Listening to the Brain When the Body Cannot Speak

Researchers have combined brainwave-imaging technology with language-based tests to see conscious brain activity among people who are unable to communicate in typical ways, giving doctors the information needed to provide critical health care interventions to these patients.

McMaster Researcher


Connolly, J.F. (2012) “Communicating with the Non- communicative: Assessing the Mental Life of Non-verbal Individuals Using Neurophysiological Techniques”. In Ojima, S., Otsu, Y., Connolly, J. F. & Thierry, G. (eds.), Future Trends in the Biology of Language, pp.153-72, Keio University Press.

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What is this research about?

Some health conditions prevent people from being able to use their bodies to respond to routine medical tests for consciousness. “Consciousness” is defined in health science as brain activity linked to a level of awareness needed to live and function as a human being. People in a coma or suffering from traumatic brain injury or stroke may be wrongly diagnosed by doctors as being in a vegetative state (“brain dead”) without a possible chance for recovery, and may not receive the life-saving interventions needed to rehabilitate them. In a similar manner, individuals living with nonverbal autism may be diagnosed as “low functioning” simply because they are unable to respond verbally or do not perform in normal ways to standard tests. Dr. John Connolly, Senator William McMaster Chair in the Cognitive Neuroscience of Language, has spent over two decades developing and fine-tuning methods to detect conscious brain activity in people who have suffered brain injury or live with conditions that severely limit their speech or gesturing ability.

What did the researchers do?

Connolly recognized that capacity in communication-impaired populations could only be properly assessed when some type of communication link with the patient was created. Capturing brain signals using the technology of EEG (electroencephalogram), he was able to identify human brain activities that consistently happen in response to particular language patterns. Through testing many groups of people in tightly controlled experimental settings, massive amounts of data were collected and analysed. Connolly was able to use these data to address issues which, until relatively recently, had limited the broad application of cognitive language research using neuroscience methods in clinical contexts.

What did the researchers find?

Connolly’s research has provided a window in the mental life of people who cannot speak for themselves. New techniques developed by Connolly and colleagues have established a reliable test for assessing patients in hospitals and other controlled settings who are afflicted by disorders of consciousness. The method demonstrates that simple language-based tests recorded and read by a computer to a nonverbal person will produce reliable brainwave patterns if the person understands what is being said to them. Signs of language comprehension also signal the presence of consciousness. The research provides evidence to support the theory that language serves as the basis for consciousness as well as showing how specific language structures trigger conscious response. This research has been conducted in health care settings to provide health care professionals with better information about the state of consciousness of patients who may have an active mental life that is not evident if they are assessed solely on the basis of their observable behaviour. 
Connolly’s work demonstrates the value of conducting such tests in clinical settings so that patients can obtain the right health care treatments when they need them most. Patients who were previously at risk of being misdiagnosed as in a vegetative state or low functioning using conventional measures may now have these diagnoses corrected through the use of relatively inexpensive technology grounded in the latest research evidence. The door has opened for these individuals and their families to obtain appropriate health care interventions that have been shown to speed improvement and recovery.

How can you use this research?

Patient advocacy organizations engaged with health policymakers, such as Autism Speaks, have shown keen interest in this research. Connolly has also worked with individual families and caregivers as well as health care providers in clinical settings. Mapping how the human brain works in response to language allows all of us, including neuroscientists and linguists, to marvel at the brain’s ability to develop and retain the means for language processing when other parts of the body typically used for human communication don’t work. This research reminds us that the human mind is one of the most complex and important puzzles facing researchers, and one about which we are gaining more knowledge every day. Understanding how the mind is intertwined with our ideas of what makes us human can help us to empathize with and advocate for those who have difficulty communicating with their bodies.

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Research Impacts

Global News 16x9 coverage

March 23, 2013

Global News dedicated a show to covering brain function in patients with consciousness disorders, as well as Dr. Connolly's work in this field.

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