Paradoxical giftedness and memory decline after anterior communicating artery aneurysm clipping: A high-resolution MRI case report.

Amnesia is a well-documented complication following surgical repair of anterior communicating artery (ACoA) aneurysms. 3D MRI has clarified that it is primarily caused by infarction of the subcallosal artery, the largest unpaired perforating branch of the ACoA. Bilateral infarction of the columns of the fornix, a core component of the Papez circuit, has been identified as the anatomical basis of such amnesia. Another perforating artery prone to surgical injury is the recurrent artery of Heubner (RAH), which arises from the A1 to A2 junction of the anterior cerebral artery and is usually present bilaterally. When RAH infarction co-occurs with subcallosal artery infarction during ACoA aneurysm surgery, memory impairment may be accompanied by reduced processing speed and a worse long-term outcome. We report a 63-year-old man who underwent surgical clipping for a ruptured ACoA aneurysm. 3D-MR images obtained 10 months postoperatively revealed bilateral infarctions in the subcallosal artery territory, including the columns of the fornix, as well as a right-sided infarction in the RAH territory. Clinical correlation showed that these findings matched the patient's paradoxical cognitive profile, confirmed by formal neuropsychological testing 5 years after clipping. He demonstrated a dissociation between exceptionally gifted-level intellectual ability and comparatively lower scores in memory and processing speed. His full-scale intelligence quotient (IQ) was 144, with a verbal IQ of 156 and working memory of 150, while his general memory score was 115 and processing speed was 110. Although these latter scores fell within the high-average range, they represented a meaningful decline relative to his potential. This profile supports a dual circuit model: Subcallosal artery infarction disrupts the Papez circuit, impairing memory, while RAH infarction contributes to inefficiency through frontostriatal disconnection. This case of paradoxical giftedness with memory decline underscores the value of 3D MR imaging in revealing memory decline masked by cognitive reserve.