ABSTRACT

OBJECT: Subcortical electrical stimulation during brain surgery may allow localizing functionally crucial white matter fibers and thus tailoring of the tumor resection according to its functional limits. The arcuate fasciculus (AF) is a white matter bundle connecting frontal, temporal and parietal cortical areas that is often disrupted by left brain lesions. It plays a critical role in several cognitive functions related to phonological processing but current intraoperative monitoring methods do not yet allow mapping of this tract with sufficient precision.

METHODS: In this report, we studied twelve patients undergoing awake brain surgery for tumor resection which was related to the risk of AF damage. In order to preserve AF integrity and the cognitive processes sustained by this tract in the intrasurgical context, we used real word (WR) and non-word (NWR) repetition tasks as complements to the standard picture naming.

RESULTS: The present results show that the NWR task allowed subtle detection of errors possibly related to AF alterations when compared to the errors identified by WR or picture naming. Moreover, only three patients presented phonological paraphasias in standard picture naming, and in two of these patients it co-occurred with the total loss of word- and non-word repetition ability. Before surgery, the volume of the patients’ lesions predicted NWR performance.

CONCLUSIONS: We suggest that monitoring NWR intraoperatively may complement the standard naming tasks and could permit better preservation of the important language-production functions subserved by the AF.