Spindles insufficiency in sleepwalkers' deep sleep.

OBJECTIVES: Sleepwalkers have consistently shown N3 sleep discontinuity, especially after sleep deprivation. In healthy subjects, sleep spindles activity has been positively correlated to sleep stability. We aimed to compare spindles density during N3 sleep between sleepwalkers and healthy controls. METHODS: Two cohorts of 10 and 21 adult sleepwalkers respectively controlled with 10 and 18 healthy volunteers underwent one baseline and one recovery sleep recording after 38h (cohort 1) and 25h (cohort 2) of sleep deprivation. For the two recordings, we performed an automatic detection of spindles (11-16Hz) from EEG signal during N3 sleep, restricted to the first sleep cycle and repeated for all cycles. For better interpretation of results, we extended the analysis to N2 sleep and we also measured the density of slow waves oscillation (SWO) (0.5-4Hz) during the same periods. RESULTS: Compared to controls, sleepwalkers showed significantly lower spindle densities during N3 sleep considering the first sleep cycle (both cohorts) or all cycles (cohort 1). SWO densities did not differ (cohort 1) or were lower (cohort 2) for sleepwalkers. The effect of sleep deprivation did not interact with the effect of group on spindles and SWO densities. CONCLUSION: This work suggests that the instability of N3 sleep inherent to sleepwalkers may be underpinned by a specific alteration of spindles activity.

Stereo-electroencephalography identifies N2 sleep and spindles in human hippocampus.

OBJECTIVES: To describe the hippocampal stereo-electroencephalogram during sleep according to sleep stages (including N2 sleep) and cycles, together with the hippocampal spindles. METHODS: All patients with drug-resistant focal epilepsy undergoing intra-hippocampal implantation between August 2012 and June 2013 at Nancy University Hospital were screened. Six patients with explored hippocampus devoid of pathological features were analyzed. During one night, we identified continuous periods of successive N2, N3 and REM sleep for two full cycles. We performed a spectral analysis of the hippocampal signal for each labeled sleep period. RESULTS: N2, N3 and REM sleeps were individualized according to their spectral powers, for each frequency band and sleep cycle. Hippocampal spindles showed dynamic intrinsic properties, the 11.5-16Hz frequency band being mainly dominant, whereas the 9-11.5Hz frequency band heightening during the beginning and the end of the transient. For N3 and REM sleep stages, the power of the hippocampal signal was significantly decreased between the first and the second sleep cycle. CONCLUSION: Distinct N2 sleep, fast spindles and homeostatic profile are all common properties shared by hippocampus and cortex during sleep. SIGNIFICANCE: The close functional link between hippocampus and cortex may have various sleep-related substrates.

[Adherence to medication and epilepsy: a current issue]. / Adhésion au traitement médicamenteux et épilepsie : un enjeu d'actualité

As in other chronic diseases, adherence to medication in epilepsy is critical for seizure control. Its assessment remains challenging in research as in clinical practice. Recent evidences showed another face of nonadherence: the overconsumption of antiepileptic drugs. Some educational interventions with easy implementation were found to be effective in improving adherence and should be therefore more used in everyday practice.

Direct evidence of nonadherence to antiepileptic medication in refractory focal epilepsy.

The adherence to medication in drug-resistant focal epilepsy (RFE) remains largely unknown. The present work aimed to assess the frequency of recent adherence to antiepileptic drugs (AEDs) in patients with RFE. This prospective observational study screened all patients with RFE, admitted to the Nancy University Hospital between April 2006 and September 2008, for a 5-day hospitalization without AED tapering. The adherence to AEDs was assessed by measuring serum drug levels on day 1 (reflecting the recent "at home" adherence) and day 5 (reflecting the individual reference concentration when drug ingestion was supervised). A patient was considered nonadherent if at least one of their serum drug levels was different between days 1 and 5. The day-1 value was considered different from day 5 when it was at least 30% lower (underdosed) or 30% higher (overdosed). Nonadherent patients were classified as under-consumers in the case of one or more underdosed day-1 values, over-consumers in the case of one or more overdosed day-1 values, or undefined if they exhibited both underdosed and overdosed day-1 values. Forty-four of the 48 screened patients were included. Eighteen (40.9%) of 44 patients were nonadherent. Among them, 12 (66.7%) were over-consumers, 4 (22.2%) were under-consumers, and 2 (11.1%) were undefined nonadherents. The study indicates that recent adherence to antiepileptic medication in this group of patients with RFE is poor. Overconsumption is the most frequent form of nonadherence in this population and should be specifically assessed to prevent its possible consequences in terms of AEDs dose-dependent adverse events.

Serial brain MRI in TIA patients.

OBJECTIVE: Up to 40% of patients with transient ischemic attack (TIA) demonstrate lesions on diffusion-weighted magnetic resonance imaging (DWI). However, the time course of these ischemic lesions is not well known. Some lesions could vanish soon after symptom onset whereas others could be visible only after a certain delay. Based on a population of TIA patients imaged twice with DWI within the first week after onset, our aim was to estimate the rate of patients with DWI reversible ischemic lesion or with delayed DWI positivity. METHODS: We retrospectively compared DWI at admission (DWI(1), median = 15 hours after TIA) with follow-up DWI (DWI(2), median = 47 hours) in 64 consecutive TIA over a 7-month period. DWI was reviewed in consensus by two readers, blinded to clinical information. Number, extent and arterial distribution of lesions were assessed. RESULTS: DWI(1) and DWI(2) showed similar findings in 55 TIA patients (32 with and 23 without ischemic lesions). In nine (14%) patients, changes were observed on DWI(2): presence of ischemic lesions despite normal DWI(1) (n = 3), increase in lesion size (n = 3), or partial or complete lesion reversibility (n = 3). CONCLUSION: In most TIA cases, ischemic lesions captured by early DWI and 48-hour DWI are similar. However, some ischemic lesions vanish rapidly while lesion visibility is delayed in other cases.