The Clinical Diagnostic Utility of Electrophysiological Techniques in Assessment of Patients With Disorders of Consciousness Following Acquired Brain Injury: A Systematic Review.

OBJECTIVE: To investigate the diagnostic utility of electrophysiological recordings during active cognitive tasks in detecting residual cognitive capacities in patients with disorders of consciousness (DoC) after severe acquired brain injury. DESIGN: Systematic review of empirical research in MEDLINE, Embase, PsycINFO, and Cochrane from January 2002 to March 2016. MAIN MEASURES: Data extracted included sample size, type of electrophysiological technique and task design, rate of cognitive responders, false negatives and positives, and excluded subjects from the study analysis. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) was used for quality appraisal of the retrieved literature. RESULTS: Twenty-four studies examining electrophysiological signs of command-following in patients with DoC were identified. Sensitivity rates in healthy controls demonstrated variable accuracy across the studies, ranging from 71% to 100%. In patients with DoC, specificity and sensitivity rates varied in the included studies, ranging from 0% to 100%. Pronounced heterogeneity was found between studies regarding methodological approaches, task design, and procedures of analysis, rendering comparison between studies challenging. CONCLUSION: We are still far from establishing precise recommendations for standardized electrophysiological diagnostic procedures in DoC, but electrophysiological methods may add supplemental diagnostic information of covert cognition in some patients with DoC.

Clinical assessment of patients with disorders of consciousness.

The study of pathological impairments of consciousness, as they can appear in severely brain injured patients, can be particularly useful to better clarify cognitive processes and cerebral substrates which underlie consciousness. In this review, we will introduce the disorders of consciousness that can be presented by severely brain-injured patients and the behavioural scales that can be used to assess their level of consciousness. We will also discuss the difficulty to assess and detect remnant cognitive functioning in these patients.

[The Sensory Modality Assessment and Rehabilitation Technique (SMART): a behavioral assessment scale for disorders of consciousness]. / La Sensory Modality Assessment and Rehabilitation Technique (SMART) : une échelle comportementale d'évaluation et de revalidation pour des états altérés de conscience.

INTRODUCTION: Difficulties in detecting bedside signs of consciousness in non-communicative patients still lead to a high rate of misdiagnosis illustrating the need to employ standardized behavioral assessment scales. STATE OF ART: The Sensory Modality Assessment and Rehabilitation Technique (SMART) is a behavioral assessment scale of consciousness that assesses responses to multimodal sensory stimulation in disorders of consciousness. These stimulations can also be considered to have therapeutic value. PERSPECTIVES: We here review the different components and use of the SMART assessment and discuss its validity, reliability, and robustness in clinical practice. The scale has a high intra- and inter-observer reliability thanks to a detailed procedure description. However, in the absence of objective gold standards in the assessment of consciousness, it is currently difficult to make strong claims about its validity. A comparison between SMART and other standardized and validated coma-scales is proposed. CONCLUSION: In our view, SMART is an interesting tool for monitoring patients with altered states of consciousness subsequent to coma. Currently, we await studies on its concurrent validity as compared to other validated behavioral assessment scales and on the effect of SMART stimulations on patient outcome.

[Pain assessment in non-communicative patients]. / Mesurer la douleur chez le patient non communicant.

Pain is a subjective experience. Its assessment is based on the subject's direct verbal report. This method of assessment is, however, impossible in patients who cannot communicate their feelings. In this context, indirect measurements such as behavioral observations or physiological measurements are needed. To facilitate the assessment of pain in non-communicative patients, numerous standardized behavioral scales have been developed. The aim of this review is to discuss the main validated pain scales employed in end-stage dementia, newborn and preverbal children, and severely brain damaged patients with a disorder of consciousness such as coma, the vegetative state or the minimally conscious state.

[Behavioural assessment and functional neuro-imaing in vegetative state patients]. / Evaluation comportementale et par neuroimagerie fonctionnelle des patients en état végétatif.

Currently, there remains a high rate of misdiagnosis of the vegetative state. This should incite clinicians to use the most sensitive "coma scales" to detect signs of consciousness in these patients. The gold standard remains the Glasgow Coma Scale (GCS, Teasdale and Jennet, 1974), with the Glasgow Liège Scale (GLS, Born, 1988) adding standardized assessment of brainstem reflexes. New sensible behavioral assessment tools for use in the acute neurocritical care setting include the Full Outline of UnResponsiveness (FOUR, Wijdicks et al., 2005). The Coma Recovery Scale-Revised (CRS-R, Giacino and Kalmar, 2004) specifically tests the diagnostic criteria differentiating vegetative from minimally conscious patients. Detecting signs of consciousness also depends on the employed methodology. We showed that for the assesment of the presence of visual pursuit, using a moving mirror is better suited than using a moving object or person. The clinical diagnosis can be confirmed by cerebral positron emission tomography studies objectively quantifying residual metabolic activity in vegetative and minimally conscious patients. Ongoing studies evaluate the prognostic value of functional magnetic resonance imaging studies in these challenging patient populations.