Disorder of Consciousness, Minimally Conscious State, Unresponsive Wakefulness Syndrome
Conditions
Keywords
Disorders of Consciousness, Electroencephalography (EEG), Event-related potential (ERP), Coma Recovery Scale-Revised (CRS-R), Acquired Brain Injury, Critically ill patients, Neurological rehabilitation
Brief summary
This prospective observational study investigates whether electroencephalography (EEG) can improve the differentiation between unresponsive wakefulness syndrome (UWS) and minimally conscious state (MCS) in patients with severe acquired brain injury. The study further examines the association between EEG markers of auditory processing and long-term functional outcome at 12 months.
Detailed description
Accurate classification of disorders of consciousness remains challenging in neurological early rehabilitation. Behavioral assessment is the clinical standard, yet misclassification persists, particularly in patients with severe motor impairment or fluctuating arousal. Neurophysiological measures may provide complementary information beyond observable behavior. This study applies event-related potential (ERP) paradigms during bedside EEG recording to assess hierarchical levels of auditory processing in patients with disorders of consciousness in the subacute phase after brain injury. The paradigms are designed to detect neural responses reflecting basic auditory discrimination as well as higher-order cognitive processing. The primary objective is to determine the highest neurophysiologically detectable level of auditory processing and to examine whether it differs between clinically defined consciousness groups. Secondary objectives include evaluating the relationship between EEG-derived markers and standardized behavioral assessments, as well as assessing the prognostic value of EEG findings for functional outcome one year after admission. The study aims to clarify the diagnostic and prognostic relevance of EEG-based measures in routine neurorehabilitation settings.
Interventions
BEHAVIORALComa Recovery Scale-Revised (CRS-R)
The Coma Recovery Scale-Revised (CRS-R) is a standardized behavioral assessment instrument used to determine the level of consciousness in patients with severe brain injury. It comprises six subscales evaluating auditory, visual, motor, oromotor/verbal, communication, and arousal functions, with hierarchically structured items to identify the highest level of behavioral responsiveness.
BEHAVIORALElectroencephalography (EEG)
Electroencephalography (EEG) is a non-invasive neurophysiological method used to record spontaneous and stimulus-related electrical brain activity via scalp electrodes. In this study, bedside EEG recordings are performed using structured auditory stimulation paradigms designed to elicit event-related potentials (ERPs). These include hierarchical paradigms assessing different levels of auditory processing, ranging from basic sensory discrimination (e.g., mismatch negativity, MMN) to higher-order cognitive processing (e.g., N400 responses). EEG-derived ERP markers are analyzed to determine the highest detectable level of auditory processing and to evaluate their association with clinical diagnosis and long-term functional outcome.
Sponsors
BDH-Klinik Hessisch Oldendorf
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
No
Inclusion criteria
* Presence of a disorder of consciousness (Unresponsive Wakefulness Syndrome \[UWS\] or Minimally Conscious State \[MCS\]), classified using the Coma Recovery Scale-Revised (CRS-R) based on three assessments conducted on at least two separate days * Age between 18 and 80 years * Written informed consent provided by the patient's legal representative * Preserved brainstem auditory evoked potentials (BAEPs) on at least one side
Exclusion criteria
* Ongoing sedation at the time of EEG assessment * Current treatment with medications known to significantly affect cortical functional state, including barbiturates, neuroleptics (antipsychotics), antiepileptic drugs, benzodiazepines, or comparable agents * Colonization with multidrug-resistant organisms requiring isolation precautions (e.g., 4MRGN) * Pregnancy * Impaired language comprehension (e.g., insufficient German language proficiency or aphasia) * Temporal bone fractures or severe infratentorial brain injury associated with unilateral or bilateral absence of auditory evoked potentials (AEPs) * Bilateral hearing impairment or deafness, or presence of a cochlear implant * Scalp wounds or conditions preventing placement of an EEG electrode cap
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Highest Detectable Hierarchical Level of Auditory Processing | week 2-3 after admission to neurological rehabilitation | The primary endpoint is the highest neurophysiologically detectable hierarchical level of auditory processing, operationalized by the presence of significant auditory event-related potential (ERP) effects. For each ERP paradigm, analyses are conducted at the individual patient level to determine whether a statistically significant ERP effect is present within predefined time windows and electrode regions. The highest hierarchy level showing a significant effect defines the individual outcome (ordinal scale: levels 1-4). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Association Between Clinical Level of Consciousness and Neurophysiological Cognitive Processing | week 2-3 after admission to neurological rehabilitation | Relationship between clinically determined consciousness status (e.g., UWS vs. MCS) and the highest achieved hierarchical level of auditory processing as measured by ERP responses. |
| Prognostic Validity of ERP-Based Hierarchical Processing Level | 12 months after EEG measurement | Predictive value of the highest achieved hierarchical level of auditory processing for functional outcome at 12 months after admission. Functional status will be assessed using a standardized outcome measure. |
Countries
Germany
Outcome results
None listed