Memory Consolidation In Children Research Articles

Impaired declarative memory consolidation in children with REM sleep-related obstructive sleep apnea.

We explored whether declarative memory consolidation is impaired in children with rapid eye movement sleep-related obstructive sleep apnea (REM-OSA) and investigated the correlation between memory consolidation and sleep-related respiratory parameters. Participants were children with habitual snoring aged 6-14 years and control children. Participants underwent polysomnography and declarative memory testing. Participants with snoring were categorized as primary snoring (PS), non-rapid eye movement sleep-related obstructive sleep apnea (NREM-OSA), stage-independent (SI)-OSA, and REM-OSA according to obstructive apnea-hypopnea index (OAHI), OAHI in REM sleep (OAHIREM), and OAHI in NREM sleep (OAHINREM). Declarative memory consolidation level was assessed by recall and recognition rates. There were 34 controls and 228 children with sleep-disordered breathing: 73 PS, 48 NREM-OSA, 59 SI-OSA, and 48 REM-OSA. Total arousal index was lower in the REM-OSA group than in the NREM-OSA group. In all groups, retest scores were higher than immediate test scores. Recall consolidation in PS, SI-OSA, and REM-OSA groups was lower than for controls and lower in REM-OSA than in NREM-OSA. There were no correlations between recall consolidation or recognition consolidation and OAHI, OAHINREM, oxygen desaturation index in REM sleep, total arousal index, or REM sleep percent. Recognition consolidation was negatively correlated with OAHIREM. Memory consolidation is impaired in children with REM-OSA compared with NREM-OSA and controls. There was no significant correlation between memory consolidation and OAHI, and recognition consolidation was negatively correlated with OAHIREM. It is important to pay attention to the OSA subtype in children. Tang Y, Yang C, Wang C, Wu Y, Xu Z, Ni X. Impaired declarative memory consolidation in children with REM sleep-related obstructive sleep apnea. J Clin Sleep Med. 2024;20(3):417-425.

O005 Deficits in learning and overnight memory consolidation in children with mild sleep disordered breathing

Abstract Objectives Sleep disordered breathing (SDB) is associated with sleep fragmentation that can compromise daytime learning and impact overnight memory consolidation. Yet, research into learning and overnight memory consolidation of children with SDB is very limited. The objective of the current study is to determine if school aged children with SDB show deficits in learning and overnight consolidation of declarative and non-declarative memories compared to healthy control (HC) children. Methods This study included 50 school aged (7-16 years) children (25 SDB, 25 HC) of comparable sex, parental SES, and BMI. Parents completed the paediatric sleep questionnaire (PSQ) for all children. Children with SDB underwent an overnight sleep study. All children completed a cognitive battery, including assessment of IQ and memory. We employed two declarative memory tasks, one verbal and one visual, and one non-declarative memory task. We measured learning and recall at two delays (30 minutes and overnight) on memory tasks. Results On the visual declarative memory task children with SDB performed more poorly in learning, and recalled significantly fewer pictures following a night of sleep, compared to HC. On the non-declarative task learning of children with SDB and HC children was comparable but following a night of sleep accuracy improved less in the SDB group compared to the HC group. Discussion This study provides, to our knowledge for the first time, evidence of impairment of overnight declarative and non-declarative memory consolidation concurrently in school aged children with mild SDB, whose declarative (but not non-declarative) learning was also impaired.

Sleep Stage Transitions and Sleep-Dependent Memory Consolidation in Children with Narcolepsy-Cataplexy.

Electroencephalographic sleep stage transitions and altered first REM sleep period transitions have been identified as biomarkers of type 1 narcolepsy in adults, but not in children. Studies on memory complaints in narcolepsy have not yet investigated sleep-dependent memory consolidation. We aimed to explore stage transitions; more specifically altered REM sleep transition and its relationship with sleep-dependent memory consolidation in children with narcolepsy. Twenty-one children with narcolepsy-cataplexy and twenty-three healthy control children completed overnight polysomnography and sleep-dependent memory consolidation tests. Overnight transition rates (number of transitions per hour), global relative transition frequencies (number of transitions between a stage and all other stages/total number of transitions × 100), overnight transitions to REM sleep (transition from a given stage to REM/total REM transitions × 100), and altered first REM sleep period transitions (transitions from wake or N1 to the first REM period) were computed. Narcoleptic children had a significantly higher overnight transition rate with a higher global relative transition frequencies to wake. A lower sleep-dependent memory consolidation score found in children with narcolepsy was associated with a higher overnight transition frequency. As observed in narcoleptic adults, 90.48% of narcoleptic children exhibited an altered first REM sleep transition. As in adults, the altered sleep stage transition is also present in children with narcolepsy-cataplexy, and a higher transition rate could have an impact on sleep-dependent memory consolidation. These potential biomarkers could help diagnose type 1 narcolepsy in children more quickly; however, further studies with larger cohorts, including of those with type 2 narcolepsy and hypersomnia, are needed.

