ILLUSTRATES Andre Santos
QUESTION Jadiel de Souza, Palmas, TO
No. The comatose patient has an important neurological organ “turned off”: the ascending reticular activating system (abbreviated SARA). This structure of neurons in the brainstem regulates sleep and wake states (and therefore coma). But it is also a “communication center” with the thalamus, which transmits sensory impulses. If it is not working, the stimuli captured by the eyes do not reach the part of the brain that interprets them. It’s as if the bridge that connects the senses and the mind has collapsed.
Talk to her
In theory, the comatose brain cannot interpret sounds either. However, some research has proven that hearing the voice of relatives can help with treatment. This was the case with the guinea pigs analyzed by Northwestern University in the USA: those who listened to personal stories recorded by relatives up to six times a day regained consciousness faster
What the eyes don’t see…
Most of the coma victim’s vital functions continue to run smoothly. That’s why, for example, they continue to eliminate feces and urine. The eyes are no exception: all structures continue to work. But the nerve signals they send cannot reach the areas of the brain that interpret them, such as the occipital cortex.
Juliana is passed out
During a faint, it is also not possible to see. The “blackout” is caused by some temporary problem in the distribution of blood in the brain. Among other things, this blocks the interpretation of stimuli received by the eyes. Therefore, it is also common for the fainted to report that, shortly before, he felt blurred vision (or with many lights)
15 shades of gray
To determine someone’s level of consciousness, medicine uses the so-called Glasgow scale. Ocular response, motor response, and verbal response tests are converted into a score ranging from 3 (deep coma) to 15 (mild trauma). Based on this numerical result, the doctor decides, for example, whether it is necessary to submit the patient to mechanical oxygenation
READ MORE
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What happens in our body when we pass out?
Is it true that lighter eyes are more sensitive to light?
How many megapixels is the human eye?
CONSULTANCY Gisele Sampaio Silva, neurologist at Albert Einstein Hospital (São Paulo)
SOURCES Websites abc.med.br, infoschool It is Northwestern University