Brain-Computer Interfaces for Communication in Patients with Disorders of Consciousness: A Gap Analysis and Scientific Roadmap.

BACKGROUND: We developed a gap analysis that examines the role of brain-computer interfaces (BCI) in patients with disorders of consciousness (DoC), focusing on their assessment, establishment of communication, and engagement with their environment. METHODS: The Curing Coma Campaign convened a Coma Science work group that included 16 clinicians and neuroscientists with expertise in DoC. The work group met online biweekly and performed a gap analysis of the primary question. RESULTS: We outline a roadmap for assessing BCI readiness in patients with DoC and for advancing the use of BCI devices in patients with DoC. Additionally, we discuss preliminary studies that inform development of BCI solutions for communication and assessment of readiness for use of BCIs in DoC study participants. Special emphasis is placed on the challenges posed by the complex pathophysiologies caused by heterogeneous brain injuries and their impact on neuronal signaling. The differences between one-way and two-way communication are specifically considered. Possible implanted and noninvasive BCI solutions for acute and chronic DoC in adult and pediatric populations are also addressed. CONCLUSIONS: We identify clinical and technical gaps hindering the use of BCI in patients with DoC in each of these contexts and provide a roadmap for research aimed at improving communication for adults and children with DoC, spanning the clinical spectrum from intensive care unit to chronic care.

Intrinsic stenosing and occlusive pathologies of the vertebral artery: A narrative review.

Intrinsic pathologies of the vertebral arteries, such as atherosclerosis, dissection, fibromuscular dysplasia, radionecrosis and vasculitis, are important causes of vertebrobasilar insufficiency and cerebrovascular events. This review focuses on non-aneurysmal intrinsic stenosing and occlusive pathologies, covering their epidemiology, diagnosis, and treatment options. It also provides a detailed summary of key clinical presentations and syndromes, including an in-depth examination of lateral medullary syndrome, historically known as Wallenberg's syndrome, which is arguably the most emblematic condition resulting from vertebral artery involvement and is depicted in an illustrative cartoon.

Osteovascular Conflicts in the Neck Region and Cerebrovascular Events: Illustrative Cases and Literature Review.

STUDY DESIGN: Literature Review. OBJECTIVE: Abnormal bone structures in the neck can cause headache, neck pain, and difficulty swallowing, but also cerebrovascular events. We introduce the term "osteovascular conflicts" to describe this phenomenon. The objective of this study was to conduct a literature review of such conflicts involving the anterior and posterior cerebral circulation. Furthermore, we aimed at presenting additional illustrative cases from our institution both for increasing awareness for unusual osteovascular conflicts, and for assessing the practice and care of such patients. METHODS: We focused on osteovascular conflicts in the neck leading to cerebrovascular events related to an abnormal bone structure causing arterial or venous compression, dissection, and/or occlusion. We excluded pure vascular forms without cerebrovascular repercussions. Our PubMed/MEDLINE search for articles published in any language and for which an English abstract was available (from 1966 to 2022) included Eagle's neurovascular, bow hunter's syndrome, and golfer's stroke, excluding trauma-induced artery dissections or compressions and those concerning systemic bone disorders. We also provided illustrative cases collected by the authors. RESULTS: All studies were either case reports or small case series. We found 82 cases of Eagle's neurovascular, 258 of bow hunter's syndrome, and 17 golfer's stroke cases. Mean ages were 52, 48, and 47 years, respectively. Male predominance was evident: 81% for Eagle's, 74% for bow hunter's, and 93% for golfer's. CONCLUSION: Osteovascular conflicts are rare but important causes of cerebrovascular events and often go unrecognised. A greater awareness of cerebrovascular symptoms related to these conflicts can facilitate early diagnosis and treatment.

A Focus on Subtle Signs and Motor Behavior to Unveil Awareness in Unresponsive Brain-Impaired Patients: The Importance of Being Clinical.