Offline Learning in Children: The Effect of Night Sleep and Wakefulness on Memory Consolidation of a Complex Motor Task

Background and Aims Sleep after a new sequence memory training can enhance the explicit memory in children. However, children’s sleep-dependent motor memory consolidation particularly in implicit complex sequence tasks is unclear. Therefore, this study aims to investigate the role of night-time sleep and wakefulness on children’s motor memory consolidation following an implicit complex task. Methods In the current study, 26 boys aged 9-12 years were randomly assigned in two groups of sleep and awake. Acquisition phase included 10 blocks of 96 trials. The sleep group performed initial training at 8 (±1) PM while the awake group performed it at 8 (±1) AM by using the dynamic arm movement task. The participants were not aware of the sequence order. After training, the children’s performance was tested after 12 hours. Results The results of 2×2 Mixed ANOVA in the consolidation phase showed the significant main effect of block on response time (P=0.000) and prediction error (P=0.023). However, the interaction effect of block and group were not significant on response time (P=0.566) and prediction error (P=0.887). Conclusion The sequence memory consolidation in children under an implicit complex task can be improved offline regardless of having sleep between training and test sessions. Hence, sleep is not necessary for offline enhancement of motor sequence skills. Passage of time is effective for improvement in dynamic arm movement task. Therefore, the role of sleep in offline learning of motor skills depends on the nature of the task used in training.

Motor memory consolidation in children: The role of awareness and sleep on offline general and sequence-specific learning

Abstract Study aim: The purpose of this study was to investigate the role of sleep and awareness on consolidation of general and Sequence-Specific learning in children. Material and methods: Male participants (n = 48, 10 to 12 years old) were assigned to one of four groups based on awareness and sleep. Acquisition phase took place in the morning (wake groups, 8 ± am) or in the evening (sleep groups, 8 ± pm) followed by a 12 hours retention interval and a subsequent delayed retention test (1 week). Children in the explicit groups were informed about the presence of the sequence, while in the implicit groups were not informed about it. For data analysis in consolidation of general sequence learning and Sequence-Specific Consolidation phases, 2 × 2 × 2 and 2 × 2 × 3 ANOVA with repeated measures on block tests were used respectively. Results: The data provides evidence of offline enhancement of general motor learning after 12 hours which was dependent on sleep and awareness. Moreover, the information persistence after 1-week was significant only in sleep groups. The results also indicated that consolidation of sequence-specific learning was only observed after 12 hours in element duration and it was related to sleep and awareness. Conclusions: The results revealed that sleep wasn’t only an essential factor in enhancement of off-line sequence learning task after 12 hours in children, but performance of the children was dependent on awareness and sleep.

The Prominence of Self-referential Processing across ERP and Memory Consolidation in Children

ABSTRACT We examined behavioral and electrophysiological indices of self-referential and valence processing during a Self-Referential Encoding Task in 9- to 12-year-old children, followed by surprise memory tasks for self- and other-referential trait adjectives. Participants endorsed more positive than negative self-referential information but equally endorsed positive and negative information about the other character. Children demonstrated enhanced parietal LPP amplitudes in response to self- compared to other-referential trait adjectives. Positive and negative information was differentially remembered depending on the order of the referent cues presented, suggesting that social information undergoes differential consolidation processes depending on the referent and the order of presentation.

Alterations of procedural memory consolidation in children with developmental dyslexia. Correction to Hedenius et al. (2020).

