Accelerated long‐term forgetting in focal epilepsy: Do interictal spikes during sleep matter?

Lambert, Isabelle; Tramoni-Negre, E; Lagarde, Stanislas; Pizzo, Francesca; Fonseca, Agnès Trébuchon-Da; Bartolomei, Fabricē; Félician, Olivier

doi:10.1111/epi.16823

Cited by 20 publications

(17 citation statements)

References 86 publications

(155 reference statements)

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“…Preeminent hypotheses to explain memory complaint in the epileptic population have been (1) the influence of depressive mood, psychological distress, and disturbance of attentional functions 37 ; (2) the interference of medication on memory processes 38 ; and (3) the role of IEDs, especially during sleep. 39,40 The first and second hypotheses lack evidence or are supported by inconsistent or scarce results. 41 Our results do not corroborate these 2 hypotheses.…”

Section: Discussionmentioning

confidence: 99%

Hidden Objective Memory Deficits Behind Subjective Memory Complaints in Patients With Temporal Lobe Epilepsy

et al. 2022

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Objective:To test the hypothesis that temporal lobe epilepsy (TLE) patients with subjective initial memory complaints (not confirmed by an objective standard assessment) and various phenotypes also show objective very long-term memory deficit with accelerated long-term forgetting. We tested TLE patients with two surprise memory tests after three weeks: the standard Free and Cued Selective Reminding Test (FCSRT), and Epireal, a new test specifically designed to capture more ecological aspects of autobiographical memory.Methods:47 TLE patients (12 hippocampal sclerosis, 12 amygdala enlargement, 11 extensive lesions, 12 normal MRI) who complained about their memory, but for whom the standard neuropsychological assessment did not reveal any memory impairment after a standard delay of 20 minutes, underwent two surprise memory tests after three weeks. They were compared to 35 healthy control subjects.Results:After three weeks, FCSRT and Epireal recall scores were significantly lower in patients than in controls (p<0.001). There was no significant correlation between FCSRT and Epireal scores (p=0.99). Seventy-six percent of TLE patients had objective impairment on at least one of these very long-term memory tests, regardless of the existence and type of lesion or response to antiseizure medication. Easily applicable, Epireal had a higher effect size, detected deficits in 28% more patients, and is a useful addition to the standard workup.Conclusion:Assessing long-term memory should be broadened to a wide spectrum of TLE patients with a memory complaint, regardless of the epileptic syndrome, whether or not associated with a lesion. This could lead to rethinking TLE nosology associated with memory.

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Section: Discussionmentioning

confidence: 99%

Hidden Objective Memory Deficits Behind Subjective Memory Complaints in Patients With Temporal Lobe Epilepsy

et al. 2022

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“…However, there is now clear evidence in animals and humans that IEDs can result in cognitive impairment, especially if they are frequent and occur during important periods of brain development [23]. It is also widely accepted that sleep is relevant for memory consolidation and other cognitive processes [18,24] and that IEDs during sleep and sleep disruption in patients with epilepsy have a negative impact on cognitive functioning [19,25]. As for other newly developed ASMs, previous studies of cannabidiol treatment in epilepsy therapy also focused on seizure outcomes.…”

Section: Discussionmentioning

confidence: 99%

Effect of Cannabidiol on Interictal Epileptiform Activity and Sleep Architecture in Children with Intractable Epilepsy: A Prospective Open-Label Study

et al. 2021

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Background Cannabidiol has been shown to be effective in seizure reduction in patients with Dravet syndrome, Lennox-Gastaut syndrome, and tuberous sclerosis. However, very little is known about its potential to reduce interictal epileptiform activity and improve sleep architecture. Objective The objective of this prospective study was to evaluate the influence of cannabidiol therapy on the frequency of interictal epileptiform discharges (IEDs) and sleep microstructure in a cohort of children with drug-resistant epilepsy. Methods Children with drug-resistant epilepsy were prospectively followed from November 2019 to January 2021 during an open-label trial of cannabidiol at a dose of 20 mg/kg/day (to a maximum of 50 mg/kg/day) and stable concomitant medication. Electroencephalograms were recorded at baseline (T0) and after 3 months (T1). Two independent raters, blinded to clinical outcome, evaluated 5-min segments of sleep stage 2 or low-noise awake state. IEDs were visually identified and rates per minute calculated. Sleep microstructure was considered improved if sleep structures were seen at T1 that were not present at T0. IED rates at T0 and T1 were compared and correlated with seizure outcome, cannabidiol dose, initial IED rate, and disease duration. Results In total, 35 children (mean ± standard deviation age 10.1 ± 0.86) were included. The IED rate at T1 was significantly lower than at T0 (19.6 ± 19.5 vs. 36.8 ± 27.2, respectively; p < 0.0001). We found a moderate correlation between IED reduction and percentage of seizure reduction compared with baseline (Pearson's r = 0.39; p = 0.02), a moderate negative correlation between IED reduction and IED rate at T0 (r = − 0.34; p = 0.04), and a trend towards a moderate negative correlation between IED reduction and disease duration (r = − 0.32; p = 0.06). Sleep was recorded in 23 patients. Sleep microstructure was initially abnormal in 56.5% of sleep recordings and improved in 84.6% of those cases. Conclusion Our results strongly suggest the utility of cannabidiol in reducing IEDs and improving sleep microstructure in children with drug-resistant epilepsy. Larger controlled studies are needed to evaluate the clinical relevance of this effect in different epilepsy types.

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“…Studies have shown that IISs disrupt memory and cognition in both animal models [32] and epileptic patients [33] . Recent studies indicate that this is possibly due to intrahippocampal IISs disrupting memory consolidation during sleep involving the hippocampal and cortical circuits [34] , [35] . Those results suggest that IISs could be “hijacking” and disturbing normal memory processes [36] , [37] .…”

Section: Seizure Related Consolidation and Memory Related Changes Dur...mentioning

confidence: 99%

Epileptic seizures and link to memory processes

Das

Luczak

2022

AIMSN

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<abstract> <p>Epileptogenesis is a complex and not well understood phenomenon. Here, we explore the hypothesis that epileptogenesis could be “hijacking” normal memory processes, and how this hypothesis may provide new directions for epilepsy treatment. First, we review similarities between the hypersynchronous circuits observed in epilepsy and memory consolidation processes involved in strengthening neuronal connections. Next, we describe the kindling model of seizures and its relation to long-term potentiation model of synaptic plasticity. We also examine how the strengthening of epileptic circuits is facilitated during the physiological slow wave sleep, similarly as episodic memories. Furthermore, we present studies showing that specific memories can directly trigger reflex seizures. The neuronal hypersynchrony in early stages of Alzheimer's disease, and the use of anti-epileptic drugs to improve the cognitive symptoms in this disease also suggests a connection between memory systems and epilepsy. Given the commonalities between memory processes and epilepsy, we propose that therapies for memory disorders might provide new avenues for treatment of epileptic patients.</p> </abstract>

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Accelerated long‐term forgetting in focal epilepsy: Do interictal spikes during sleep matter?

Cited by 20 publications

References 86 publications

Hidden Objective Memory Deficits Behind Subjective Memory Complaints in Patients With Temporal Lobe Epilepsy

Hidden Objective Memory Deficits Behind Subjective Memory Complaints in Patients With Temporal Lobe Epilepsy

Effect of Cannabidiol on Interictal Epileptiform Activity and Sleep Architecture in Children with Intractable Epilepsy: A Prospective Open-Label Study

Epileptic seizures and link to memory processes

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