What are the EEG characteristics of the small sharp spikes (SSSs) epileptiform normal variant?

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

Small sharp spikes (SSSs), also known as benign epileptiform transients of sleep (BETS), occur in light sleep (stages I and II of nonrapid eye movement [NREM] sleep), usually sporadically. [12] Their location is temporal, either unilateral or bilaterally independent, and with a broad field of distribution. The morphology is typically monophasic, occasionally diphasic, and the decline after the first negative peak is very steep. SSSs rarely may have a single aftergoing slow-wave component but generally do not disturb the background.

The main features of SSSs are expressed in their name: their duration is short, and their amplitude is small. An easy guideline states that SSSs generally should last less than 50 milliseconds and should be smaller than 50 µV (see the images below). 

Small sharp spike is present in left temporal regi Small sharp spike is present in left temporal region (modified double banana montage). Note widespread field of distribution (isopotential at F7, T1, and T3), low amplitude (< 50 µV), and short duration (< 50 ms).
Left temporal small sharp spike. Note low amplitud Left temporal small sharp spike. Note low amplitude (< 50 µV) and short duration (< 50 ms).
Small sharp spike is present in right temporal reg Small sharp spike is present in right temporal region. Note low amplitude (< 50 µV) and short duration (< 50 ms).

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