Reports an error in "Alterations of procedural memory consolidation in children with developmental dyslexia" by Martina Hedenius, Jarrad A. G. Lum and Sven Bölte (Neuropsychology, Advanced Online Publication, Nov 19, 2020, np). In the article, three corrections have been made. The university affiliation for Martina Hedenius was listed incorrectly and should have read Uppsala University. The figures have been rearranged so that they appear in two-column format. In the Results section, the heading "Overnight Consolidation of Sequence Specific Knowledge" has been changed to "Consolidation of Sequence Specific Knowledge." All versions of this article have been corrected. (The following abstract of the original article appeared in record 2020-86309-001.) Objective: The objective of the present study was to determine if consolidation of procedural memory in developmental dyslexia (DD) may be supported by prolonging the initial learning session. Method: Children with DD (n = 31) and typically developing (TD) children (n = 34) were given a procedural (implicit sequence) learning task over two sessions, separated by a 24-hr interval. Session 1 was prolonged with 50% compared with previous studies of procedural memory consolidation in DD. Results: The amount of sequence learning was similar in the two groups at the end of Session 1 (p = .797, ηρ² = .001). At the follow-up session after 24 hr, performance in the DD group was poorer compared with the TD group (p = .003, ηρ² = .129). The amount of sequence knowledge in Session 2 predicted unique variance in reading fluency (p = .024, ηρ² = 0.083), independent of children's phoneme awareness and inattention symptoms. Conclusion: The present study shows that consolidation of procedural memory is impaired in DD, even when the initial learning session is prolonged. The findings encourage further research on the mechanisms supporting procedural memory consolidation in children with DD, and how these may be strengthened. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Alterations of procedural memory consolidation in children with developmental dyslexia.

[Correction Notice: An Erratum for this article was reported in Vol 35(2) of Neuropsychology (see record 2021-29488-002). In the article "Alterations of Procedural Memory Consolidation in Children With Developmental Dyslexia," by Martina Hedenius, Jarrad A. G. Lum, and Sven Bölte (Neuropsychology, 2021, Vol. 35, No. 2, pp. 185-196, https://doi.org/10.1037/neu0000708), three corrections have been made. The university affiliation for Martina Hedenius was listed incorrectly and should have read Uppsala University. The figures have been rearranged so that they appear in two-column format. In the Results section, the heading "Overnight Consolidation of Sequence Specific Knowledge" has been changed to "Consolidation of Sequence Specific Knowledge." All versions of this article have been corrected.] Objective: The objective of the present study was to determine if consolidation of procedural memory in developmental dyslexia (DD) may be supported by prolonging the initial learning session. Method: Children with DD (n = 31) and typically developing (TD) children (n = 34) were given a procedural (implicit sequence) learning task over two sessions, separated by a 24-hr interval. Session 1 was prolonged with 50% compared with previous studies of procedural memory consolidation in DD. Results: The amount of sequence learning was similar in the two groups at the end of Session 1 (p = .797, ηρ² = .001). At the follow-up session after 24 hr, performance in the DD group was poorer compared with the TD group (p = .003, ηρ² = .129). The amount of sequence knowledge in Session 2 predicted unique variance in reading fluency (p = .024, ηρ² = 0.083), independent of children's phoneme awareness and inattention symptoms. Conclusion: The present study shows that consolidation of procedural memory is impaired in DD, even when the initial learning session is prolonged. The findings encourage further research on the mechanisms supporting procedural memory consolidation in children with DD, and how these may be strengthened. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Sleep-Related Declarative Memory Consolidation in Children and Adolescents with Developmental Dyslexia.

Sleep has a crucial role in memory processes, and maturational changes in sleep electrophysiology are involved in cognitive development. Albeit both sleep and memory alterations have been observed in Developmental Dyslexia (DD), their relation in this population has been scarcely investigated, particularly concerning topographical aspects. The study aimed to compare sleep topography and associated sleep-related declarative memory consolidation in participants with DD and normal readers (NR). Eleven participants with DD and 18 NR (9–14 years old) underwent a whole-night polysomnography. They were administered a word pair task before and after sleep to assess for declarative memory consolidation. Memory performance and sleep features (macro and microstructural) were compared between the groups, and the intercorrelations between consolidation rate and sleep measures were assessed. DD showed a deeper worsening in memory after sleep compared to NR and reduced slow spindles in occipito-parietal and left fronto-central areas. Our results suggest specific alterations in local sleep EEG (i.e., sleep spindles) and in sleep-dependent memory consolidation processes in DD. We highlight the importance of a topographical approach, which might shed light on potential alteration in regional cortical oscillation dynamics in DD. The latter might represent a target for therapeutic interventions aimed at enhancing cognitive functioning in DD.

