New research conducted by experts at Mass General Brigham has found that brain scans, such as fMRI and EEG, can detect consciousness in some patients with severe brain injury who appear unresponsive. The study involved 241 participants who did not respond to simple instructions, and it revealed that 25 percent of these individuals showed brain activity suggesting cognitive motor dissociation. This phenomenon indicates that these patients understand, remember, and can attend to instructions, despite their lack of visible response. The researchers emphasized the importance of detecting and harnessing this unseen cognitive capacity to improve communication and promote further recovery in these patients.
Patients with severe brain injury may experience disorders of consciousness, including coma, a vegetative state, or minimally conscious state. The study found that cognitive motor dissociation was most common in participants assessed with both fMRI and EEG, suggesting that multiple tests using different approaches may be necessary to ensure consciousness is not missed. The data for this study were collected over 15 years from six different sites across the US, UK, and Europe. The study highlighted the need for more standardized testing methods and the development of approaches to systematically assess unresponsive patients to improve detection of cognitive motor dissociation and support for patients and their families.
The research also included data from 112 participants who did respond to simple instructions at the bedside, but in 62 percent of these cases, brain responses suggestive of covertly following instructions were not detected during fMRI and EEG tests. This finding underscores the complexity of these tests and the high-level thinking skills required to perform them. The study’s authors noted that failing to detect cognitive motor dissociation can have serious consequences, including premature withdrawal of life support and missed signs of awareness. Conversely, knowing that a patient is cognitively aware can significantly alter their clinical care and the way clinical teams interact with them.
The study contributes to the growing body of research on cognitive motor dissociation in patients with severe brain injury and highlights the ethical and clinical implications of identifying this condition. The researchers emphasized the need for systematic medical research, technology development, and better clinical infrastructure to benefit patients with disorders of consciousness. The data from this study may also lead to further research on interventions to facilitate effective communication with these patients, including the use of brain-computer interfaces. As the field continues to progress, efforts to validate tools and develop standardized approaches for assessing unresponsive patients will be crucial for improving detection of cognitive motor dissociation and providing appropriate support to patients and their families.