- testing language development in infants;
- determining the level of brain function in patients who are in a reduced state of consciousness, such as a coma;
- confirming that a person in a particularly critical job has understood the instructions they have received (e.g., an air traffic controller or a soldier);
- testing for the onset of dementia in older people based on their ability to follow a conversation.
Science & Technology
Brain signal indicates when you understand what you’ve been told
University of Rochester professor Edmund Lalor, along with colleagues at Trinity College in Dublin, Ireland, has developed a new method for using relatively inexpensive EEG scalp readings to assess how well people understand what they are hearing. In one experiment, researchers used just the electrical activity on the scalp's surface to compare brain signals while subjects listened to Hemingway's Old Man and the Sea played forwards and then backwards. (University of Rochester photo / courtesy Edmund Lalor)
During everyday interactions, people routinely speak at rates of 120 to 200 words per minute. For a listener to understand speech at these rates – and not lose track of the conversation – the brain must comprehend the meaning of each of these words very rapidly.
“That we can do this so easily is an amazing feat of the human brain – especially given that the meaning of words can vary greatly depending on the context,” says Edmund Lalor, associate professor of biomedical engineering and neuroscience at the University of Rochester and Trinity College Dublin. “For example, ‘I saw a bat flying overhead last night’ versus ‘the baseball player hit a home run with his favorite bat.’”
Now, researchers in Lalor’s lab have identified a brain signal that indicates whether a person is indeed comprehending what others are saying – and have shown they can track the signal using relatively inexpensive EEG (electroencephalography) readings taken on a person’s scalp.
This could have a number of “potentially significant” applications, Lalor says. They include: