2706
Symposium
Invasive methods of brain mapping are an established part of the clinical management of conditions like epilepsy and brain tumours. Neurology/neurosurgery programs worldwide are, however, actively seeking non-invasive methods as safer and reliable alternatives, and to guide the use of invasive procedures where required. To this end, functional neuroimaging methods (fMRI, SPECT) and non-invasive brain stimulation (TMS) methods are ideal candidates. However, there is a lack of consensus in the clinical and the imaging community as to when the use of these non-invasive methods is indicated or how to integrate their findings in clinical decision making. This timely symposium will address the recent advances in fMRI and TMS technology and their usefulness in preoperative localization of seizure onset zone and eloquent cortices in children and adults who are being evaluated for epilepsy/brain tumor surgery. This scientific symposium will also address the gaps in knowledge that currently exists with regards to the neurophysiological principles of the above methods and their integration into patient care. The discussants will use case studies to demonstrate the clinician’s point of view on integrating the findings from these non-invasive mapping with those from invasive mapping methods into presurgical evaluation and planning.
Following attendance at this symposium individuals should be able to:
1. Contrast the strengths and weaknesses of different brain mapping approaches in different age cohorts (e.g. paediatrics vs adults)
2. Evaluate the suitability of different brain mapping approaches to the specific patient groups with which they work
3. Identify areas ripe for further methods development in order to address unmet clinical needs (e.g. task fMRI for predicting post-operative cognitive change)
Methods development teams (from graduate students through to senior academics) and clinicians across a range of specialities (epilepsy, stroke, neurosurgery, movement disorders, dementia, paediatrics, neuropsychology, psychiatry, neurology, cognitive neuroscience).
Presentations
Language fMRI is increasingly used in the presurgical evaluation of epilepsy and tumor patients, but its use nonetheless remains limited by the need for specialized expertise in data acquisition, processing and interpretation. The Australian Epilepsy Project (AEP) is a national scale research project collecting imaging, cognitive and genetics data in up to 4,000 participants, with language fMRI collected across multiple sites and reported back to referring neurologists. To achieve this, the AEP has developed standardized methods for data acquisition, processing, and interpretation. This includes telehealth-based cognitive task training for participants, a centralized data processing pipeline, automated analysis of language laterality, and manual review of cases flagged as atypical upon automated review. This approach makes language fMRI a widely accessible clinical tool, expanding its use beyond specialized centers to a broader patient population.
Presenter
Chris Tailby, The Florey Heidelberg, Victoria
Australia
Accurate presurgical mapping of motor, speech, and language cortices, while crucial for neurosurgical planning and minimizing post-operative functional deficits, is challenging in young children with neurological disease. In such children, both invasive (cortical stimulation mapping) and non-invasive functional mapping imaging methods (MEG, fMRI) have limited success, often leading to delayed surgery or adverse post-surgical outcomes. Transcranial magnetic stimulation (TMS) is a safe, reliable, and effective tool to map eloquent cortices in young children. In this talk I will review the experience of our and other centres with regards to the clinical utility of TMS in young children with refractory epilepsy or brain tumors. Using TMS, both normal motor, speech, and language developmental patterns and apparent disease induced reorganization have been demonstrated in this young cohort. The successful localization of motor, speech, and language cortices in young children improves the understanding of the risk-benefit ratio prior to surgery and facilitates surgical planning aimed at preserving motor, speech, and language functions.
Functional magnetic resonance imaging (fMRI) has influenced our understanding of cognition in epilepsy throughout the lifespan. Clinical fMRI provides reliable, noninvasive guidance of cognitive functioning and plays a growing role in the epilepsy pre-surgical evaluation. Subdural mapping and stereoelectroencelphalography (sEEG) are additional methods of functional mapping that can provide valuable information regarding functional brain networks in the context of seizure activity. In this talk I will review our application of functional magnetic resonance imaging (fMRI) of memory and language, subdural mapping, and stereoelectroencelphalography (sEEG) in the setting of paediatric epilepsy surgery. Successful application of these methods requires consideration of important sociocultural factors such as age, cognitive ability and bilingualism, all of which need to be incorporated into functional mapping methods and case conceptualization.
Presenter
Leigh Sepeta, Children's National Washington DC, DC
United States
Epilepsy surgery can be an effective treatment option for drug resistant focal epilepsy. For surgery to occur, though, the epileptogenic focus must first be localised. Historically this has been based upon investigations such as seizure semiology, EEG, structural MRI, PET and SPECT imaging. Invasive procedures such as stereo EEG can also be used to further refine localisation, however such invasive procedures should only occur in the context of a strong localisation hypothesis. This talk will review novel, individualised approaches to identifying the seizure onset zone in otherwise difficult to localise drug resistant focal epilepsy, using specific case examples to illustrate salient points. This includes the use of patient specific task fMRI paradigms (e.g. in-scanner toothbrushing in reflex toothbrushing epilepsy), patient specific seizure induction manoeuvres enabling ictal SPECT (e.g. roller-coaster epilepsy), and applications of simultaneous EEG-fMRI to identify candidate seizure onset zones for subsequent exploration via SEEG implantation.
Presenter
David Vaughan, The Florey Institute of Neuroscience and Mental Health Heidelberg, Victoria
Australia