Verbal memory decline is less frequent at 10 years than at 2 years after temporal lobe surgery for epilepsy

Abstract

We investigated individual short- and long-term verbal memory changes after temporal lobe resection for epilepsy. Fifty-one patients (23 operated on the speech-dominant temporal lobe, DTL and 28 on the non-dominant temporal lobe, NDTL) were tested on learning/immediate recall and delayed recall of word-list and word-pairs preoperatively, 2years postoperatively and 10years postoperatively. Changes were defined using reliable change indices of 23 healthy controls assessed at corresponding intervals. Fewer patients had reliable declines at 10years than at 2years (DTL: 13–35% vs 35–44%; NDTL: 0–4% vs 7–21%). Four DTL patients (17%) had reliable declines in ≥2 tests at 10-year follow-up. More NDTL patients had improvement at 10years than at 2years (18–30% vs 4–22%). The only risk factor for decline both short and long term was DTL resection. In conclusion, most patients had stable verbal memory postoperatively. A few DTL patients had a lasting decline at long-term follow-up, but more patients showed partial recovery, especially in the NDTL group.