Nighttime seizures disrupt sleep-dependent memory consolidation, according to a pilot study published in the journal Clinical Neurophysiology.This finding is important, because it will help scientists to better understand the effect of seizures on memory consolidation, and the factors that may influence this. There is currently only limited data in adults, and some conflicting data in children, regarding sleep dependent memory consolidation in epilepsy, although the association is not new.For the current study, a team led by Dr Ellen Bubrick, from Harvard Medical School, in Boston, recruited 11 people with focal epilepsy aged between 21 and 56 years.The researchers asked the subjects to complete a memory test, during which they were required to remember the positions of 15 pairs of coloured images of animals and everyday objects, on a 5 x 6 matrix. Participants were first shown where the object pairs were located (the ‘training’ stage), and then asked to remember this after either 12 hours of continuous wakefulness, or 12 hours that included sleep.The results showed that memory retention after 12 hours of wakefulness was 62.7%, but this increased to 83.6% when the 12-hour period included sleep. This suggests that sleep enhances memory consolidation in epilepsy.During the study, three of the participants had daytime seizures and three had nighttime seizures. The scientists found that the daytime seizures had no effect on memory, as assessed, but that nighttime seizures resulted in a drop in retention rates.Memory difficulties are commonly seen in people with epilepsy, and these can sometimes be more debilitating than the seizures themselves. If the effects of seizures on sleep-dependent memory seen here are confirmed in larger studies, it may be possible to develop ways of managing them in the future.Author: Dr Özge ÖzkayaClick here to read more stories about living with epilepsy.