by EEG features indicating asynchronous excitation of injured cortical cells, while the presence of a strong afterimage on days 17 through 24 coincided with indications of an apparent refractoriness in cortical activation.