The EEG profile of patients with uncontrolled vs. controlled seizures

The goal of this study was to provide an EEG profile of patients (150) with uncontrolled (U) seizures, in contrast with those (150) with controlled (C) attacks. In the U group 804 EEGs were done and in the C group 674 were performed, all with both waking and sleep recordings; the range of EEG records on a given patient was 2-23. The number of spikes and the amount of abnormal slowing was quantified in each record. Two different peaks of age were evident, appearing at 10-19 yrs and 40-49 yrs. The number of patients with a spike discharge on the first EEG was 64% in the C and 92% in the U group with an increasing incidence to 83% (C) and 100% (U) in later records. If spikes were absent in the first EEG in the C group, the majority showed only rare discharges later. The spike profile of the U patient initially was that 1/2 showed a typical number of spikes and nearly 1/2 many or very many spikes. Over time a decrease was seen in those with many-very many discharges, resulting in an increase with a typical number. Still later, a reversal occurred in the U patients with an increasing number with many or very many spikes. The slow wave profile of the U patient was that 2/3 showed some abnormal slow waves on the first record, increasing to 100% in later records. The increase was from delta, not theta activity. The spike profile of the C patient was that a typical number of spikes was seen at first in nearly 1/2, but only a small minority showed many-very many discharges. The slow wave profile for the C patient was that theta, not delta waves, increased in time. The (median) time between a unilateral spike discharge to a bilateral discharge was 4-5 yrs, and the U group much more often than the C group showed this change to bilateral spikes. The time between unilateral to bilateral slow waves varied between 4-9 yrs.