Shadowing Practice: What is Narcolepsy? - Learn English Speaking with Video

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And how to kind of try to describe it to them.

I found over time it's really difficult for people to understand it.

It's just very complicated with this tiredness, the cataplexy, the fragmented sleep at night.

If you're a normal person, you've got sleep and you've got your waking life.

And occasionally they'll overlap a little bit.

For me, I live in this world that is very rarely am I fully awake and very rarely am I fully asleep.

I live in the in-between.

I'm Tom Scanlon.

I'm a professor of neurology at Harvard Medical School.

Narcolepsy is a neurologic disorder.

It is one of the most common sleep disorders.

It affects about one in two thousand people.

It doesn't matter how much sleep they get at night, they're going to feel sleepy every day.

People also can have a variety of other symptoms.

These include hypnagogic hallucinations, where they can have very vivid dreamlike hallucinations just as they're drifting off to sleep

or just when they awaken.

They can have something called sleep paralysis, where as they're falling asleep or sometimes when they wake up, they can't move.

And then there's cataplexy, which is similar to sleep paralysis.

The distinction is that cataplexy occurs right in the middle of the day, and it's triggered by strong emotions.

And then the last thing, which is perhaps sort of one of the strangest of all,

is that, considering that somebody with narcolepsy is often very sleepy through the day, they often have fragmented sleep at night.

They can wake up four or five times for 10 or 20 minutes for no clear reason.

And so in the same way that they have trouble maintaining wakefulness through the day, they they can have trouble maintaining sleep through the night.

Somewhere between age 10 and age 20 or so is when narcolepsy begins.

People usually start off with sleepiness and then the other symptoms follow.

So there's a number of different systems in the brain that are involved in promoting arousal or wakefulness and sleep.

Up here is the cortex.

This is the front near the forehead.

Here's the back.

This is the brainstem coming down here.

And this is the cerebellum, which is involved in balance.

The brainstem is the site that most of these arousal promoting signals come from.

And those cells send connections up throughout the whole front part of the brain,

and they help turn on the cortex and other parts of the brain when you're awake.

There's also some cells in a small region called the hypothalamus

that are involved in promoting sleep

and these sleep promoting cells one of the things they do is they actually turn off the wake promoting cells

and so that allows you to be fully asleep without any hint of consciousness.

This is called the mammillary body and just above it right here is where the hypocretin neurons sit.

And this is a really critical collection of neurons,

brain cells, that makes very particular and special neurotransmitters known as hypocretin or orexin.

Those are just two names for the same thing.

The hypocretin producing cells help activate and sustain activity in the other weight promoting brain regions across the day.

The brain contains billions of neurons and And only a very, very small number of these produce hypocretin.

It's probably somewhere between 100,000 and 200,000, which sounds like a large number, but when you compare it to 10 billion neurons, it's really very small.

In narcolepsy, those hypocretin-producing cells die off.

When you look closely at the brain of somebody who has narcolepsy, what you see is about a 90 to 95% loss of the hypocretin-producing neurons.

So there's two broad themes that are being pursued in narcolepsy research right now.

One theme is to understand what goes wrong in the brain when the hypocretin-producing cells die off.

How does that lead to sleepiness and cataplexing and other symptoms?

Another big theme is trying to understand what actually kills the hypocretin neurons in the first place.

Because if we could understand that, then it's possible that if one could diagnose and recognize narcolepsy right at the earliest stages,

we might be able to get in and stop that process.

As we've discovered more and more about what's actually causing the hypocretin neurons to die off,

and as we've discovered more about the consequences of that for the brain,

it's really given us a lot of hope for new opportunities for coming up with better therapies for people with narcolepsy.

If we could get hypocretin back in the brain somehow, that would be potentially as great is giving insulin to people with diabetes.

It would really be the missing factor coming back into play.

And it could, in theory, cure their sleepiness and cure their cataplexy in the most thorough fashion.

Right now, scientists are working with a variety of techniques to try to get hypocretin signaling back into the brain.

But the hope is that in 5, 10, or 15 years, we may see those hypocretin replacement therapies coming into clinical practice.

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Vocabulary and speaking notes for this lesson

This speaking lesson is built on the video “What is Narcolepsy?”. The speaker keeps coming back to these words: hypocretin, sleep, brain, narcolepsy, cells. This video has 61 sentences and 843 words to shadow. The speech runs for 4:59. The speaker talks at a natural 169 words per minute, close to everyday conversation. 83% of the words are among the 3,000 most common in English; the rest is worth studying before you start.

