Trajectories of self-reported daytime sleepiness post-ischemic stroke and transient ischemic attack: A propensity score matching study versus non-stroke patients.

INTRODUCTION: Severe sleep apnea (SA) affects one-third of stroke patients. Sleepiness, one of the cardinal symptoms of SA, negatively impacts functional stroke outcomes. The impact of continuous positive airway pressure (CPAP) on post-stroke sleepiness is poorly described. We aimed to compare through a propensity score matching the trajectories of self-reported sleepiness post-stroke with matched individuals including SA patients adherent or not to CPAP. PATIENTS AND METHODS: Sixty five (80.2%) ischemic stroke and 16 (19.8%) TIA patients (median [Q1;Q3] age = 67.0 [58.0;74.0] years, 70.4% male, body mass index [BMI] = 26.1 [24.5;29.8] kg·m-2, admission NIHSS = 3.0 [1.0;5.0]), with polysomnography and an Epworth Sleepiness Scale (ESS) performed within 1 year following stroke and with a follow-up ESS (delay = 236 [147;399] days) were included in the analysis. A 2:1 propensity score matching based on age, gender, BMI, and the apnea-hypopnea index was performed to identify 162 matched individuals referred for SA suspicion, free of stroke or TIA. Multivariable negative binomial regression models were performed to identify the determinants of sleepiness trajectories post-stroke. RESULTS: Baseline ESS was comparable between stroke/TIA and matched individuals (median [Q1; Q3] ESS = 7 [4;10] versus 6 [4;10], p = 0.86). The range of improvement in ESS was higher in stroke patients compared to controls (∆ESS = -2 [-4;1] vs -1 [-3;2], p = 0.03). In multivariable analysis, comorbid SA and CPAP treatment did not influence trajectories of sleepiness post-stroke. DISCUSSION AND CONCLUSION: Sleepiness improvement was unexpectedly higher in stroke patients compared to matched individuals, with no significant influence of comorbid SA and CPAP on its trajectory. Sleepiness may not be primarily indicative of SA in stroke or TIA patients.

Sleep-disordered breathing and ventilatory chemosensitivity in first ischaemic stroke patients: a prospective cohort study.

RATIONALE: Sleep-disordered breathing (SDB) is highly prevalent after stroke. The clinical and ventilatory chemosensitivity characteristics of SDB, namely obstructive, central and coexisting obstructive and central sleep apnoea (coexisting sleep apnoea) following stroke are poorly described. OBJECTIVE: To determine the respective clinical and ventilatory chemosensitivity characteristics of SDB at least 3 months after a first ischaemic stroke. METHODS: Cross-sectional analysis of a prospective, monocentric cohort conducted in a university hospital. 380 consecutive stroke or transient ischaemic attack patients were screened between December 2016 and December 2019. MEASUREMENTS AND MAIN RESULTS: Full-night polysomnography, and hypercapnic ventilatory response were performed at a median (Q1; Q3) time from stroke onset of 134.5 (97.0; 227.3) days. 185 first-time stroke patients were included in the analysis. 94 (50.8%) patients presented no or mild SDB (Apnoea-Hypopnoea Index <15 events/hour of sleep) and 91 (49.2%) moderate to severe SDB, of which 52 (57.1%) presented obstructive sleep apnoea and 39 (42.9%) coexisting or central sleep apnoea. Obstructive sleep apnoea patients significantly differed regarding their clinical presentation from patients with no or mild SDB, whereas there was no difference with coexisting and central sleep apnoea patients. The latter presented a higher frequency of cerebellar lesions along with a heightened hypercapnic ventilatory response compared with no or mild SDB patients. CONCLUSION: SDB in first-time stroke patients differ in their presentation by their respective clinical traits and ventilatory chemosensitivity characteristics. The heightened hypercapnic ventilatory response in coexisting and central sleep apnoea stroke patients may orientate them to specific ventilatory support.

Probabilistic mapping of language networks from high frequency activity induced by direct electrical stimulation.

Direct electrical stimulation (DES) at 50 Hz is used as a gold standard to map cognitive functions but little is known about its ability to map large-scale networks and specific subnetwork. In the present study, we aim to propose a new methodological approach to evaluate the specific hypothesis suggesting that language errors/dysfunction induced by DES are the result of large-scale network modification rather than of a single cortical region, which explains that similar language symptoms may be observed after stimulation of different cortical regions belonging to this network. We retrospectively examined 29 patients suffering from focal drug-resistant epilepsy who benefitted from stereo-electroencephalographic (SEEG) exploration and exhibited language symptoms during a naming task following 50 Hz DES. We assessed the large-scale language network correlated with behavioral DES-induced responses (naming errors) by quantifying DES-induced changes in high frequency activity (HFA, 70-150 Hz) outside the stimulated cortical region. We developed a probabilistic approach to report the spatial pattern of HFA modulations during DES-induced language errors. Similarly, we mapped the pattern of after-discharges (3-35 Hz) occurring after DES. HFA modulations concurrent to language symptoms revealed a brain network similar to our current knowledge of language gathered from standard brain mapping. In addition, specific subnetworks could be identified within the global language network, related to different language processes, generally described in relation to the classical language regions. Spatial patterns of after-discharges were similar to HFA induced during DES. Our results suggest that this new methodological DES-HFA mapping is a relevant approach to map functional networks during SEEG explorations, which would allow to shift from "local" to "network" perspectives.