Purpose: In contrast to EEG, which has guidelines for interpretation and a plethora of textbooks, the full range of activity seen in magnetoencephalography (MEG) has not been fleshed out. Currently, magnetoencephalographers apply criteria for EEG waveforms to MEG signals based on an assumption that MEG activity should have morphology that is similar to EEG. The purpose of this article was to show the characteristic MEG profile of positive occipital sharp transients of sleep.
Methods: Simultaneous MEG-EEG recordings of two cases are shown.
Results: In both the cases, the morphologic features of positive occipital sharp transients of sleep in MEG vary and sometimes mimic epileptic spikes.
Conclusion: This report raises a caution that a normal variant may have an even more epileptic appearance on MEG than on EEG. Using the simultaneously recorded EEG to avoid misinterpretation of spikey-looking positive occipital sharp transients of sleep in MEG is a natural and prudent practice.