Passive language mapping with magnetoencephalography in pediatric patients with epilepsy

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>Functional mapping is important for determining surgical candidacy and also in epilepsy surgery planning. However, in young children and uncooperative patients, language mapping has been particularly challenging despite the advances in performing noninvasive functional studies. In this study the authors review a series of children with epilepsy who underwent language mapping with magnetoencephalography (MEG) while sedated or sleeping, to determine receptive language localization for presurgical evaluation.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>The authors undertook a retrospective review of patients who underwent MEG between December 2007 and July 2009, and identified 15 individuals who underwent passive language testing as part of their presurgical evaluation because they were unable to participate in traditional language testing, such as Wada or functional MRI. Factors necessitating passive language testing included age and neurocognitive development.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>Three of the 15 patients were deemed candidates for epilepsy surgery based on the results from standard preoperative testing, including video electroencephalography, MRI, and passive receptive language testing using MEG technology. The MEG studies were used successfully to localize language in all 3 patients, creating opportunities for seizure freedom through surgery that would not otherwise have been available. All 3 patients then underwent resective epilepsy surgery without experiencing postoperative language deficits.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>This case series is the first to look at language mapping during sleep (passive language mapping) in which MEG was used and is the first to evaluate passive language testing in a patient population with intracranial pathological entities. This case series demonstrates that MEG can provide an alternative method for receptive language localization in patients with barriers to more traditional language testing, and in these 3 cases surgery was performed safely based on the results.</jats:p></jats:sec>

Assessment of hemispheric dominance for receptive language in pediatric patients under sedation using magnetoencephalography

“…More recently, Lai et al (2012) derived brain activation maps outlining cortical regions underlying speech and song perception in a group of low-functioning autistic children under light propofol sedation using passive auditory stimulation during fMRI. In addition, similar success was observed by Van Poppel et al (2012) for the purpose of establishing hemispheric dominance for receptive language with MEG using a passive language mapping protocol in a series of 15 patients while under either sedation or during natural sleep (Stage I/II), three of whom exhibited no subsequent postoperative language deficits.…”

“…Specifically, it has been reported that children under propofol sedation exhibit patterns of left hemisphere activation in response to auditory linguistic stimuli comparable to those observed in non-sedated individuals (Souweidane et al, 1999; Gemma et al, 2009), with others reporting similar patterns among sedated and non-sedated children during song, as well as speech, perception (Lai et al, 2012). Furthermore, the utility of passive language mapping with MEG has also been demonstrated recently in small series of cases, with the observation that patients undergoing subsequent resective surgery for epilepsy show no evidence of postoperative language deficits (Van Poppel et al, 2012). …”

Is it time to replace the Wada test and put awake craniotomy to sleep?

“…Thus CSM and the Wada cannot be used with patients with attention deficit and hyperactivity problems, patients in a state of confusion, patients with encephalopathies, or patients who are very young. None of these limitations apply to neuroimaging, where localization of sensory, motor, and even receptive language cortex can be accomplished with the patient under sedation …”

Magnetoencephalography for Clinical Pediatrics: Recent Advances in Hardware, Methods, and Clinical Applications

“…The clinical pediatric applications of MEG have been extensively reviewed elsewhere. [6][7][8][9][10][11][12][13][14][15] In these reports, it is noted that MEG is a valuable component of the diagnostic armamentarium for patients with medically refractory epilepsy. In particular, the ability to noninvasively localize ictal onset zones (IOZ) and their anatomic relationships to eloquent functional cortices allows the pediatric epilepsy team to more accurately assess both the likelihood of postoperative seizure freedom and the likelihood of functional deficits that may arise following resective surgery.…”