Expanding the spectrum of cognitive outcomes after temporal lobe epilepsy surgery: A prospective study of theory of mind.

OBJECTIVE

Because temporal lobe epilepsy (TLE) can impair theory of mind (ToM), we examined the effects of anterior temporal lobectomy (ATL) by comparing the preoperative to postoperative ToM course with that of other cognitive functions characteristically impaired in TLE.

METHODS

Eighty-five patients with left (n = 39) or right (n = 46) drug-resistant TLE and an age at epilepsy onset of >12 (n = 54) or ≤12 years (n = 31) were evaluated before and 1 year after surgery; 40 healthy controls were assessed at baseline. The participants' recognition and comprehension of faux pas (FPs) or correct rejection of nonexistent FPs was assessed using the Faux Pas task; and their language, memory, and planning were, respectively, assessed using the Boston Naming, Short Story, and Tower of London tests.

RESULTS

Baseline ToM was impaired in the patients with left or right TLE in comparison with the controls, and significantly influenced by education and age at seizure onset, with more severe deficits being observed in those with less education and an age at onset of ≤12 years. After ATL, their recognition and comprehension of FPs was unchanged, whereas the rejection of nonexistent FPs improved in the patients with early seizure onset. Education, preoperative ToM, postoperative executive function, and fluid intelligence and the number of antiepileptic drugs predicted postoperative ToM. Postoperative naming and episodic memory were associated with ATL laterality and education, and planning was associated with age at seizure onset and chronological age.

SIGNIFICANCE

After ATL, the components of ToM may be unchanged or slightly improved depending on cognitive reserve and age at seizure onset, thus suggesting that ATL does not further aggravate the deficits caused by TLE. Moreover, the course of ToM is distinct from that of other cognitive functions. These findings expand the spectrum of the cognitive phenotypes associated with TLE and ATL, and offer potential elements for individual prognoses.