Broca’s aphasia is a language disorder resulting from damage to the frontal lobe, leaving patients unable to articulate intended words. Current treatments involve speech therapy, but Northwestern University scientists are exploring a novel approach using brain-computer interfaces (BCI) to convert brain signals into spoken words.
For BCIs to be effective in treating Broca’s aphasia, it is crucial to identify where in the brain these devices should record signals. Traditionally used for patients with paralysis due to ALS or stroke, BCIs record from the frontal lobe. However, as Broca’s aphasia results from damage in this area, scientists need to look elsewhere in the brain.
A new study by Northwestern Medicine researchers has identified regions outside the frontal lobe—specifically in the temporal and parietal cortices—that are involved in speech intent. This discovery paves the way for potential BCI applications for Broca’s aphasia.
“This is a small, but necessary step,” said Dr. Marc Slutzky of Northwestern University Feinberg School of Medicine. “We showed that these non-frontal areas indeed contain information about someone’s intent to produce speech that allowed us to distinguish when they were going to speak versus when they’re not speaking or are just thinking about something that they don’t want to say out loud.”
The findings will be published on February 13 in the Journal of Neural Engineering and may help design BCIs that differentiate between language production and perception.
“It is critical not to be decoding the user’s thoughts that are not intended to be spoken aloud, both for practical reasons and ethical problems this could incur,” Slutzky added.
This study was conducted with patients without language deficits at Northwestern Memorial Hospital. Researchers recorded electrical signals from nine patients with epilepsy or brain tumors during seizure monitoring or awake surgery using electrocorticography (ECoG). Participants either read words aloud or remained silent while their brain activity was recorded.
Future research aims at decoding what participants actually said based on these recordings. The study titled “Decoding speech intent from non-frontal cortical areas” includes contributions from several authors at Northwestern University.
Funding for this research came from multiple grants provided by institutions such as the National Institute of Neurological Disorders and Stroke of NIH and other foundations.