Non-invasive alternatives to the Wada test in the presurgical evaluation of language and memory functions in epilepsy patients

The cognitive outcome of the surgical removal of an epileptic focus depends on the assessment of the localisation and functional capacity of language and memory areas which need to be spared by the neurosurgeon. Traditionally, presurgical evaluation of epileptic patients has been achieved by means of the intracarotid amobarbital test assisted by neuropsychological measures. However, the advent of neuroimaging techniques has provided new ways of assessing these functions by means of non-invasive or minimally invasive methods, such as anatomical and functional magnetic resonance imaging, positron emission tomography, single-photon emission computed tomography, transcranial magnetic stimulation, functional transcranial Doppler monitoring, magnetoencephalography and near infrared spectroscopy. This paper aims at comparing and evaluating the traditional and recent preoperative approaches from a neuropsychological perspective.