Meeting Banner
Abstract #1801

Evidence of non-normal distributions in brain imaging data from normal subjects: implications for diagnosis of disease

David Alexander Dickie 1 , Dominic E Job 1 , Joanna M Wardlaw 1 , David H Laidlaw 2 , and Mark E Bastin 1

1 The University of Edinburgh, Edinburgh, United Kingdom, 2 Brown University, Providence, RI, United States

The most commonly used statistical methods in brain imaging are parametric, i.e., assume data follow the normal (Gaussian) distribution. Whether or not structural brain MRI data follow the Gaussian distribution, and whether this actually matters, has yet to be determined. This work tested whether brain MRI volumes in a typically sized adult sample (n=80; 25-64 years) were Gaussian distributed. The impact of distribution shape on effect sizes between age groups was then determined. We found that these data were not Gaussian. This led to large, unsystematic errors in parametric effect sizes of normal ageing brain volumes.

This abstract and the presentation materials are available to members only; a login is required.

Join Here