Six-Hz spike-and-wave bursts

Six-Hz spike-and-wave bursts ("Phantom spike and wave"; see arrows): three 1 second bursts from one routine EEG recording. (A) This pattern is accentuated in an average referential montage, sensitivity 5 uV/mm. Note the low amplitude, occipitally predominant "phantom" spikes (arrows), and the frequency of approximately 6 per second (B) in a longitudinal bipolar montage (7 uv/mm), this pattern is not as well-appreciated. This is a normal variant.