Q) What does "meta-analysis" mean?
A) Meta-analysis is a technique to combine the results of several studies. For example we hope to be able to understand how brain structure is affected in bipolar disorder by pooling different studies which have measured the same structure in patients with bipolar disorder compared to a control group. For more information see the meta-analysis page in wikipedia.
Q) I'm having problems downloading the database, what's wrong?
A) Some problems are caused by the internet browser trying to open the files rather than save them. This problem may be solved by visiting our alternative download site. Be sure to right click on these links and choose "Save Target As..." (Internet Explorer) or "Save Link As.." (Firefox).
The largest file is 3Mb which may take time to download with some internet connections. If you are still having problems please contact us stating the name and version of your internet browser and the version of Excel you have. We will be happy to email you the files if all else fails.
Q) Can a brain scan tell if you have bipolar disorder?
A) No. With further research this may be possible in the future, but the differences we currently observe are small and can only be seen when we compare a large group of patients with bipolar disorder to those without the diagnosis. However these changes may give use clues to what cause the illness and further research is needed to help us understand this.
Q) Why isn't our study included in your database?
A) The database only includes studies which have compared patients with bipolar disorder to a control group from 1980 to October 2007. We have excluded studies which combined patients with major depressive disorder with bipolar patients. We have also not included Voxel Based Morphometry Studies (VBM) as it is difficult to include these in a traditional meta-analysis. If you still think your study should have been included please contact us.
Q) Did you have direct access to all the MRI scans that were included in the meta-analysis?
A) No, we used volume measures published by the different research groups. For example when investigating total brain volume we used the published values from 15 different studies which reported the average brain volume in patients with bipolar disorder and the average brain volume in a control group.
Q) I think I have found an error in your database.
A) Since publication no errors have been found in the database or meta-analysis. We have used a number of methods to reduce the chance of errors in the database, including double checking all data entered into the meta-analysis and having an independent investigator checking a large random sample of data. However if you think you have spotted an error please contact us.
Q) How do I cite your paper / online database?
A) Thanks for asking, when citing the meta-analysis or online database the reference is:
Kempton MJ, Geddes JR, Ettinger U, Williams SCR, Grasby PM (2008)
Meta-analysis,database and meta-regression of 98 structural imaging studies in bipolar disorder.
Archives of General Psychiatry 65(9) 1017-1032
Here are some made up examples of how you could cite us:
"In reviewing studies investigating the temporal lobe in bipolar disorder we consulted the Bipolar Disorder Structural Imaging Database (Kempton et al 2008). Increased volume of this structure was found by..."
"We combined the effect size found in our study with a meta-analysis of studies which have investigated the left putamen using the Bipolar Disorder Structural Imaging Database (BiND, Kempton et al 2008). This gave a combined effect size of...."
"As we found a negative correlation between total gray matter volume and illness duration in our sample we performed a meta-regression between these variables using the Bipolar Disorder Structural Imaging Database (Kempton et al 2008). The meta-regression was performed on 5 studies which measured total gray matter volume which reported mean illness duration. We detected a significant effect of illness duration on gray matter volume supporting our findings..."
Q) Do you have any other databases or websites?
A) Yes, I have been involved in creating:
-The Major Depressive Disorder Neuroimaging Database which is similar in design to this website but looks at Major Depression
-The MRI Brain Segmentation Testing Protocol which is a collection of 312 freely available MRI images to test segmentation algorithms
-ALVIN lateral ventricle segmentation which is an SPM8 extension for segmenting the lateral ventricles which has been tested using the above testing protocol
Q) What do the different sections in the meta-analysis spreadsheets mean?
A) Please see figure below:
Please see our press release regarding the meta-analysis for further information.
More questions and answers will appear here as we receive them....