Positron emission tomography in patients with psychogenic non-epileptic seizures.

Abstract

Dear editor We have read with interest the recent review entitled “Uncovering the etiology of conversion disorder: insights from functional neuroimaging” by Maryam Ejareh dar and Richard AA Kanaan,1 published in Neuropsychiatric Disease and Treatment. Our paper on resting state brain metabolism measured by positron emission tomography (PET) was included and discussed.2 We were most surprised to see that the authors of the review seem to have misunderstood the findings of our study, which concerned patients with psychogenic non-epileptic seizures (PNES). The authors state that the 16 patients included in our study “were later found to have PNES with comorbid epilepsy”. This is incorrect, since our study included only patients with PNES in whom comorbid epilepsy was excluded. This crucial point is indeed detailed in the Methods section of our article and clearly stated in the abstract: “in all patients, the diagnosis was subsequently confirmed to be PNES with no coexisting epilepsy.” It is thus on the basis of incorrect understanding of our results that Drs Ejareh dar and Kanaan discuss the possible significance of hypometabolism in the anterior cingulate region described in our paper, and erroneously suggest that interpretation of PET findings is complicated by coexistent epilepsy, which was not in fact the case. We certainly agree with the authors regarding the importance of reviewing the literature on this complex subject, and the need for further studies with more rigorous methodology. However a basic step is of course to read in detail the existing works and avoid dissemination of misinformation. Given the high standards of your journal and its interest in advancing knowledge in the field of neuropsychiatry, we would expect that this error be corrected in print, to avoid confusion.