Synchronized presentation of a language task to the electrical stimulation of cortical regions during speech mapping in an awake surgery

Abstract

Intraoperative speech mapping is performed to preserve language function during tumour resections that involve eloquent cortical areas. For this technique the synchronization of the picture presentation to the patient with the electrical stimulation of the cortex is of major importance. During the operative routine images are manually presented by a psychologist or neurologist to the patient and have to be coordinated with the neurosurgeon stimulating the cortex by a neurostimulator, operated by an engineer. To increase the efficiency of this procedure and to minimize the time needed to localize functional cortical areas, images should appear automatically with electrical stimulation. To achieve this synchronization, the potential combination of an existing neurostimulator with commercially available software for image display was studied. A trigger signal was created to induce the presentation of a series of line drawings showing different objects. The software to control the neurostimulator and the software for image displaying were installed on two different computers. A cable was developed to transfer the trigger signal from the neurostimulator to the computer used for picture presentation. It was shown that it is possible to induce the image display via the neurostimulator using square-wave pulses of 5 V and a width of 10 ms. Thus, we present a system that enables the automated picture presentation synchronized to the electrical stimulation of cortical regions.

Keywords

• intraoperative speech mapping
• direct cortical electrical stimulation