Prognostic Factors to Regain Consciousness

Due to continuous improvements in acute medical care, the number of patients surviving severe brain damage has increased over the past decades. While some patients improve significantly during the first days after the injury, other patients remain in altered states of consciousness (i.e. coma, unresponsive wakefulness syndrome or minimally conscious state). Acquired brain damage such as cerebrovascular diseases, traumatic brain injuries or hypoxic-ischemic encephalopathies are the main causes of severe impaired consciousness.The correct classification of the level of consciousness is of great importance, since the different states of consciousness are associated with different prognoses and treatment options. Patients who show minimal signs of consciousness (MCS) a month after the onset of the disease have better chances of regaining consciousness within one year than UWS patients. Within both categories (UWS, MCS), traumatic aetiologies in turn have a better prognosis than non-traumatic aetiologies. The prognosis usually begins with the admission of the patients to the intensive care unit of the acute care facility. But even in later treatment phases, a large number of patients regain consciousness, e.g. during post-acute early rehabilitation and even years after the disease. Numerous factors are associated with the prognosis (e.g. age, aetiology, duration of illness, functional status and state of consciousness). Although there are numerous studies on the prognostic factors and outcome of patients with severe brain damage, only a few have explicitly examined patients with initially severe and long-lasting impaired consciousness. The study therefore aims to identify factors that predict the medium and long-term outcome of patients with severe impaired consciousness in early neurological rehabilitation.

Over a period of 36 months, 130 patients undergoing neurological early rehabilitation with impaired consciousness are included. It is a prospective observational study that is carried out in a single neurological rehabilitation centre (monocentric). Different routine data, disease severity and functional status are documented for each patient. In addition, MRI, EEG and evoked potentials are measured within the first week. The level of consciousness is recorded with the Coma-Recovery-Scale-Revised and serves as the primary outcome parameter. Complications, comorbidities, functional status and leve of consciousness are assessed weekly. After eight weeks, the measurement of the MRI, the EEG and the evoked potentials are repeated. After 3, 6 and 12 months, the Glasgow Outcome Scale-Revised is used to follow up the current status of the patients.

Inclusion criteria

• early neurological rehabilitation (phase B)
• stroke, traumatic brain injury, hypoxic-ischemic encephalopathy
• disorder of consciousness (coma, UWS, MCS)
• at minimum two weeks after disease onset
• admission to intensive care unit
• written consent from the patient's legal representative
• exclusion of pregnancy

Exclusion criteria

• insufficient cardiorespiratory stability
• fractures or severe infratentorial brain injuries leading to impaired auditory evoked - potentials
• previous brain damage
• mental disorders (dementia, depression)
• colonization with multi-resistant pathogens
• MRI contraindications
• claustrophobia
• weight > 120 kg