Sleep and Rehearsal-Driven Memory in Epilepsy

Condition(s) studied

Investigational drug(s) / intervention(s)

Cognitive memory task on a computer: Encoding: (1) Participants will learn 60 associations between pairs of items (cue and target) that are presented sequentially at unique locations on a screen, in a given context. 30 pairs are presented once, and 30 pairs are presented repeatedly (4 times). (2) After learning, the first recall phase begins after a short delay of 30 minutes: 50% of the pairs are tested in a similar way, this time with an assessment of contextual memory. (3) The remaining 50% of pairs are tested after a 12-hour delay, involving either a day awake (condition 1) or a night asleep (condition 2).

Eye tracking: Eye-tracking will be carried out during the task to ensure that participants are focused on the task (quantification of the number and duration of eye fixations in the area of interest corresponding to the target presentation)

Questionnaires on task-related fatigue: Questionnaire on task-related fatigue (Likert-scale) will be completed by participants between blocks of items during the task

Questionnaire on task difficulty: Questionnaires on task difficulty (Likert-scale) will be completed by participants at the end of the task

Karolinska scale: Participants' state of sleepiness will be assessed at the beginning of each stage (encoding, immediate recall, delayed recall) using the Karolinska sleepiness scale

Study summary

Memory consolidation transforms unstable memory traces into lasting representations, a process enhanced by both sleep and rehearsal during learning. Rehearsal is thought to accelerate consolidation by inducing memory reactivations that resemble those occurring during sleep. However, the respective mechanisms of sleep- and rehearsal-induced consolidation-and their potential interactions-remain poorly understood, especially in patients with temporal lobe epilepsy, where rehearsal might help compensate for memory deficits linked to hippocampal dysfunction, and where sleep may exacerbate epileptic activity. The CORESOM-EPI study aims to compare the effects of rehearsal and sleep on memory consolidation in patients undergoing video-EEG monitoring. Participants will learn "object-place" associations under two conditions (single versus repeated encoding), with memory tested immediately and again after a 12-hour delay. This delay will either include a full day awake or a night of sleep, allowing direct comparison of sleep- and rehearsal-related consolidation effects. Each participant will perform the task twice, with "wake" and "sleep" condition, in a balanced order. As a preliminary phase of the CRIMES study (ANR-DFG 2024), CORESOM-EPI will help assess how sleep and rehearsal influence memory consolidation in epilepsy. It will also serve to adapt the behavioral task for clinical use, paving the way for a future intracranial EEG investigations that will explore the neural networks involved and their modulation by epileptic activity.

Eligibility

Primary outcome measure(s)

• Change in the percentage of object categories recalled (vs. not recalled) between immediate (30 min after learning) and delayed (12h after learning) recall for rehearsed versus non-rehearsed items. — Day 2
  The impact of rehearsal on object category recognition in an object-place learning paradigm is assessed. For the primary outcome, data from the 2 conditions ("wake" and "sleep" during the 12h period between immediate and delayed recall) will be pooled. Each participant will take part in the wake and sleep condition over 4 days (2 conditions separated by at least 24h), in a balanced order between participants.
• Change in the percentage of object categories recalled (vs. not recalled) between immediate (30 min after learning) and delayed (12h after learning) recall for rehearsed versus non-rehearsed items. — Day 2 + 12 hours
  The impact of rehearsal on object category recognition in an object-place learning paradigm is assessed. For the primary outcome, data from the 2 conditions ("wake" and "sleep" during the 12h period between immediate and delayed recall) will be pooled. Each participant will take part in the wake and sleep condition over 4 days (2 conditions separated by at least 24h), in a balanced order between participants.
• Change in the percentage of object categories recalled (vs. not recalled) between immediate (30 min after learning) and delayed (12h after learning) recall for rehearsed versus non-rehearsed items. — Day 2 + 36 hours
  The impact of rehearsal on object category recognition in an object-place learning paradigm is assessed. For the primary outcome, data from the 2 conditions ("wake" and "sleep" during the 12h period between immediate and delayed recall) will be pooled. Each participant will take part in the wake and sleep condition over 4 days (2 conditions separated by at least 24h), in a balanced order between participants.
• Change in the percentage of object categories recalled (vs. not recalled) between immediate (30 min after learning) and delayed (12h after learning) recall for rehearsed versus non-rehearsed items. — Day 2 + 48 hours
  The impact of rehearsal on object category recognition in an object-place learning paradigm is assessed. For the primary outcome, data from the 2 conditions ("wake" and "sleep" during the 12h period between immediate and delayed recall) will be pooled. Each participant will take part in the wake and sleep condition over 4 days (2 conditions separated by at least 24h), in a balanced order between participants.

Trial sites (1)

More Hospices Civils de Lyon trials in France

Other trials for the same condition