Brain-injured patients in a state of cognitive motor dissociation (CMD) exhibit a lack of command following using conventional neurobehavioral examination tools but a high level of awareness and language processing when assessed using advanced imaging and electrophysiology techniques. Because of their behavioral unresponsiveness, patients with CMD may seem clinically indistinguishable from those with a true disorder of consciousness that affects awareness on a substantial level (coma, vegetative state/unresponsive wakefulness state, or minimally conscious state minus). Yet, by expanding the range of motor testing across limb, facial, and ocular motricity, we may detect subtle, purposeful movements even in the subset of patients classified as vegetative state/unresponsive wakefulness state. We propose the term of clinical CMD to describe patients showing these slight but determined motor responses and exhibiting a characteristic akinetic motor behavior as opposed to a pyramidal motor system behavior. These patients may harbor hidden cognitive capabilities and significant potential for a good long-term outcome. Indeed, we envision CMD as ranging from complete (no motor response) to partial (subtle clinical motor response) forms, falling within a spectrum of progressively better motor output in patients with considerable cognitive capabilities. In addition to providing a decisional flowchart, we present this novel approach to classification as a graphical model that illustrates the range of clinical manifestations and recovery trajectories fundamentally differentiating true disorders of consciousness from the spectrum of CMD.

Clinical Cognitive Motor Dissociation: A Case Report Showing How Pitfalls Can Hinder Early Clinical Detection of Awareness.

This study presents the case of a brain-injured patient whose pathological awakening after coma and absence of interaction led to a diagnosis of lack of consciousness when standard clinical scales were administered. However, we were able to demonstrate conscious perception in this patient from initial clinical assessments using the Motor Behaviour Tool in the acute stage, complemented by a systematic search for potential obstacles blocking his execution of motor responses (pitfalls). This refinement of the diagnosis enabled prediction of a favourable outcome despite the severity of the lesions, with the patient's evolution confirming our prediction. Faced with an unresponsive patient, every specialist should go beyond the absence of response with the standard scores, consider the possibility of a hidden consciousness and look for rigorous ways of proving it.

Intima-Media Thickness and Pulsatility Index of Common Carotid Arteries in Acute Ischaemic Stroke Patients with Diabetes Mellitus.

Ultrasonographic parameters such as the common carotid artery (CCA) pulsatility index (PI) and CCA intima-media thickness (IMT) have been associated with an increased mortality and risk of recurrent stroke, respectively. We hypothesized that these ultrasonographic parameters may be useful for monitoring diabetic patients after an acute stroke. We analysed retrospective data of consecutive acute ischaemic stroke patients from the ASTRAL registry who underwent pre-cerebral ultrasonographic evaluation within 7 days of symptom onset. We compared clinical, demographic, radiological and ultrasonographic parameters in diabetic versus non-diabetic patients (univariable and multivariable analyses) and the association of these parameters with CCA PI and CCA IMT. We analysed 1507 carotid duplex ultrasound examinations from patients with a median age of 74 years. Cardiovascular co-morbidities, including hypertension, hypercholesterolemia, obstructive sleep apnoea syndrome, higher body-mass index (BMI) and peripheral artery disease, were associated with diabetes mellitus (DM). Diabetics were more often under antiplatelet therapy and had atrial fibrillation at admission. Diabetic patients showed an increased CCA PI and IMT in line with more atherosclerotic changes on acute CTA compared to non-diabetic patients. Taking IMT as the dependent variable in a second analysis, DM, higher age, hypertension, smoking and CCA PI were associated with higher IMT. Taking CCA PI as the dependent variable in a third analysis, DM, higher age and higher NIHSS at admission were associated with higher CCA PI values. Increased IMT was also associated with higher PI. We show that CCA PI and IMT are higher in diabetic patients in the first week after an initial stroke.

Preconditioning by Preceding Ischemic Cerebrovascular Events.

Background Emerging yet contrasting evidence from animal and human studies associates ischemic preconditioning with improvement of subsequent stroke severity, although long-term outcome remains unclear. The purpose of this study was to analyze how preceding cerebral ischemic events influence subsequent stroke severity and outcome. Methods and Results Data for this retrospective cohort study were extracted from ASTRAL (Acute Stroke Registry and Analysis of Lausanne). This registry includes a sample of all consecutive patients with acute ischemic strokes admitted to the stroke unit and/or intensive care unit of the Lausanne University Hospital, Switzerland. We investigated associations between preceding ischemic events (transient ischemic attacks or ischemic strokes) and the impact on subsequent stroke severity and clinical improvement within 24 hours, measured through National Institute of Health Stroke Scale, as well as 3-month outcome, determined through a shift in the modified Rankin Scale. Of 3530 consecutive patients with ischemic stroke (43% women, median age 73 years), 1001 (28%) had ≥1 preceding cerebral ischemic events (45% transient ischemic attack, 55% ischemic stroke; 31% multiple events). After adjusting for multiple prehospital, clinical, and laboratory confounders, admission stroke severity was significantly lower in patients preconditioned through a preceding ischemic event, but 24-hour improvement was not significant and 3-month outcome was unfavorable. Conclusions Preceding ischemic events were independently associated with a significant reduction in subsequent stroke severity but worsened long-term clinical outcome. These results, if confirmed by future randomized studies, may help design neuroprotective strategies. The unfavorable effect on stroke outcome is probably a consequence of the cumulative disability burden after multiple ischemic events.

