Abstracts

Rationale: To date, there is limited understanding of the role of the precuneus and only functional MRI studies have suggested its involvement in a wide spectrum of highly integrated tasks, including spatially guided behavior and visuo-spatial imagery. Positive phenomena such as seizures arising from the precuneus would provide further insight in its function. Methods: We present a patient with intractable parietal lobe epilepsy arising from with a T2 hyperintense, heterogeneous lesion localized to the right mesial parietal cortex, anterior to the parieto-occipital sulcus. Two seizure types with distinct semiologies were described and captured on video EEG monitoring. Video analysis and EEG analysis elucidated the precise seizure semiology and the location of the ictal and interictal activity, respectively. Results: Our patient, a 9-year-old boy, presented with a complaint of ill-defined, paroxysmal "dizziness". With video EEG monitoring, two seizure types were clarified. The first seizure type consisted of an urge that the patient described as a "feeling of wanting to move". On video analysis, the patient is seen to turn his head and body to his left. He remains conscious and alert. He is able to answer questions coherently and when asked he can look to his right and turn away from his left. This seizure was associated with an ictal pattern localized to the right parieto-occipital region. The second seizure type consisted of reading induced visual distortion with macropsia and micropsia described as words jumping out of the page. This seizure type was not associated with any significant EEG change; however, these symptoms abated with adjustment of the anti-epileptic medications. Interictally, intermittent rhythmic slowing and spike were seen and localized to the parietal midline (max Pz) and the right parieto-occipital regions. Conclusions: Our patient presents with a novel seizure semiology consisting of an urge to move to his left and reflex seizures consisting of reading induced visual distortions. The interictal and ictal findings correlate with the location of the right precuneal lesion and therefore the positive phenomenon from the seizures suggest the precuneus' role in visuospatial information processing and spatial imagery.