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faq

 

Q: Who are the current co-chairs of ENIGMA-Epilepsy? 

A: ENIGMA-Epilepsy is currently led by Professor Sanjay Sisodiya of University College London and Professor Carrie McDonald of the University of California, San Diego. Dr. Christopher Whelan, who co-founded and co-led the group during his post-doctoral studies at the University of Southern California, currently serves as a part-time co-chair. Our DTI project is co-led by Dr. Sean Hatton (UCSD) and Professor Carrie McDonald. Several secondary projects have been initiated and co-led by additional ENIGMA-Epilepsy members, and are detailed here.

 

Q: Has ENIGMA-Epilepsy published any research papers? 

A: Yes. Our large-scale analysis of grey matter abnormalities across the common epilepsies was published in Brain. Several follow-up studies are currently ongoing.

 

Q: Since the gray matter study is now published, is it too late to contribute T1 scans?

A: No – groups are still welcome to process their T1 images, which will allow them to contribute to one of our ongoing secondary projects.

 

Q: Is ENIGMA-Epilepsy funded by research grants? 

A: Our initial projects were not directly funded by a dedicated research grant. However, our first study of grey matter abnormalities was indirectly supported by an NIH ‘Big Data 2 Knowledge’ grant, as well as dozens of additional grants, detailed in the Funding section of our Brain paper.

 

Q: What version of FreeSurfer should I use for volumetric analysis?

A: Please use version 5.3.

 

Q: I have T1-weighted images (for ENIGMA-Epilepsy: Volumetrics) but I do not have diffusion images. Will this be a problem? 

A: Not at all. It is often the case that certain groups can contribute to the FreeSurer project but not the DTI project. Simultaneous participation in ENIGMA-Epilepsy: Volumetrics and ENIGMA-Epilepsy: DTI is entirely optional.

 

Q: My patient group is much larger than my control group (or vice versa). Will this bias the meta-analysis? 

A: No. Our meta-analysis algorithms were developed to take this into consideration. Generally, once you have at least 20 participants in each test cohort, then this will not bias the ultimate meta-analysis.

 

Q: Should I stratify my patients into different groups before I start analysis?

A: No – there is no need to stratify your patient groups until you have produced the LandRVolumes.csv file. You can simply delete / reorganize patients in this LandRVolumes.CSV file, based on their subject ID.

 

Q: Why are we including patients with tumors, lesions, intracranial infection, malformations and other abnormalities?

A: For now, we will pursue the tried and tested ENIGMA paradigm: commencing with a broad analysis before progressing onto more specific studies. This has worked extremely well for other ENIGMA working groups (see: ENIGMA-Schizophrenia, ENIGMA-MDD, ENIGMA-Bipolar Disorder) and will allow us to search for potential ‘low-hanging fruits’ before considering more granular syndromic classification, and retains maximum power for shared changes and shared genetic influences. Most patients with obvious structural changes will be excluded after quality inspection of subcortical and cortical segmentations, as in most cases FreeSurfer fails to segment visibly abnormal brain regions.

 

Q: Why are we only studying adult forms of epilepsy?

A: The general consensus in the brain imaging community is that participants older than 55 years of age may show signs of brain degeneration, whereas the brains of pediatric / adolescent participants may not be fully developed. Groups with MRI scans from childhood cases are encouraged to process their data alongside the rest of the consortium, as we will investigate childhood-onset forms of epilepsy as part of a follow-up study.

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