Abstracts

Rationale:
A 1983 10-year prospective follow-up study of absence epilepsy at our institution found that 52% of 83 patients had persisting ABS, but follow-up was relatively brief and the population young. We sought to provide an additional 40 years of follow-up on this population to determine the very long-term seizure control and outcome.

Methods:
The patient data from the previous study was available in paper chart format. From prior study materials, we extracted whether patients had seizures controlled at the end of the prior study period, the number of medications they were on and the last date of follow-up at the end of that study period. Additional medical record review was performed to determine the patient's most recent clinic visit, whether their seizures were controlled at that visit, whether this was a change from prior status, and whether there were changes in their medication regimen.

Results:
A total of 56 of the original 83 subjects were identified from the original study. Of these 56 patients, 27 had data available from chart review, while the remainder were lost to follow-up. Average follow-up time for these patients between the end of the prior study and the most recent visit was 32 years. Of these 27 patients, 12 (44%) had seizures previously controlled and 15 (56%) had ongoing seizures at the time of the initial study. Of the 12 patients who had seizure control after the initial study, 11 (92%) of them continued to have good seizure control at later follow-up. Of the 15 patients who had poorly controlled absence seizures, nine (60%) of them later went on to develop seizure remission. On review of most recent data overall, 20 patients (74%) had seizures controlled and seven (26%) had ongoing seizures. Of the 20 patients who had seizure control at the recent visit, 11 of them (55%) had their seizures previously controlled at the end of the prior study period, while nine of them (45%) had new seizure control in the interim. Of the patients who had ongoing seizures, six (86%) had previously had ongoing seizures at the end of the prior study period and one (14%) had previously had seizure control but had seizure recurrence in the interim. In the interim overall, five patients (19%) had additional anti-seizure medications added to their regimen, while eight patients (30%) had their medications reduced or stopped.

Conclusions:
This study suggests that absence seizures will tend to stay controlled once they are controlled and often enter remission later. This study is limited in technical power due to the small sample size and the large percentage of patients lost to follow-up, but absence seizures tend to resolve even across decades of follow-up.

Funding: None