Accurately determining the level of consciousness in patients with severe brain injury is essential for treatment planning, prognosis, and ethical decision-making. Clinically, levels of consciousness are differentiated into coma, Unresponsive Wakefulness Syndrome (UWS), and Minimally Conscious State (MCS) based on behavioral signs. Although behavioral assessment is considered the clinical gold standard, it is prone to misclassification. Research has shown that a substantial proportion of patients initially diagnosed with UWS may actually show signs of minimal consciousness, which is associated with better cognitive abilities and a more favorable prognosis.

The Coma Recovery Scale-Revised (CRS-R) is internationally recommended for diagnosing disorders of consciousness, but it is time-consuming and not free from diagnostic error. Repeated assessments can significantly improve diagnostic accuracy. To enhance feasibility in routine clinical practice, a shorter and more time-efficient assessment tool, the Simplified Evaluation of CONsciousness Disorders (SECONDs), was developed. This scale focuses on the behavioral signs most strongly associated with MCS and uses optimized testing procedures while maintaining high diagnostic accuracy.

The aim of this study is to further evaluate diagnostic approaches for assessing consciousness in patients with severe brain injury and to improve the reliability and clinical applicability of these assessments.

This prospective observational study is designed to evaluate the clinical utility and diagnostic performance of the Simplified Evaluation of CONsciousness Disorders (SECONDs) in a neurological rehabilitation setting. The study aims to assess whether the implementation of SECONDs improves diagnostic accuracy in patients with disorders of consciousness during the subacute phase after severe acquired brain injury.

Participants will undergo structured behavioral assessment using SECONDs as part of the study protocol. Diagnostic classifications derived from SECONDs will be analyzed with regard to their internal consistency and clinical plausibility within the rehabilitation context.

To examine prognostic validity, functional outcome will be assessed 12 months after the initial evaluation. Follow-up data will be collected through structured telephone interviews with relatives or legal representatives. Functional status will be systematically documented in order to determine the predictive value of SECONDs classifications for long-term clinically relevant outcomes.

The study seeks to contribute to optimizing diagnostic procedures in disorders of consciousness and to strengthen the evidence base for time-efficient behavioral assessment tools in routine neurorehabilitation practice.

Inclusion Criteria:

• Admission to an intensive care unit (ICU) or intermediate/high-dependency care unit
• Underlying etiology of brain injury: anoxic, traumatic, or vascular
• Time since index event < 90 days
• Early Rehabilitation Barthel Index (ERBI) score < 30 points

Exclusion Criteria:

• History of prior brain injury
• Pre-existing major psychiatric disorder
• Impaired language comprehension (e.g., insufficient German language proficiency or aphasia)
• Ongoing sedation at the time of assessment
• Interruption of rehabilitation treatment (transfer to an acute care hospital) for more than 14 days
• isolation precautions due to multidrug-resistant organisms

The study population consists of adult patients with severe acquired brain injury admitted to a neurological early rehabilitation program. Eligible participants present with a disorder of consciousness in the subacute phase (within 90 days after the index event) and require intensive or monitored medical care. Underlying etiologies include anoxic, traumatic, or vascular brain injury. Patients are characterized by severe functional impairment, as reflected by a low Early Rehabilitation Barthel Index score at admission.