Abstracts

Rationale: Well-planned, statistically definitive studies have been performed detailing Electroencephalography (EEG) and Magnetic Resonance Imaging (MRI) abnormalities in sporadic Creutzfeldt-Jacob disease (CJD) within European, Australian, and Canadian populations ¹. However, no comparable study has been performed for the US. The significantly greater heterogeneity of the US population, and the potential interaction of this heterogeneity with different molecular subtypes of CJD (each having its own set of sensitivity profiles for EEG and MRI ²), support the importance of studying the sensitivities of EEG and MRI within US-based sporadic CJD cases. In preparation for such a study, we have conducted a meta-analysis of the existing literature for US-restricted CJD. Methods: Searches of the US National Library of Medicine were performed using the following search criteria: “CJD and EEG and USA” and “CJD and MRI and USA”. After excluding the second incidence of some studies, articles that did not mention specific numbers of patients, articles that lacked specific data regarding test results, and an article that did not distinguish results between US and European patients, 20 articles remained comprising a total of 36 patients. EEG positivity was defined as presence of periodic sharp waves. MRI positivity was defined as presence of T2/Fluid attenuated inversion recovery (FLAIR) and Diffusion Weighted Imaging (DWI) hyperintensities in either putamen or caudate. Data was analyzed using Fischer exact test, 2-tailed. Results: Twenty of 29 (69%) cases had positive EEGs. Ten of 27(37%) patients had positive MRI findings. Findings within combined European, Australian, and Canadian populations were 58.4% and 39.1% for EEG and MRI abnormalities, respectively1. Comparison to these findings using Fisher’s exact test revealed no statistically significant difference for MRI findings (p=1.00) or EEG findings (p=0.3428). Conclusions: Results of this meta-analysis indicate that EEG and MRI sensitivities in US-based sporadic CJD cases are not significantly different from those sensitivities reported in other populations studied. However interpretation of these findings is limited by the fact that some of the data included within this meta-analysis were derived from case reports which by their nature are marked by atypical disease courses. A more definitive study of all US-based sporadic CJD cases with EEG and MRI data remains to be conducted. References: ¹ Collins SJ, Sanchez-Juan P, Masters CL, et al. Determinants of diagnostic investigation sensitivities across the clinical spectrum of sporadic Creutzfeldt-Jakob disease. Brain 2006 Sep;129(Pt 9):2278-87. ² Mendonça RA, Martins G, Lugokenski R, Rossi MD. Subacute spongiform encephalopathies. Top Magn Reson Imaging. 2005 Apr;16(2):213-9. Review.