Paroxysmal fast activity: Does this EEG pattern occur only in Lennox-Gastaut syndrome?

Background: Paroxysmal fast activity (PFA) is defined by fast paroxysmal events in the electroencephalogram (EEG), usually associated with Lennox-Gastaut syndrome (LGS). Our aims were to verify the frequency of LGS and non-LGS in EEGs with PFA; and to correlate the EEG features (spatial distribution, frequency, amplitude and duration) between the two clinical groups. Methods: We analyzed 38 EEG tracings with PFA from 38 patients. We evaluated the spatial distribution, frequency, amplitude and duration of fast paroxysms. The two clinical groups (LGS and non-LGS) were statistically compared relative to the EEG data. Results: With regard to epileptic syndromes, 23 patients (60%) were classified as LGS and 15 patients (40%) as non-LGS. Concerning spatial distribution, our results showed that 86.8% of the examinations showed symmetrical PFA and 13.2% showed asymmetrical PFA. The statistical analysis did not show any difference between the two groups regarding the EEG spatial distribution or other EEG data. Conclusions: PFA can occur in other epileptic syndromes apart from LGS. The EEG features did not offer any distinction between the two clinical groups. The PFA is not a specific EEG marker of LGS.