Tonic-clonic stats error sinks epilepsy paper

pm_cover_dez_01A brain imaging study in children with epilepsy has been retracted by the Journal of Magnetic Resonance Imaging due to a statistics error.

Here’s the notice for “Microstructural Brain Abnormalities of Children of Idiopathic Generalized Epilepsy With Generalized Tonic-Clonic Seizure: A Voxel-Based Diffusional Kurtosis Imaging Study”:

The above article, published online on 3 May 2014 in Wiley Online Library (, has been retracted by agreement between the authors, the journal Editor in Chief, and Wiley Periodicals, Inc. The retraction has been agreed due to errors in the results of the published article. The authors stated in the Methods section that ‘. . . only clusters with a false discovery rate (FDR)-corrected P-value less than 0.05 were included.’ However, it was subsequently discovered that the FDG-correction had not been performed correctly. Had this been carried out in the right way, the difference between the case group and the control group in most of the presented regions would have been insignificant.

Here’s the abstract:


To investigate the diffusion abnormalities in the brain of children with idiopathic generalized epilepsy (IGE) with generalized tonic-clonic seizure (GTCS) by using diffusion kurtosis imaging (DKI).

Materials and Methods

Twenty-one IGE children with GTCS and 16 controls were recruited. DKI was performed and maps of radial diffusivity (λ), axial diffusivity (λ//), mean diffusivity (MD), fractional anisotropy (FA), radial kurtosis (K), axial kurtosis (K//) and mean kurtosis (MK) were calculated. Voxel-based analyses were employed to compare diffusion metrics in epilepsy versus the controls.


In the case group, MD was found significantly higher in the right temporal lobe, the right occipital lobe, hippocampus, and some subcortical regions, while FA increased in bilateral supplementary motor area and the left superior frontal lobe (false discovery rate corrected P < 0.05). Analysis of λ and λ// showed that the increased MD was mainly due to the elevated λ//. Significantly decreased MK was also detected in bilateral temporo-occipital regions, the right hippocampus, the left insula, the left post-central area, and some subcortical regions (false discovery rate corrected P < 0.05). In most regions the changed MK were due to the decreased K//.


The kurtosis parameters (K, K//, and MK) reflect different microstructural information in the IGE children with GTCS, and this support the value of DKI in studying children GTCS

We’ve contacted the author and editor, and will update with any new information.

Hat tip: Rolf Degen.

One thought on “Tonic-clonic stats error sinks epilepsy paper”

  1. Probably the retraction notice warrants a correction as well: ” However, it was subsequently discovered that the FDG(FDR instead?)-correction had not been performed correctly.”

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