The minimally conscious state: an analysis of current clinical trials registered in ClinicalTrials.gov

Abstract

The minimally conscious state (MCS) is a disorder of consciousness described in recent years for patients who have behavioral responses to stimuli that do not meet the classification of chronic vegetative state (CVS) or coma. This distinction is valuable in clinical practice, as minimally conscious patients may require different treatments and may have different long-term outcomes when compared to vegetative states or coma. In this report, we analyzed the ClinicalTrials.gov database to systematically assess all clinical trials regarding MCS. The database was queried using the term “minimally conscious state” in the “condition or disease” search parameter. Of the studies identified, those that had suspended, terminated, or otherwise unknown statuses were excluded. In total, 41 studies were analyzed. The included studies were initiated between 2008 and 2020, with the majority (63%) beginning in 2015 or later. Of the primary intervention modalities included, 15 (37%) evaluated stimulation modalities such as transcranial magnetic stimulation, transcranial direct current stimulation, implantable neurostimulation, vagus nerve stimulation, focused ultrasound and median nerve stimulation. Additionally, 5 (12%) used some form of behavioral therapy. A total of 4 (10%) studies involved pharmaceutical intervention, including dopamine agonists, analgesics and sedatives. Finally, 4 (10%) studies sought to determine the validity of current diagnostic methods and systems used to assess the status of patients in MCSs. Since the definition and criteria for CVS and MCS have been established, these two conditions remain closely associated despite evidence of different patient outcomes and treatment options. Many clinical trials are underway assessing interventions with stimulation. However, the trials are lacking with respect to diagnostic methods and pharmaceutical treatment.