Exploration of a novel virtual environment improves memory consolidation in ADHD

Experimental evidence in rodents and humans suggests that long-term memory consolidation can be enhanced by the exploration of a novel environment presented during a vulnerable early phase of consolidation. This memory enhancing effect (behavioral tagging) is caused by dopaminergic and noradrenergic neuromodulation of hippocampal plasticity processes. In translation from animal to human research, we investigated whether behavioral tagging with novelty can be used to tackle memory problems observed in children and adolescents with attention-deficit/hyperactivity disorder (ADHD). 34 patients with ADHD and 34 typically developing participants (age 9–15 years) explored either a previously familiarized or a novel virtual environment 45 min after they had learned a list of 20 words. Participants took a free recall test both immediately after learning the word list and after 24 h. Patients who explored a familiar environment showed significantly impaired memory consolidation compared to typically developing peers. Exploration of a novel environment led to significantly better memory consolidation in children and adolescents with ADHD. However, we did not observe a beneficial effect of novel environment exploration in typically developing participants. Our data rather suggested that increased exploration of a novel environment as well as higher feelings of virtual immersion compromised memory performance in typically developing children and adolescents, which was not the case for patients with ADHD. We propose that behavioral tagging with novel virtual environments is a promising candidate to overcome ADHD related memory problems. Moreover, the discrepancy between children and adolescents with and without ADHD suggests that behavioral tagging might only be able to improve memory consolidation for weakly encoded information.

Sleep-dependent memory consolidation in children with self-limited focal epilepsies

ObjectiveChildren with self-limited focal epilepsies of childhood (SLFE) are known to show impaired memory functions, particularly in the verbal domain. Interictal epileptiform discharges (IED) in these epilepsies are more pronounced in nonrapid eye movement (NREM) sleep. Nonrapid eye movement sleep is crucial for consolidation of newly-encoded memories. Therefore, we hypothesize that sleep-dependent memory consolidation is altered in relation to IED in children with SLFE. MethodsWe conducted a prospective case–control study. We applied a verbal (word pair) and a visuospatial (two-dimensional [2D] object location) learning task, both previously shown to benefit from sleep in terms of memory consolidation. Learning took place in the evening, and retrieval was tested in the morning after a night of sleep. Electroencephalogram (EEG) was recorded across night. After sleep-stage scoring, the spike–wave index (SWI) was assessed at the beginning and the end of sleep. Fourteen patients with SLFE (age: 5.5 to 11.6 years) were compared with 15 healthy controls (age: 6.8 to 9.1 years) examined in a previous study. ResultsIn contrast to healthy controls (mean: +12.9% recalled word pairs, p = .003, standard deviation (SD) = 12.4%), patients did not show overnight performance gains in the verbal memory task (mean: +6.4% recalled word pairs, p > .05, SD = 17.3) Neither patients nor controls showed significant overnight changes in visuospatial task performance. Spike–wave index was negatively correlated with recall performance in the verbal but not in the visuospatial task. SignificanceWe found evidence for impaired overnight improvement of performance in children with SLFE in a verbal learning task, with high SWI rates predicting low recall performance. We speculate that spike–waves hamper long-term memory consolidation by interfering with NREM sleep.

The power of children\u2019s sleep - Improved declarative memory consolidation in children compared with adults

Post-learning slow wave sleep (SWS) is known to support declarative memory consolidation. As SWS is more abundant in young population, we suggested that sleep-dependent memory consolidation processes could occur at a faster pace in school-aged children. After learning new associations between non-objects and their functions, retrieval performance was tested in 30 children (7–12 years) and 34 adults (20–30 years) during an immediate (IR) and a delayed retrieval (DR) session separated by either a Sleep or a Wake condition. Sleep led to stabilized memory retrieval performance only in children, not in adults, whereas no age-related difference was observed after a similar period of wakefulness. Hence, our results suggest more efficient sleep-dependent declarative memory consolidation processes in children compared with adults, an effect potentially ascribed to more abundant and deeper SWS during childhood.

Sleep Related Memory Consolidation in Children With Age Related Focal Epilepsy.

Sleep Related Memory Consolidation in Children With Age Related Focal Epilepsy.

0747 Impaired Memory Consolidation in Children with Obstructive Sleep Disordered Breathing

0747 Impaired Memory Consolidation in Children with Obstructive Sleep Disordered Breathing

NREM sleep spindles predict impaired memory consolidation in children with OSA (S17.006)

NREM sleep spindles predict impaired memory consolidation in children with OSA (S17.006)

Impaired memory consolidation in children with obstructive sleep disordered breathing.