[Neurorehabilitation in the acute and post-acute phase: what did we learn from the first wave of COVID-19?] / Neurorééducation en phases aiguë et postaiguë : qu'avons-nous appris de la première vague de Covid-19 ?

The majority of patients with Coronavirus disease 2019 (COVID-19) present mild to moderate illness and recover without hospitalization. Nevertheless, 5 % of cases require hospitalization in the intensive care unit, with 15 % of them showing severe central and peripheral nervous system manifestations. These patients should be considered high risk patients and their management must include prevention of a potential accompanying cascade of negative factors. In order to optimize care, it is essential that signs of neurological damage are searched for as early as in intensive care so that appropriate neurorehabilitation can be started immediately and continued in a specific unit for patients with neurological sequelae at post-acute and outpatient phases.

La majorité des patients atteints par la maladie due au coronavirus 2019 (Covid-19) présente une évolution plutôt favorable. Cependant 5 % nécessitent une hospitalisation aux soins intensifs, dont 15 % présentent des atteintes sévères des systèmes nerveux central et périphérique. Ces patients doivent être considérés comme des personnes à haut risque de développer des séquelles graves et leur plan de traitement doit nécessairement impliquer la prévention d'une potentielle cascade de facteurs négatifs concomitants. Afin d'optimiser une telle prise en charge, il est primordial que les premiers signes d'atteintes neurologiques soient détectés dès les soins intensifs et qu'une neurorééducation puisse être débutée précocement et poursuivie dans une filière de patients neuro-lésés en phase postaiguë, puis en ambulatoire.

Predictors of the pulsatility index in the middle cerebral artery of acute stroke patients.

Cervical and transcranial Doppler (TCD) are widely used as non-invasive methods in the evaluation of acute ischemic stroke (AIS) patients. High-grade carotid artery stenosis induces haemodynamic changes such as collateral flow and a so-called post-stenotic flow pattern of the middle cerebral artery (MCA), which appears flattened, with a reduction of the velocity difference between systole and diastole. We studied the influence of carotid artery stenosis and other variables on the flow pattern in the MCA using the pulsatility index (PI), a quantitative TCD parameter reflecting the flow spectrum in a large of cohort AIS patients. We performed ultrasound examinations of 1825 AIS patients at the CHUV from October 2004 to December 2014. We extracted patient characteristics from the ASTRAL registry. Carotid stenosis severity was classified as < 50%, 50-70%, 70-90% and > 90%, or occlusion, according to Doppler velocity criteria. We first determined variables associated with stenosis grade. Then we performed a multivariate analysis after adjusting for baseline differences, using MCA PI as dependent variable. Carotid stenosis > 70% (- 0.07) and carotid stenosis > 90%, or occlusion (- 0.14) and left side (- 0.02) are associated with lower MCA PI values. Age (+0.006 PI units per decade), diabetes (+0.07), acute ischemic changes on initial CT (+0.03) and severe plaque morphology (+0.18) are associated with higher MCA PI values. We found a number of clinical and radiological conditions that significantly influence the PI of the MCA, including high-grade ipsilateral carotid stenosis in AIS patients. We provide for the first time a quantitative evaluation of the effect of these influencing factors from a large cohort of AIS patients.

Factors Associated With Focal Computed Tomographic Perfusion Abnormalities in Supratentorial Transient Ischemic Attacks.

