Summary
Highlights
The speaker begins by posing the question of how we can know if another human being is conscious and aware. He differentiates between wakefulness, which is easily ascertainable by observing physical cues like open eyes or EEG signals, and awareness, which is far more challenging to confirm. He demonstrates that 'command following,' like raising an arm on instruction, is the most direct way for a person to prove their awareness.
The discussion shifts to patients in a vegetative state, who appear awake but do not respond to external stimuli, making it impossible to assess their awareness through traditional means. The speaker highlights a logical problem: if a conscious patient cannot respond, there is no way to know they are conscious. This sets the stage for the scientific approach to tackling this issue.
Adrian Owen explains how his team uses functional magnetic resonance imaging (fMRI) to detect consciousness in unresponsive patients. The technique relies on the brain activating similar regions when imagining an action as when performing it. He uses the example of imagining playing tennis, which consistently activates the premotor cortex.
In 2006, a breakthrough occurred with a patient in a vegetative state for five months. When asked to imagine playing tennis, her brain showed activation in the same area as healthy volunteers, indicating conscious awareness. A second task, imagining navigating her house, activated different, specific brain regions, further confirming her ability to follow commands mentally. This revealed that 17% of seemingly vegetative patients exhibited signs of consciousness.
The team developed a method of rudimentary communication: imagining playing tennis for 'yes' and navigating home for 'no'. This was successfully demonstrated with a healthy volunteer and then, crucially, with a patient who had been in a vegetative state for five years. This patient was able to answer biographical questions accurately, proving conscious awareness and a capacity for communication through directed thought.
Owen emphasizes that this method provides the only way some patients can communicate. He likens it to asking direct questions to a healthy individual; accurate responses prove consciousness. While currently limited to yes/no answers, this technique offers a vital avenue for understanding patients' internal states and potentially improving their quality of life. The talk concludes with a powerful anecdote from Kate Banbridge, a patient who recovered from a vegetative state, underscoring the critical need for yes/no communication methods.