Dipole Source Localization of Periodic Sharp Wave Complexes in Creutzfeldt-Jakob Disease

ABSTRACT

BACKGROUND: Patients with Creutzfeldt-Jakob disease (CJD) show periodic sharp wave complexes (PSWCs) on electroencephalography (EEG) during the course of their illness. However, the source location of PSWCs and the pathophysiological mechanism remains unclear. METHODS: Ten patients with sporadic CJD who showed typical PSWCs on EEG underwent brain magnetic resonance imaging (MRI) and positron emission tomography (PET, n=8) or single-photon emission computed tomography (SPECT, n=2) scans. A 30-second epoch from the EEG was selected for analysis. The recording was separated blindly using independent component analysis. The separate independent components were subjected to dipole source localization using a single dipole model. The source locations were compared with neuroimaging findings in each patient. RESULTS: Two to three independent components responsible for the PSWCs seen in CJD were identified. The EEG recording reconstructed from the selected independent components accounted for about 70% of the variance in the original recording. All but one patient had dipole sources localized in both cortical and subcortical areas. One patient had only subcortical dipole sources in both caudate nuclei. The cortical locations included the cingulate, insula, frontal, temporal, and occipital areas. The subcortical sources were located in the striate, thalamic, and subthalamic nuclei. All the dipole sources were localized within lesions seen as neuroimaging abnormalities. CONCLUSIONS: These results suggest that a subcortical mechanism, in addition to cortical structures, is involved in producing the generalized periodic discharges in CJD.