BACKGROUND AND PURPOSE: Computed tomographic perfusion (CTP) is useful in diagnosis of patients with transient focal neurological symptoms. In acute imaging of patients with a suspected transient ischemic attack (TIA), it remains unclear which patients develop focal perfusion abnormalities (FPA), that is, hypoperfusion or hyperperfusion. We aimed at determining independent factors associated with FPA in patients with supratentorial TIAs. METHODS: We prospectively collected consecutive patients with supratentorial TIAs defined by the traditional time-based definition who underwent CTP within 24 hours of symptom onset. We recorded demographics, risk factors, clinical features, severity, and timing from onset. We documented the Age, Blood Pressure, Clinical Features, Duration, and Diabetes (ABCD2) scores, vascular territories, and presence of relevant arterial pathology. Variables were tested for an association with FPA with univariate and multivariate analyses. RESULTS: A hundred and ten of 265 patients (42%) with supratentorial TIAs had FPA on CTP. Acute noncontrast computed tomography showed early ischemic lesions in 6%, and acute/subacute magnetic resonance imaging was pathological in 52 of the 109 cases (47.7%) where it was performed. Clinical factors associated with FPA were high-admission National Institutes of Health Stroke Scale (odds ratio [OR], 1.22), right hemispheric TIA (OR, 3.09), and cardioembolic mechanism (OR, 2.19). Persistence of symptoms during CTP (OR, 2.59), shorter duration of TIA (OR, 0.93), major intracranial arterial pathology (OR, 12.5), and extracranial arterial occlusion (OR, 7.44) were also associated with FPA. CONCLUSIONS: Supratentorial TIAs are often associated with FPA in CTP, even after symptom resolution. FPAs are frequent in severe TIAs and those associated with cardioembolism or specific arterial pathologies. These findings can help clinicians in accurate diagnosis of TIA and its underlying mechanisms.

Beauty parlor stroke revisited: An 11-year single-center consecutive series.

BACKGROUND: Hairdresser-related ischemic cerebrovascular events (HICE) are attributed to compression of vertebral arteries or cervical artery dissections. We determined their frequency, mechanisms, localization and outcome in a pre-specified study. METHODS: We prospectively collected ischemic strokes and transient ischemic attacks occurring in relation to a hairdresser visit from 2002 to 2013, using consecutive data from an ischemic stroke registry (ASTRAL). HICE were compared to all other acute ischemic strokes in ASTRAL. RESULTS: We identified 10 HICE (9 strokes and 1 transient ischemic attack). Age and anterior-posterior distribution were similar with a significantly higher rate of females (90% vs. 43%, p = 0.02) in the HICE group compared to ASTRAL. Patients with HICE had significantly lower incidence of hyperlipidemia (30% vs. 73%) and diabetes (0% vs. 19%). The mechanisms of HICE were diverse: carotid artery dissection (n = 2), cardiac (n = 2), lacunar (n = 2), other determined (n = 2) and unknown etiology (n = 2). Two HICE with atherosclerotic intracranial disease were possibly caused by acute hemodynamic changes related to systemic hypotension during hot air hair drying. Unadjusted favorable outcome at three months seemed to be better in HICE (90% vs. 57%), and 12-month mortality and recurrences were similar. CONCLUSIONS: HICE may occur frequently in females without a predilection for the posterior circulation. Although some HICE may occur by chance (pseudo-HICE), hairdresser visits may have a causal role in some cases, including cervical artery dissection or hemodynamic compromise related to pre-existing arterial disease (true HICE). Available data are insufficient for specific preventive recommendations.

Portal Vein Embolization Followed by Liver Resection versus Liver Resection Alone: a Comparison of Liver Regeneration Dynamics.

BACKGROUND/AIMS: Portal vein embolization (PVE) is an accepted procedure, which, by redirecting portal vein flow toward specific hepatic segments, is able to pre-operatively increase the volume of the future liver remnant (FLR). The consequent reduction of liver dysfunction risk enables to extend the number of pa tients eligible for major hepatic resection. This study aims at comparing liver regeneration dynamics and long-term volumetric recovery after major hepatic re section preceded by PVE versus major hepatic resec tion not preceded by PVE. METHODOLOGY: Data from 24 consecutive patients who underwent PVE prior to major hepatic resection were collected and compared to 24 consecutive patients who underwent major hepatic resection, but on whom PVE was not performed. RESULTS: A significant growth of the FLR was observed after PVE. The liver remnant underwent a further regeneration burst after resection, with long-term volumetric recovery rates around 85% of the estimated total liver volume, similar to those observed for the control group and to those previously documented in the relevant literature. CONCLUSION: PVE gives a first impulse to liver regeneration before liver resection without compromising further regeneration after resection, resulting in long-term volumetric recovery rates similar to those known for regeneration after liver resection without prior PVE.