Serial cognitive change patterns across time after temporal lobe resection for epilepsy

Longitudinal cognitive outcome with respect to general cognitive status and memory at the group and individual levels was studied 10 years after temporal lobe resection for epilepsy. Twenty-five patients who had undergone a medium-term follow-up (T2, median = 2.7 years) also underwent a long-term follow-up (T3, median = 9.8 years). At the group level, there was a significant increment across time, partly due to practice, in IQ (P value from 0.049 to <0.0001) but not in memory variables. On the basis of the normative interval of reassessed matched controls, the analysis at the individual level of change from baseline to T2 disclosed decrements in 12–29% of the patients and increments in 8–21%. These proportions diminished at T3 (0–12 and 0–16%) and the dominating pattern of Performance IQ and verbal memory was a return toward baseline. These findings make the interpretation of an initial (T2) postoperative increment or decrement more problematic and underline the need for a comprehensive evaluation across time, including both at the group and individual levels.