Classifying Disorders of Consciousness: Past, Present, and Future

Abstract

With the advent of advanced analytical methods applied to functional neuroimaging and neurophysiological data, cerebral conditions have been defined that challenge the established classification of disorders of consciousness. A subset of brain-damaged patients has been identified who cannot carry out motor commands, but who exhibit patterns of cerebral activation during mental imagery tasks that are indistinguishable from those in healthy controls. This condition, termed "cognitive motor dissociation", has overturned many assumptions regarding the detection, diagnosis, prognosis, and care of patients with brain injury. Three factors are likely to influence efforts to improve the classification of disorders of consciousness in the near future: the types of data that will become available to characterize brain states, the modeling paradigms utilized for data analysis, and the ability to implement classification schemes in the clinical setting. Here we review past achievements, present states, and future projections for the classification of impaired consciousness and responsiveness.

Chronic Disorders of Consciousness: guidelines of the All-Russian public organization “Federation of Anesthesiologists and Reanimatologists”

“…Состояние минимального сознания (СМС) -это клиническое состояние, сопровождающееся тяжелым нарушением сознания, при котором тем не менее имеют место отчетливые, хотя и минимальные, часто нес тойкие признаки целенаправленного поведения, свидетельствующие об осознании пациентом собственной личности или окружаю щей действительности [1,2,4].…”

“…Выход из СМС [1,2] -это состояние, которое формируется по мере восстановления когнитивных функций, когда пациент отчетливо демонстрирует функционально значимое поведение, т. е. способен выполнять действия, позволяющие ему достаточно эффективно взаимодействовать с окружающим миром. Функционально значимое поведение включает в себя функциональную коммуникацию, которая может осуществляться с помощью устной или письменной речи, условных знаков, означающих «да» и «нет», или специальных устройств для облегчения общения, и целенаправленное (функциональное) использование предметов, т. е. наличие у пациента возможности отличать один предмет от другого и применять их в соответствии с их предназначением.…”

Functional MRI for Acute Covert Consciousness: Emerging Data and Implementation Case Series

“…The terminology describing the various types of covert brain activity fueling this transformation is shifting the definitions of DoC from pure behavior-based definitions to those incorporating the detectable brain states by advanced methods ( Table 1 ). 23 The utilization of newer terms may increase due to their potential to classify the highest DoC–brain state above that of behaviors seen on exam 34 and increase accuracy of outcome prediction. 1 Even more importantly, the detection of brain activity indicating potential for good outcome may lead to the development of targeted therapies, such as pharmacologic agents, brain stimulation, and brain–computer interfaces.…”

Clinical application of recommendations for neurobehavioral assessment in disorders of consciousness: an interdisciplinary approach

“…However, it has been found that passive paradigms have a greater likelihood of capturing preserved consciousness ( Kondziella et al, 2016 ; Aubinet et al, 2022 ). The scientific understanding of CMD is evolving, but current evidence suggests it is likely a distinct phenomenon separate from the DoC spectrum ( Kondziella and Stevens, 2022 ), more akin to a functionally locked-in syndrome. Evidence suggests those who are identified as CMD while in the ICU have an improved functional recovery as compared to those unresponsive patients who demonstrate no evidence of consciousness with advanced neuroimaging ( Edlow et al, 2017 , 2021 ).…”