What are the characteristics of the 6-Hz phantom spike-wave epileptiform normal variant?

Updated: May 11, 2018
  • Author: Selim R Benbadis, MD; Chief Editor: Helmi L Lutsep, MD  more...
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Answer

Answer

The 6-Hz phantom spike-wave pattern may be observed in both adolescents and adults. It generally occurs during relaxed wakefulness and stage I sleep and disappears during deeper levels of sleep.

The frequency is 6 Hz, as the name indicates, and the bursts last 1-2 seconds. The location is usually diffuse, bisynchronous, and relatively symmetric. This pattern may predominate in the anterior and posterior head regions. The morphology typically consists of a small (< 30 µV and < 30 ms), evanescent diphasic spike followed by a higher (50-100 µV) slow wave component. Thus, the spike component may be difficult to see.


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