SAS CARE 1: Sleep architecture changes in a cohort of patients with Ischemic Stroke/TIA.

OBJECTIVE: Changes in sleep architecture following ischemic stroke have been poorly investigated. Our objective was to explore changes of sleep structure in patients with ischemic stroke or transient ischemic attack in order to verify a possible predictive value of sleep with respect to clinical outcome. METHODS: Patients recruited in the prospective SAS-CARE study received two polysomnographies (PSG) in the acute and chronic phases after stroke/TIA. Sleep parameters were compared between the two time-points and matched with a non-stroke population randomly selected from the HypnoLaus cohort. RESULTS: Of the 169 patients investigated with PSG in the acute phase, 104 were again studied 3 months after stroke symptom onset and compared with 162 controls. The acute phase of stroke/TIA was associated with sleep disruption, which significantly improved in the chronic phase, but remained worse than controls (total sleep time improve from 318.8 ± 90.8 to 348.4 ± 81.5 min, compared to 388.2 ± 71.3 in controls, sleep latency from 49.9 ± 58.4 to 27.9 min, compared to 20.2 ± 22 in controls, sleep efficiency from 58.2 ± 18.1% to 27.9 ± 36.4 min, compared to 83.4 ± 10.3% in controls, wakefulness after sleep onset percentage from 36.5 ± 17.3 to 29.3 ± 15.6, compared to 13.2 ± 9.2 in controls). The percentage of REM sleep was negatively associated with stroke severity, whereas stroke topography did not correlate with sleep parameters. CONCLUSIONS: This study confirmed a severe sleep disruption in the acute phase of stroke. Although a significant improvement of sleep quality was observed during the three months after stroke, sleep architecture did not normalize. In particular, sleep efficiency and REM sleep seem to be particularly affected by stroke in the acute phase, with a relative preservation of NREM sleep. We suggest that these sleep architecture changes represent a persistent marker of brain damage due to stroke. Further studies are needed to assess the relationship with stroke topographic and outcome.

Focal lesions induce large-scale percolation of sleep-like intracerebral activity in awake humans.

Focal cortical lesions are known to result in large-scale functional alterations involving distant areas; however, little is known about the electrophysiological mechanisms underlying these network effects. Here, we addressed this issue by analysing the short and long distance intracranial effects of controlled structural lesions in humans. The changes in Stereo-Electroencephalographic (SEEG) activity after Radiofrequency-Thermocoagulation (RFTC) recorded in 21 epileptic subjects were assessed with respect to baseline resting wakefulness and sleep activity. In addition, Cortico-Cortical Evoked Potentials (CCEPs) recorded before the lesion were employed to interpret these changes with respect to individual long-range connectivity patterns. We found that small structural ablations lead to the generation and large-scale propagation of sleep-like slow waves within the awake brain. These slow waves match those recorded in the same subjects during sleep, are prevalent in perilesional areas, but can percolate up to distances of 60 mm through specific long-range connections, as predicted by CCEPs. Given the known impact of slow waves on information processing and cortical plasticity, demonstrating their intrusion and percolation within the awake brain add key elements to our understanding of network dysfunction after cortical injuries.

The evolution of the narcolepsy concept in Russia: A historical view.

Following the first descriptions of narcolepsy with cataplexy by Westphal, Gelineau, and Fischer (1878-1880), Russian authors started to report on "narcolepsy cases" in 1894. It was, however, only in 1925 that Mankovsky reported a (postencephalitic) case, satisfying current diagnostic criteria for the disease. In the following 66 years (the last publication appeared in 1991), Russian authors including Davidenkov, Vein, and Yakhno made interesting contributions on the clinical features, neurophysiological correlates (e.g., sleep states and boundary dyscontrol), pathogenesis (e.g., hypothalamic origin), etiology (e.g., infectious, postvaccinal triggers, focal encephalitis), and treatment (e.g., use of sodium oxybate) of narcolepsy. Until recently, Pavlov's theory of narcolepsy as a "cortical excitatory-inhibitory phenomenon" strongly influenced the Russian view on the disease, contrasting with the current neurobiological insights acknowledged internationally. A Narcolepsy Network, including currently 10 member centers, was recently founded to promote knowledge, awareness, management, and research on this still poorly known disease in Russia.

