Figure 5.

(A) Typical interictal electroencephalographic background activity in a 39-year-old patient exhibiting bursts of sharply contoured theta activity, with a peak frequency of 5 Hz, over the temporal regions. (B) Ictal EEG from a 26-year-old woman with ring (20) syndrome. Repetitive spikes occurred in both frontal regions, followed by 3–4-Hz slow waves and spike-and-wave complexes. Spike-and-wave complexes gradually lost the spike component with increasing frequency and became polymorphous. The NCSE episode lasted 40 min, and the breaks between these recordings are at seizure onset, after 10 min, 20 min, and at the end of the seizure, when she fell asleep. Her verbal response was impaired and slow. Complex mental action such as calculation was impossible.