Intact information sampling in mesial temporal lobe epilepsy

Previous studies have reported deficits in decision making under ambiguity for patients with mesial temporal lobe epilepsy (mTLE). It is unknown whether mTLE is also associated with alterations at a predecisional stage. This study aimed to gain insight into predecisional processing of patients with mTLE.

We compared performance of patients with mTLE (n = 25) with that of healthy controls (n = 75) on the information sampling task (IST), a task assessing reflection-impulsivity and predecisional information sampling.

Patients and healthy controls showed a similar performance pattern in both conditions of the IST as indicated by the amount of information gathered, the degree of uncertainty tolerated, and the number of decision errors made. They both also demonstrated a significant sensitivity to the different reward characteristics of the task. For the patient group, we found no significant effects on performance on the IST of epilepsy lateralization, abnormality side, structural abnormality (hippocampus vs. amygdala), and medication (monotherapy vs. polytherapy).

Reflection processes and predecisional information sampling as tested by the IST are intact in mTLE. Patients collect as much information as healthy individuals and adapt their behavior according to the changing reward conditions. Our findings indicate that in well-defined risk situations, where memory demands are sufficiently minimized, patients with mTLE should be able to gather sufficient information, weight risks and benefits, and make advantageous decisions.