Transient Prosopagnosia after Right Chronic Subdural Hematoma Surgery: Top-Down Squash on Fusiform Gyrus or a Sign of Preexisting Dementia?

Face blindness, also called prosopagnosia, is the inability to recognize familiar faces and is often secondary to dysfunction of the fusiform gyrus. This symptom can be part of dementia or be related to a lesion in this anatomical structure. We present the case of a 78-year-old female patient, with a diagnosis of dementia without prosopagnosia, who developed an episode of transient loss of consciousness. A brain computed tomography scan revealed an extensive right hemispheric chronic subdural hematoma. Patient underwent urgent hematoma drainage after deterioration of the neurological condition, with sudden reduction of Glasgow Coma Scale. Postoperatively, patient developed inability to recognize the faces of family members for 48 hours. Transient prosopagnosia is an infrequent symptom in dementia. In this case, we hypothesized that, when involving right basal temporal structures, treatment of chronic subdural hematoma may determine a transient prosopagnosia. After hematoma drainage, the concavity of the fusiform gyrus and the inferior-medial surface of the temporal lobe might crush against the skull base, causing alterations of the microcirculation and temporary flow deficits at this level. We defined this phenomenon, onomatopoeically, "squash effect."