What causes seizures, and how can we treat them? - Christopher E. Gaw

573,613 views ・ 2021-08-03

TED-Ed


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Nearly three millennia ago,
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a Babylonian tablet described a curious illness called miqtu.
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Said to cause symptoms ranging from facial twitching to full body convulsions,
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the Babylonians believed those afflicted were possessed by evil spirits,
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and the only treatment was divine intervention.
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Today, we know the symptoms of miqtu by another name,
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and modern medicine has developed numerous treatments
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for those experiencing seizures.
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But these ancient afflictions still hold a surprising number of secrets.
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Doctors define a seizure as any set of symptoms
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resulting from excess electrical activity in the brain.
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Outside this shared feature, there is a massive range of seizure symptoms,
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and researchers have identified a variety of different seizure types.
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But regardless of the underlying conditions that cause them,
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every seizure begins here.
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Hippocrates identified the brain as the source of seizures around 400 BCE.
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However, this insight didn't immediately lead to better treatments.
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Generally, ancient Greeks prescribed medicinal herbs and alterations in diet.
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If they believed the seizure was caused by bleeding in the skull,
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they sometimes employed a technique called trepanation.
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This early surgery involved drilling a hole in the skull to let blood escape
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and relieve pressure on the brain.
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Trepanation had... sizable risks.
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But it wasn’t until the 19th century that scientists would make
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the next leap forward in seizure treatment.
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In 1870, two German researchers discovered that using electricity
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to stimulate specific areas of a dog’s brain could move parts of its body.
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Around the same time, other scientists discovered the brain and nervous system
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were connected via a network of cells called neurons
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that transmitted electrical signals throughout the body.
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This established the brain as the control center for nerve impulses
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that determine our thoughts and movement.
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Better yet, this model made it clear that seizures were due to errors
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in that control center,
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such as misfiring neurons or excess electrical activity.
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Early experiments even suggested that different patterns of misfiring
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could account for different seizure types and symptoms.
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So if seizures were due to neurons misfiring,
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how could doctors stop this from happening?
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Physicians like Sir Charles Locock hypothesized that sedative drugs
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might calm overactive brain activity,
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a theory he confirmed by treating seizures
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with a medication called potassium bromide.
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Others like Sir Victor Horsley
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suspected that removing damaged parts of the brain might stop a patient's seizures.
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In 1886, he performed a craniotomy,
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temporarily removing part of a patient's skull to extract scarred brain tissue.
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Not only did his patient survive, but his seizures improved,
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launching further research in surgical treatments.
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Over the next two centuries, seizure treatments advanced rapidly.
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And today, there are dozens of available seizure medications
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that work with unprecedented specificity.
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Some newer medications are able to focus on specific proteins
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in the neuron to help manage electrical activity.
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And advanced brain imaging techniques can sometimes allow doctors to pinpoint
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exactly what parts of the brain are causing an individual's seizures.
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Surgeons then use this information to perform targeted surgeries.
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These various treatments help doctors manage the majority of seizure cases,
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allowing most people with seizures to live healthy and comfortable lives.
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But the underlying pathology of many seizures remains elusive.
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In cases without clear brain damage or certain types of pre-existing conditions,
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it's incredibly difficult to determine what causes neurons to misfire.
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It's also not always clear why some treatments are effective.
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And even more mysterious are cases where seizures are resistant
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to existing treatments that work on similar seizure types.
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Scientists are still working on these questions,
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but there are clear answers for what to do
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if you encounter someone experiencing a seizure.
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You should never hold a seizing person down,
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put objects in their mouth, or perform CPR.
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Instead, try to keep the person safe from falling or bumping their head,
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shift them onto their side to keep airways open,
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and stay with them until medical help arrives.
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