Time Perception in Mesial Temporal Lobe Epilepsy Patients

Objectives: The present study investigates the explicit and implicit timing abilities of patients with mesial temporal lobe epilepsy (MTLE). Based on previous studies, it was hypothesized that timing abilities were decreased in MTLE patients. Methods: The performance of 21 MTLE patients and 20 neurologically healthy probands was tested on two separate tasks. The time bisection task was used to investigate explicit timing and the foreperiod task to test implicit timing. Results: For the time bisection task, a flatter psychophysical curve, indicative of less precise temporal judgements, was found in the patients compared to controls (RR = 0.64, 95% CI [0.57, 0.72], p = <.001). Also, patients with a higher IQ demonstrated less precise temporal judgments than patients with a lower IQ (RR = 0.76, 95% CI [0.67, 0.86], p = <.001). Moreover, the Weber Ratio (WR) of the patient group was higher than the control group’s WR (patient’s WR = 0.44, SD = 0.22; control’s WR = 0.31, SD = 0.14), indicating a significantly lower temporal sensitivity in the patient group (t(37) = -2.24, p = .031). In the foreperiod task, the RTs of the participants became shorter with longer durations which demonstrated the foreperiod effect (F(10,4992)= -0.19, p = <0.001). There was no statistical difference between the performance of the control and the patient group in the implicit timing task. Conclusions: MTLE patients showed less precise temporal judgments in explicit timing, while their implicit timing was largely preserved. This finding suggests that explicit time perception should be routinely investigated in MTLE patients.