Memory consolidation is stabilized and even enhanced by sleep (and particularly by 12–15 Hz sleep spindles in NREM stage 2 sleep) in healthy children but it is unclear what happens to these processes when sleep is disturbed by obstructive sleep disordered breathing. This cross-sectional study investigates differences in declarative memory consolidation among children with primary snoring (PS) and obstructive sleep apnea (OSA) compared to controls. We further investigate whether memory consolidation group differences are associated with NREM stage 2 (N2) sigma (12–15 Hz) or NREM slow oscillation (0.5–1 Hz) spectral power bands. In this study, we trained and tested participants on a spatial declarative memory task with cued recall. Retest occurred after a period of daytime wake (Wake) or a night of sleep (Sleep) with in-lab polysomnography. 36 participants ages 5–9 years completed the protocol: 14 with OSA as defined by respiratory disturbance index (RDI) > 1/hour, 12 with primary snoring (PS) and 10 controls. OSA participants had poorer overall memory consolidation than controls across Wake and Sleep conditions [OSA: mean = -18.7% (5.8), controls: mean = 1.9% (7.2), t = -2.20, P = 0.04]. In contrast, PS participants and controls had comparable memory consolidation across conditions (t = 0.41; P = 0.38). We did not detect a main effect for condition (Sleep, Wake) or group x condition interaction on memory consolidation. OSA participants had lower N2 sigma power than PS (P = 0.03) and controls (P = 0.004) and N2 sigma power inversely correlated with percentage of time snoring on the study night (r = -0.33, P<0.05). Across all participants, N2 sigma power modestly correlated with memory consolidation in both Sleep (r = 0.37, P = 0.03) and Wake conditions (r = 0.44, P = 0.009). Further observed variable path analysis showed that N2 sigma power mediated the relationship between group and mean memory consolidation across Sleep and Wake states [Bindirect = 6.76(3.5), z = 2.03, P = 0.04]. NREM slow oscillation power did not correlate with memory consolidation. All results retained significance after controlling for age and BMI. In sum, participants with mild OSA had impaired memory consolidation and results were mediated by N2 sigma power. These results suggest that N2 sigma power could serve as biomarker of risk for cognitive dysfunction in children with sleep disordered breathing.

An evening milk drink can affect word recall in Indonesian children with decreased sleep efficiency: A randomized controlled trial

Study objectives: Sleep is important for memory consolidation in children. This study intended to find out whether an evening milk-based drink could influence sleep efficiency and memory recall in a group of Indonesian children (5–6 years old) with sleep deprivation.Methods: Children were randomly allocated to one of three interventions: Reference product, satiety-stimulating product, and a relaxing product. The intervention lasted for 6 weeks and children consumed two servings per day of each 200 ml, the serving in the morning being the same for all children. All measurements took place at baseline and at the end of the intervention. Sleep parameters were studied using actigraphy and a sleep diary during three consecutive days. Memory consolidation was tested using a 20 word-pair list, which was memorized the evening before being recalled the next morning at home-base. Anthropometry was measured using standard equipment.Results: The Satiety group showed a significant decrease in word recall, and a significant increase in nocturnal awakenings that was inversely associated with sleep efficiency at the end of the intervention. Sleep efficiency did not differ between the three groups being 75.5 ± 8.6% and 75.7 ± 6.3% at baseline and end of the intervention, respectively. Despite the lower energy intake in the Standard (reference) group, this condition showed the highest increase in weight.Discussion: Evening growing-up milks can affect memory recall, sleep characteristics, and growth. However, to correct sleep efficiency and sleep duration, improvement of parental behavior may be the most important factor with nutrition providing a supplementary effect.

Does sleep benefit memory consolidation in children with focal epilepsy?

