A recent paper in the New England Journal of Medicine detected consciousness in a quarter of the 241 unresponsive patients with brain injury who were tested with fMRI and EEG brain scans:

During these tests, participants heard instructions, such as “imagine opening and closing your hand” followed, 15-30 seconds later by “stop imagining opening and closing your hand.” The fMRI and EEG brain responses showed that 60 (25 percent) of participants repeatedly followed this instruction covertly over minutes.

Mass General Brigham. “International study detects consciousness in unresponsive patients.” ScienceDaily, 14 August 2024.

“Covertly” means that the patients were not able to respond directly but brain activity showed that they understood what was asked of them.

The number was higher than expected and raises both questions and hope for comatose patients. The journal article notes,

The percentage of participants with cognitive motor dissociation is 5 to 10 percentage points higher in our study than in previous studies.3,6,9–11 This finding may be due to our multimodal approach, which classified the participants who underwent assessment with both techniques on the basis of responses on either fMRI or EEG. The percentage of participants with cognitive motor dissociation may have been even higher if all the participants had been assessed with both imaging techniques.

Bodien YG, Allanson J, Cardone P, Bonhomme A, et al., Cognitive Motor Dissociation in “Disorders of Consciousness.” N Engl J Med. 2024 Aug 15;391(7):598-608. doi: 10.1056/NEJMoa2400645. PMID: 39141852.

In short, when the researchers investigated the matter systematically, they found more cases (and might find still more later). This level of investigation, which is probably not routine, may make a considerable difference to patient assessment and care:

Just knowing that somebody is cognitively aware and more capable than is immediately apparent, can alter their clinical care substantially. “Families have told us that once a positive test result revealing cognitive motor dissociation is shared with the patients’ clinical team, it can change the way that the team interacts with their loved one,” [Yelena] Bodien said. “Suddenly, the team is paying more attention to subtle behavioral signs that could be under volitional control, or speaking to the patient, or playing music in the room. On the other hand, failing to detect cognitive motor dissociation can have serious consequences, including premature withdrawal of life support, missed signs of awareness, and lack of access to intensive rehabilitation.”

Mass General Brigham. “In unresponsive patients”

How advanced technologies might help them communicate

A finding that a comatose patient is aware but cannot communicate in usual ways raises the possibility of using new communication technologies. As Julian Nowogrodzki notes at Nature:

The results mean that a substantial number of people with brain injuries who seem unresponsive can hear things going on around them and might even be able to use brain–computer interfaces (BCIs) to communicate, says study leader Nicholas Schiff, a neurologist at Weill Cornell Medicine in New York City. BCIs are devices implanted into a person’s head that capture brain activity, decode it and translate it into commands that can, for instance, move a computer cursor.

“One-quarter of unresponsive people with brain injuries are conscious,” August 14, 2024

The Neuralink connection

Brain–computer interfaces are the technology that Elon Musk‘s Neuralink is pioneering. The research firm currently aims to address paralysis, blindness, and limb loss but its technology may be applicable to persons who are unresponsive due to brain injuries. It was tried earlier this year on Noland Arbaugh:

There was a setback (described in the video), but Arbaugh and Neuralink are hanging in so far, treating it as a learning experience.

But, circling back to comatose patients: making contact with those who can communicate in principle, if only via brain scanning technology, is a first step toward treatment of what were once deemed hopeless cases.

Here’s more on the technology of BCI:

And its history:

You may also wish to read: Will Neuralink’s brain implant help paralysis victims? Addressing disabilities like paralysis, limb loss, and blindness seems a more realistic goal than the hyped (and feared) human–machine hybrids. When Elon Musk announced his first implant recipient late last month, a broad public first learned that many people with disabilities use implants now.