Improving the evaluation of comatose and post-comatose patients and boosting their cognitive functions – CogniComa

Comatose and post-comatose patients represent an important human, social and economic issue. Improving diagnosis, prognosis and treatment of these patients has become a major challenge for research in the last 15 years. Various paradigms and methodologies have been developed to improve evaluation and have shown the preservation of sensory and cognitive functions in some patients, even though no behavioral reactions could be observed with clinical assessment. However these paradigms are difficult to implement in clinical practice, since they use very complex methodologies (such as functional Magnetic Resonance Imaging) or paradigms (e.g. requiring patients to follow instructions) and they often have a low level of sensitivity. Moreover, while cerebral plasticity is a key for recovery, only few of these previous studies have attempted to improve behavior and/or cerebral functions.
In the first part of the project (task 2), we aim at improving the sensitivity and reliability of the cerebral/cognitive evaluation of comatose and post-comatose patients. The first goal is to develop new bedside high-density electroencephalographic (hd-EEG) methods to assess the preservation of different cerebral functions: brain network organization at rest, and residual perceptual and cognitive abilities following sensory stimulation. The second goal is to better characterize the evolution of the patient’s cerebral activity, with both short-term and long-term views, i.e. using continuous (24hour recordings) and longitudinal assessments (repeated evaluations). These two goals contrast with the way the majority of evaluations are done nowadays, i.e. using only one snapshot of a patient’s function, making the evaluation excessively dependent on momentary fluctuations of the patient’s state and missing to integrate crucial information related to patient recovery.
The second part of the project (task 3) aims to develop new rehabilitation and therapeutic strategies, by boosting the preserved cerebral networks/functions of the patients. We will develop complementary strategies: autobiographical sensory stimulation, pharmacological modulation of brain plasticity, and non-invasive brain stimulations (transcranial direct current stimulation). Recovery of cerebral and cognitive functions will be measured by current clinical EEG tests (previously developed by our teams), as well as by our new bedside hd-EEG strategies, i.e. at rest or using auditory stimulations (task 2). This objective is novel and original in comparison to previous research.
These investigations will contribute to the third part of the project (task 4), which are the development and the validation of a hierarchically organized evaluation battery within our national multi-centric program. The most sensitive hd-EEG strategies, at rest and using external stimulations, will be included in the battery. We will also put an emphasis on identifying contexts in which brain plasticity may be promoted.
To summarize, our approach will contribute to: (i) establish a more precise, hierarchically organized and reliable evaluation of the deficits throughout recovery, thus improving severely brain-injured patients’ diagnosis and prognosis (ii) assess the clinical and electrophysiological impact of novel pharmacologic and non-pharmacologic therapeutic interventions.
This ambitious project will foster for the first time a strong cooperation between different research and clinical centers in France (Lyon, Paris, Toulouse) working on the evaluation of comatose and post-comatose patients. It will help identifying the relevance and complementarities of different evaluation tools, and aims to validate these methods across large population of patients. The establishment of a strong national cooperation will also help promote and organize currently sparse, but existing collaborations with two international groups (in Cambridge, UK, and Liège, Belgium).