EAN/ERS/ESO/ESRS statement on the impact of sleep disorders on risk and outcome of stroke.

BACKGROUND: Sleep disorders are highly prevalent in the general population and may be linked in a bidirectional fashion to stroke, which is one of the leading causes of morbidity and mortality. AIM: Four major scientific societies established a task force of experts in neurology, stroke, respiratory medicine, sleep medicine and methodology to critically evaluate the evidence regarding potential links and the impact of therapy. MATERIALS AND METHODS: Thirteen research questions were evaluated in a systematic literature search using a stepwise hierarchical approach: first, systematic reviews and meta-analyses; second, primary studies post-dating the systematic reviews/meta-analyses. A total of 445 studies were evaluated and 88 were included. Statements were generated regarding current evidence and clinical practice. RESULTS: Severe obstructive sleep apnoea (OSA) doubles the risk for incident stroke, especially in young to middle-aged patients. Continuous positive airway pressure (CPAP) may reduce stroke risk, especially in treatment-compliant patients. The prevalence of OSA is high in stroke patients and can be assessed by polygraphy. Severe OSA is a risk factor for recurrence of stroke and may be associated with stroke mortality, whilst CPAP may improve stroke outcome. It is not clear if insomnia increases stroke risk, whilst the pharmacotherapy of insomnia may increase it. Periodic limb movements in sleep (PLMS), but not restless limb syndrome (RLS), may be associated with an increased risk of stroke. Preliminary data suggest a high frequency of post-stroke insomnia and RLS and their association with a less favourable stroke outcome, whilst treatment data are scarce. DISCUSSION/CONCLUSION: Overall, the evidence base is best for OSA relationship with stroke and supports active diagnosis and therapy. Research gaps remain especially regarding insomnia and RLS/PLMS relationships with stroke.

SAS CARE 2 - a randomized study of CPAP in patients with obstructive sleep disordered breathing following ischemic stroke or transient ischemic attack.

OBJECTIVE/BACKGROUND: The benefit of Continuous Positive Airway Pressure (CPAP) treatment following ischemic stroke in patients with obstructive sleep-disordered breathing (SDB) is unclear. We set out to investigate this open question in a randomized controlled trial as part of the SAS-CARE study. PATIENTS/METHODS: Non-sleepy patients (ESS < 10) with ischemic stroke or transient ischemic attack (TIA) and obstructive SDB (AHI ≥ 20) 3 months post-stroke were randomized 1:1 to CPAP treatment (CPAP+) or standard care. Primary outcome was the occurrence of vascular events (TIA/stroke, myocardial infarction/revascularization, hospitalization for heart failure or unstable angina) or death within 24 months post-stroke. Secondary outcomes included Modified Rankin Scale (mRS) and Barthel Index. RESULTS: Among 238 SAS-CARE patients 41 (17%) non-sleepy obstructive SDB patients were randomized to CPAP (n = 19) or standard care (n = 22). Most patients (80%) had stroke and were males (78%), mean age was 64 ± 7 years and mean NIHSS score 0.6 ± 1.0 (range: 0-5). The primary endpoint was met by one patient in the standard care arm (a new stroke). In an intent-to treat analysis disregarding adherence, this corresponds to an absolute risk difference of 4.5% or an NNT = 22. mRS and Barthel Index were stable and similar between arms. CPAP adherence was sufficient in 60% of evaluable patients at month 24. CONCLUSION: No benefit of CPAP started three months post-stroke was found in terms of new cardio- and cerebrovascular events over 2 years. This may be related to the small size of this study, the mild stoke severity, the exclusion of sleepy patients, the delayed start of treatment, and the overall low event rate.