Characterization of the basal temporal language area

ABSTRACT

Basal temporal language area (BTLA), demonstrated by electric stimulation of the cortex in epilepsy patients rarely cause significant language problems after it resection. Recently, we experienced a patient who developed severe language deficits after the resection of BTLA. To characterize the language function of BTLA we compared the language characteristics in our patient with those of the previously reported characteristics of BTLA observed by either its resection or electrical stimulation. The BTLA was thought to play a major function in access to naming pool and in the comprehension partly through Wernicke's area. Also the visually associated language function, reading aloud and reading comprehension were known to be more damaged than visually unassociated function. Previous studies showed that BTLA identified by electrical stimulations in patients with epilepsy was usually found to be clinically insignificant for only minor and transient ]anguage deficits being noticed after its surgical resection with only rare exceptions. Our patient developed severe language deficits which lasted for at least several weeks after the resection of the epileptogenic lesion located in the BTLA. She had a calcified granuloma in inferior temporal gyrus and the WADA test in this patient revealed a strongly lateralized language and memory function to the resected temporal lobe. The precise neural mechanisms of severe language deficits found in this patient in unclear, however, our experience suggest that BTLA is involved in the language function to a significant degree at least in some patients. Further prospective investigations to preoperatively identify the patient group at risk of developing severe language deficits after the resection of BTLA are needed.