Cognitive outcomes more than 5 years after temporal lobe epilepsy surgery: Remarkable functional recovery when seizures are controlled.

PURPOSE

Epilepsy surgery can be a successful treatment option for temporal lobe epilepsy but there are concerns about accelerated memory decline in long-term follow-up.

METHOD

161 adult operated (77 right, 84 left temporal resections) versus a heterogeneous group of 208 non-operated patients with focal epilepsies were consecutively recruited and re-evaluated focusing on memory, executive functions, and vocational outcome after follow-up intervals of >5 years (5-22 years, mean 8 ± 3 years).

RESULTS

Major losses in the operated group manifest early, at one-year follow-up. Few patients declined further. Long-term changes after surgery did not differ from those observed without surgery. The factor "surgery" caused verbal memory decline, "seizure freedom" (operated 48%, non-operated 17%) was associated with recovery of verbal memory, and "drug reduction" positively affected the course of executive functions. In terms of the critical function of verbal memory, only 3-17% of seizure-free patients showed long-term decline whereas 16-20% showed improvement (operated and non-operated). Persistent seizures were associated with decline in 12-37% and improvement in 4-12% of patients. Improvement was related to longer retest intervals and was stronger in younger patients. Independent of surgery or seizure outcome, the vocational status remained unchanged or change was negative (22%) rather than positive (3%).

CONCLUSIONS

Patients' cognitive course 5-22 years after surgery is stable and may even be positive if epilepsy is controlled and drug load reduced. Depending on seizure outcome, recovery is more frequently observed than continuing decline. Recovery, however, takes time and age is a limiting factor.