Children with epilepsy have high rates of both cognitive impairment and sleep disruption. It is thus assumed that sleep-dependent memory consolidation is vulnerable to ongoing epileptic activity, but direct evidence of this is limited. We performed a within-subject comparison of memory retention across intervals of wake or overnight sleep. Healthy children (n = 21, 6-16 years, 12 female) and children with focal epilepsy (n = 22, 6-16 years, 9 female) performed verbal and visuospatial memory tasks under each condition. Sleep was assessed with electroencephalography (EEG) polysomnography during the overnight interval. Interictal discharges were quantified manually. Memory retention was greater in the sleep condition in both the verbal (F1,39 = 10.8, p = 0.002, Cohen's d = 0.67) and the visuospatial (F1,36 = 4.23, p = 0.05, Cohen's d = 0.40) tasks, with no significant interaction of group by condition in either task. Across the total sample, gain in memory retention with sleep in the verbal task correlated with duration of slow wave sleep (r = 0.4, p = 0.01). In patients, sleep-dependent memory consolidation was negatively correlated with interictal discharge rate in both the verbal (ρ = -0.49, p = 0.04) and visuospatial (ρ = -0.45, p = 0.08) tasks. On post hoc analysis, a longer history of epilepsy (r = 0.53, p = 0.01) and a temporal (t10 = 1.8, p = 0.1, Cohen's d = 0.86) rather than an extratemporal seizure focus (t10 = 0.8, p = 0.4, Cohen's d = 0.30) was associated with greater contribution of sleep to verbal memory retention. We have demonstrated that memory consolidation in children with focal epilepsy benefits from sleep, showing the same correlation with slow wave sleep as in healthy children, but an inverse relationship with the interictal discharge load during sleep. This mechanism appears to be increasingly recruited with longer duration of illness, indicating a resilient homeostatic function which may be harnessed to aid learning.

Memory consolidation in children with specific language impairment: Delayed gains and susceptibility to interference in implicit sequence learning

ABSTRACTIn this study, the time course of the procedural learning of a visuomotor sequence skill was followed over a 24-hour and a 1-week time period in children with and without specific language impairment (SLI). Two aspects of memory consolidation in implicit sequence learning were examined: the evolution of post-training gains in sequence knowledge (Experiment 1) and the susceptibility to interference (Experiment 2). In the first experiment, 18 children with SLI and 17 control children matched for sex, age, and nonverbal intelligence completed a serial reaction-time (SRT) task and were tested 24 hours and 1 week after practicing. The two groups of children attained an equal level of sequence knowledge in the training session, but the children with SLI lacked the consolidation gains displayed by the control children in the two post-training sessions. Working with a new group of children, 17 with SLI and 17 control peers, Experiment 2 examined resistance to interference by introducing a second sequence 15 min after the first training session. Similar results were obtained for the performance of both groups in the training session. However, although the performance of the control group improved in the post-training sessions, the performance of the SLI group deteriorated significantly during the consolidation phase due to the interfering sequence. These findings suggest that the consolidation phase of sequence learning is impaired in children with SLI.

Sleep architecture and memory consolidation in children with focal epilepsy

BackgroundCognitive impairment is a major comorbidity in children with epilepsy. During the past decade, evidence has emerged that the consolidation of declarative memory (memory for facts and events) is promoted by slow-wave sleep. The aim of this study was to investigate whether sleep architecture is disrupted in children with epilepsy, and whether this disruption impacts on memory consolidation in these children compared with healthy children. MethodsA within-subject comparison of memory retention across similar length intervals overnight (sleep condition) or daytime (wake condition) was performed in 20 children with focal epilepsy (aged 6–16 years) and 19 healthy, age-matched children (controls). For each condition, participants learned a list of semantically related word pairs for cued recall after the interval. Patients participated during admission for video electroencephalogram (EEG) telemetry, whereas controls underwent ambulatory EEG polysomnography across the sleep condition. FindingsChildren with epilepsy had less rapid eye movement sleep (ANCOVA with age as covariate F=8·2, p=0·007) and more stage 2 sleep (F=5·335, p=0·027) than did controls, but a similar amount of slow-wave sleep and stage 1 sleep. Memory retention was greater in the sleep than the wake condition (repeated measures ANOVA F=7·876, p=0·008) and there was no significant interaction effect with group (patients vs controls) or order of conditions. The difference in memory retention scores between the sleep and wake conditions correlated with the proportion of time that the child spent in slow-wave sleep across the total sample (Pearson r=0·461, p=0·003). This association was significant in controls (r=0·546, p=0·051), but did not reach significance in children with epilepsy, and was not altered after controlling for age. InterpretationPatients with focal epilepsy show benefit to memory consolidation with sleep similar to that seen in healthy individuals, despite the underlying disease and effects of treatment. The association with slow-wave sleep, which is preserved at the expense of rapid eye movement sleep, also seems robust. Our findings suggest that the enhancement of slow-wave sleep—by behavioural, pharmacological, or physical means—has the potential to improve cognitive outcome in this patient group. FundingAction Medical Research, Reta Lila Howard Foundation.