Research considerations for prospective studies of patients with coma and disorders of consciousness

Clinical Diagnostic and Prognostic Value of Residual Language Learning Ability in Patients with Disorders of Consciousness

Recent research suggests that the detection of preserved cognitive function can assist in the diagnosis and prognosis of patients with disorders of consciousness (DoC). This study investigates EEG signals as indicators of neural activity associated with the processing of transitional probabilities during a learning paradigm in patients with DoC. By examining the sensitivity to transitional probabilities across levels of consciousness, we aim to assess the potential value of this indicator in clinical diagnosis and prognosis. We collected EEG recordings from 51 DoC patients (10 female) and 26 healthy controls (9 female). EEG activity was recorded while participants listened to artificial vocabulary speech sequences before and after the learning phase. Intertrial phase coherence (ITPC) was used to examine differences in neural responses in different learning phases. Results showed that minimally conscious patients showed a significant increase in the word-tracking response after the learning phase, similar to healthy controls. Moreover, their learning-mediated word-rate ITPC difference correlated significantly with their Coma Recovery Scale-Revised score and 6 month outcome. However, these correlations were absent in unresponsive wakefulness syndrome patients. Crucially, differences in vocabulary ITPC before and after the learning phase effectively discriminated between healthy controls and patients, as well as between minimally conscious and unresponsive wakefulness syndrome patients. Combining EEG indicators with clinical performance accurately predicted patients' prognosis. In conclusion, the language learning paradigm has the potential to contribute to both diagnosis and prognosis in this challenging population, thereby significantly reducing prognostic uncertainty in medical decision-making and benefiting the rehabilitation of DoC patients.

Vegetative state in two Italian residential facilities: study of prognosis for subjects and related caregivers

BACKGROUND

Vegetative state (VS) is a severe disturbance of consciousness, often caused by cerebral insults, with limited long-term prognosis data.

STUDY OBJECTIVE

to provide a detailed picture of a cohort of patients treated at 2 long-term care facilities in Lombardy starting from 2014.

METHODS

Multicentric observational study. Subjects who met the diagnostic criteria for VS were admitted. A caregiver was identified for each patient and filled two questionnaires to evaluate quality of life (SF-36) and need for psychological support (FSQ-30).

RESULTS

The study included 146 patients (median age: 61.8 years at admission, 60.4 at the event that caused VS). Non-traumatic cerebral hemorrhage was the leading cause of VS (41%), followed by traumatic (19%) and anoxic brain injury (17%), and ischemic stroke (6.8%). The cumulative mortality was 10% at 1 year, 24% at 2 years, 43% at 5 years, 69% at 10 years, and 88% at 15 years after the event that caused VS, with age (HR 1.03) and ischemic stroke (HR 2.86) as risk factors. Among 24 caregivers, 50% had FSQ-30 score suggesting recommended psychological support (R area), 33% were in the SR area (strongly recommended), and 13% in the U area (urgent need). Females had worse FSQ-30 and SF-36 scores than males, particularly in the mental health index (median 60 vs. 74) and mental component scale (45.3 vs. 53.2).

CONCLUSIONS

Hemorrhages were found to be the most common cause of VS, differing from previous studies that identified trauma as the primary cause. Caregivers exhibited significant psychological distress.

Common Data Elements for Disorders of Consciousness: Recommendations from the Working Group on Outcomes and Endpoints

BACKGROUND

Clinical management of persons with disorders of consciousness (DoC) is dedicated largely to optimizing recovery. However, selecting a measure to evaluate the extent of recovery is challenging because few measures are designed to precisely assess the full range of potential outcomes, from prolonged DoC to return of preinjury functioning. Measures that are designed specifically to assess persons with DoC are often performance-based and only validated for in-person use. Moreover, there are no published recommendations addressing which outcome measures should be used to evaluate DoC recovery. The resulting inconsistency in the measures selected by individual investigators to assess outcome prevents comparison of results across DoC studies. The National Institute of Neurological Disorders and Stroke (NINDS) common data elements (CDEs) is an amalgamation of standardized variables and tools that are recommended for use in studies of neurologic diseases and injuries. The Neurocritical Care Society Curing Coma Campaign launched an initiative to develop CDEs specifically for DoC and invited our group to recommend CDE outcomes and endpoints for persons with DoCs.

METHODS

The Curing Coma Campaign Outcomes and Endpoints CDE Workgroup, consisting of experts in adult and pediatric neurocritical care, neurology, and neuroscience, used a previously established five-step process to identify and select candidate CDEs: (1) review of existing NINDS CDEs, (2) nomination and systematic vetting of new CDEs, (3) CDE classification, (4) iterative review and approval of panel recommendations, and (5) development of case report forms.

RESULTS

Among hundreds of existing NINDS outcome and endpoint CDE measures, we identified 20 for adults and 18 for children that can be used to assess the full range of recovery from coma. We also proposed 14 new outcome and endpoint CDE measures for adults and 5 for children.

CONCLUSIONS

The DoC outcome and endpoint CDEs are a starting point in the broader effort to standardize outcome evaluation of persons with DoC. The ultimate goal is to harmonize DoC studies and allow for more precise assessment of outcomes after severe brain injury or illness. An iterative approach is required to modify and adjust these outcome and endpoint CDEs as new evidence emerges.