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Impact on clinical outcome of continuous EEG monitoring in patients with disorders of consciousness: a randomized controlled trial

English title Impact on clinical outcome of continuous EEG monitoring in patients with disorders of consciousness: a randomized controlled trial
Applicant Rossetti Andrea
Number 169379
Funding scheme Project funding (Div. I-III)
Research institution Service de Neurologie Département des Neurosciences Cliniques CHUV
Institution of higher education University of Lausanne - LA
Main discipline Neurology, Psychiatry
Start/End 01.05.2017 - 31.10.2022
Approved amount 555'604.00
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All Disciplines (2)

Neurology, Psychiatry
Biomedical Engineering

Keywords (4)

Outcome; Consciousness impairment; EEG monitoring; Quantitative EEG analysis

Lay Summary (French)

Impact on clinical outcome of continuous electroencephalography in patients with disorders of consciousness
Lay summary

L’électroencéphalogramme continu (cEEG) est un outil non-invasif pour surveiller l’activité électrique cérébrale Chez les patients avec atteinte de la conscience, le cEEG améliore la détection de crises épileptiques. Cependant, l’impact sur le pronostic clinique n’a pas été clairement étudié. Le cEEG est gourmand en termes de temps et ressources, comparé à l’électroencéphalogramme de routine (rEEG, qui dure typiquement 20-30 minutes) : si en Amérique du Nord il est utilisé de manière croissante, la vaste majorité des centres européens n’ont pas les ressources pour une implémentation. De plus, le rôle de l’analyse quantitative du signal EEG, au delà de l’analyse visuelle, concernant le pronostic reste indéterminé.

Le but de cette étude est de déterminer si le cEEG est corrélé à une amélioration du pronostic clinique chez des patients avec une atteinte de la conscience, et d’explorer le rôle pronostique de l’analyse quantitative de l’EEG.

Dans cet essai randomisé contrôlé multicentrique (5 hôpitaux suisses), des patients adultes avec atteinte de la conscience et nécessitant un EEG seront randomisés 1 :1 vers un cEEG durant 30-48 heures ou vers 2 rEEG dans le même lapse de temps. La mortalité à 6 mois représentera l’outcome primaire ; selon une estimation préalable il faudra 350 patients pour démontrer une différence significative. Les outcomes secondaires seront, entre autres : le devenir fonctionnel, la proportion de crises épileptiques détectées, et les coûts. De même, des analyses quantitatives du signal seront effectuées sur les tracés cEEG et rEEG et corrélées  au pronostic.

Cette étude clarifiera si le cEEG a un impact significatif et notable sur le pronostic clinique, définira son efficacité économique, et identifiera les analyses quantitatives du signal EEG corrélées au pronostic. Ses résultats ont le potentiel de générer un impact majeur, en influençant la prise en charge de patients avec une atteinte de la conscience.

Direct link to Lay Summary Last update: 11.04.2017

Responsible applicant and co-applicants

Associated projects

Number Title Start Funding scheme
143780 Early electrophysiological correlates of brain injury and outcome in comatose patients after cardiac arrest 01.03.2013 Interdisciplinary projects


Background: Continuous video-EEG monitoring (cEEG) is a non-invasive tool to monitor the electrical brain function; it significantly improves seizure or status epilepticus detection in comatose patients in intensive care units (ICUs), which often do not show any specific clinical correlates. Recently, the European Society of Intensive Care Medicine published guidelines regarding the use of cEEG in the ICUs, recommending it for most patients with consciousness disorders. cEEG is time- and resource consuming as compared to routine spot EEG (rEEG, typically lasting 20-30 minutes). While centers in North America have been using it increasingly, most European - and all Swiss - hospitals still do not have enough resources to comply with these guidelines. In addition, while the superiority of cEEG to detect non-convulsive seizures or status epilepticus is proven, only one population-based study based on discharge diagnoses suggested that cEEG may improve patients’ outcome. Current guidelines are thus based upon weak evidence and expert opinions. If cEEG leads to improved patients’ care remains elusive. Moreover, little attention has been drawn towards quantitative EEG information beyond visual analysis, and the impact of such information on diagnosis, treatment, and outcome remains unclear.Aim: To assess whether the use of cEEG in patients with consciousness impairment is related to an improvement of functional outcome, and to address the prognostic role of quantitative network EEG analyses in this cohort. Subsequently, a cost analysis will be performed.Methods: In this multicenter randomized controlled trial, adults with a Glasgow Coma Score (GCS) ?11, regardless of etiologies, will be randomized 1:1 to cEEG for 30-48 hours or two rEEG, using standard interpretations. Patients with previously detected seizures or status epilepticus will be excluded, as cEEG may represent the standard of care in those situations. Demographics, etiology, Charlson Comorbidity Index, GCS, diagnosis leading to EEG, mechanical ventilation, and subsequent use of rEEG/cEEG will be collected. The primary outcome will be mortality at 6 months. Secondary outcomes will assess functional outcome at 4 weeks and 6 months, seizure/status epilepticus detection rate and time to detection, rate of infections, duration of ICU stay and acute hospital stay, change in patient management (antiepileptic drug introduced, increased, or stopped, brain imaging), and reimbursement. Analyses will compare the two interventional groups (intention to diagnose) regarding outcome, as a whole and stratified according to etiological subgroups, and other variables of interest. Additionally, lope cross correlation and horizontal visibility graphs will be applied to compute a weighted adjacency matrix consisting of all the pairwise interdependences between EEG signals, in order to characterize the integrative and segregative characteristics of the underlying functional brain networks and compare their relationship with the primary outcome. According to a previous estimate, patients with consciousness disorders undergoing cEEG have a 75% survival rate; while patients w/o cEEG 61%. Using a power of 0.8, an a error of 0.05, and a 2-side approach, 2x174 patients would be needed to detect this significant difference in survival. Expected impact: This study will clarify if cEEG monitoring has a significant impact on functional outcome and define its cost effectiveness, and if network EEG analysis has a role in outcome prognostication. The results of this study will have a considerable potential to influence clinical practice regarding EEG and treatment of patients with altered levels of consciousness. If the study results would indicate that cEEG significantly improves outcome of patients with altered consciousness, this will lead to the urgent need for implementation of cEEG with consecutive substantial impact on health care and resource allocation in larger Swiss and European hospitals.