Explicit and implicit timing 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 21 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, less precise temporal judgements were found in the patient group compared to the control group. This was indicated by a flatter psychophysical curve in the patients compared to controls. Moreover, participants did not differ in term of precision, but patients were more variable than controls. There was no statistical difference between the performance of the control and the patient group in the implicit timing task. Both groups demonstrated the foreperiod effect, meaning that the RTs of the participants became shorter with longer durations. 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.