New Tests for Language Mapping with Intraoperative Electrical Stimulation of the Brain to Preserve Language in Individuals with Tumors and Epilepsy: A Preliminary Follow-Up Study

Intraoperative Electrical Stimulation (IES) of the brain is performed to localise and spare language functional areas before extraction of brain tissue in patients with tumors and epilepsy. The procedure is very precise and highly effective. Yet, it is argued that language tests used during IES are too limited. This article presents new language tests that have a potential of minimising post-operative risk to language function. It is a continuation of a previous study (Połczyńska 2008) and it contains extended versions of earlier presented tests, as well as new tests designed in three sets: (1) Grammar-focused tests for the dominant left hemisphere, (2) Non-dominant righthemisphere tests and (3) Tests for the subcortex. To assure maximum safety and efficiency of the tests before they are used during IES for the first time, it is suggested that they are first used with patients with intractable epilepsy who have a multielectrode subdural grid implanted onto their cortex to trace the source of seizures. The subdural grid gives a chance to carry out an electrical stimulation of those areas of the cortex which are covered with a grid. This type of language mapping is carried out in a ward and is not time-limited.