It is unclear which patients with PLEDs will have associated seizures and therefore will need to be treated aggressively with antiepileptic medications. We present a prospective observational study of ten consecutive non-anoxic patients with PLEDs based on continuous 24-hour EEG monitoring. According to the EEG, five of the patients had seizures associated with PLEDs and five had PLEDs but no seizures. The aetiology included: neoplasm (n=1), cortical dysplasia (n=1), acute head trauma (n=1), encephalomalacia related to healed abscess (n=1), intra-parenchymal haemorrhage (n=1), and no structural lesion (n=5). All patients underwent brain MRI using diffusion-weighted imaging (DWI). We found that the five patients who had seizures with PLEDs on continuous EEG had restricted diffusion on DWI. In contrast, the five patients who had PLEDs but no seizures on continuous EEG did not show a restricted diffusion pattern on DWI. We will continue to prospectively assess DWI findings in this group of patients and encourage other centres to also review similar data. If our observation is replicated, this would indicate that restricted diffusion on brain MRI may be a useful marker to identify patients with PLEDs on their EEG who are likely to have associated seizures.
Keywords: DWI; EEG; PLEDs; diffusion-weighted imaging; periodic lateralized epileptiform discharges.