Key vocabulary in this video

15 words from the video worth learning, with pronunciation and meaning:

Word	Pronunciation	Meaning
asleep adjective	/əˈsliːp/	In a state of sleep; also, broadly, resting.
symptom noun	/ˈsɪm(p)təm/	A perceived change in some function, sensation or appearance of a person that indicates a disease or disorder, such as fever, headache or rash; strictly, a…
rarely adverb	/ˈɹɛəɹli/	Not occurring at a regular interval; seldom; not often.
discover verb	/dɪˈskʌvə/	To find or learn something for the first time.
cure verb	/kjɔː/	To restore to health.
disorder noun	/dɪsˈɔɹdɚ/	Absence of order; state of not being arranged in an orderly manner.
awake verb	/əˈweɪk/	To become conscious after having slept.
sleepy adjective	/ˈsliːpi/	Tired; feeling the need for sleep.
cortex noun	/ˈkɔɹtɛks/	The outer layer of an internal organ or body structure, such as the kidney or the brain.
fragment noun	/ˈfɹæɡmənt/	A part broken off; a small, detached portion; an imperfect part, either physically or not.
complicated adjective	/ˈkɑm.plɪˌkeɪ.tɪd/	Difficult or convoluted.
occur verb	/əˈkɜː/	To happen or take place.
technique noun	/tɛkˈniːk/	The practical aspects of a given art, occupation etc.; formal requirements.
compare verb	/kəmˈpɛɚ/	To assess the similarities and differences between two or more things [“to compare X with Y”]. Having made the comparison of X with Y, one might have found it…
replacement noun	/ɹɪˈpleɪsmənt/	A person or thing that takes the place of another; a substitute.

Phrasal verbs you will hear

Word	Pronunciation	Meaning
die off verb		To suffer a series of deaths; to die one by one; to progressively become extinct. (If a group of plants, animals, or people dies off, the entire group dies…
wake up verb	/ˌweɪk ˈʌp/	To stop sleeping; to awake.
come down verb		To descend, fall down, collapse.
come up with verb		To manage to produce, deliver, or present (something) by inventing, creating, thinking of, or obtaining it.
turn off verb		To power down, to switch off, to put out of operation, to deactivate (an appliance, light, mechanism, functionality etc.).

Grammar in this video

The structures the speaker uses most, with the exact words from the video:

Structure	In the video
Passive voice be + past participle — the focus is on what happens, not who does it	are involved · is involved · is called
Relative clauses who / which + clause — extra information about a person or thing	cataplexy, which is · thing, which is · cerebellum, which is
Present perfect have/has + past participle — a past action that still matters now	have fragmented · we've discovered

Pronunciation to watch

The speaker uses 14 contractions and reduced forms, such as they're, I'm, we've. Say them the short way, as you hear them.

The “sh” and “zh” sounds: occasionally /əˈkeɪʒənəli/, potentially /pəˈtɛnʃ(ə)li/, emotion /ɪˈməʊ.ʃən/, consciousness /ˈkɑnʃəsnəs/, distinction /dɪˈstɪŋkʃən/
Long words — get the stress right: complicated /ˈkɑm.plɪˌkeɪ.tɪd/, occasionally /əˈkeɪʒənəli/, potentially /pəˈtɛnʃ(ə)li/, neurological /nɝəˈlɑd͡ʒɪkəl/, hypocretin /ˌhaɪ.poʊˈkɹiː.tən/

How to practise with this video

Listen to the whole video once without speaking and note the words you do not know.
Start at 0.75× speed, shadow it sentence by sentence, then go back to normal speed once it feels easy.
Record yourself and compare with the original, paying attention to words like asleep, symptom, rarely.

What is the Shadowing Technique?

Shadowing is a science-backed language learning technique originally developed for professional interpreter training and popularized by polyglot Dr. Alexander Arguelles. The method is simple but powerful: you listen to native English audio and immediately repeat it out loud — like a shadow following the speaker with just a 1–2 second delay. Unlike passive listening or grammar drills, shadowing forces your brain and mouth muscles to simultaneously process and reproduce real speech patterns. Research shows it significantly improves pronunciation accuracy, intonation, rhythm, connected speech, listening comprehension, and speaking fluency — making it one of the most effective methods for IELTS Speaking preparation and real-world English communication.

Shadowing technique: read the full step-by-step guide →

Shadowing Practice: What is Narcolepsy? - Learn English Speaking with Video

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