Science has advanced the quest to decode speech directly from the brain

Stroke can rob patients of the ability to speak. A step forward has been taken to restore communication for these individuals.

Sep 9, 2019 |
3 min read

Many of us take the ability to speak for granted. We rely on verbalizations to express our wants and needs.

We can ask for more warmth when the temperature drops. We can discuss what we’d like to eat when we’re hungry. We can beg and plead for somebody to turn off the radio when it plays a new Nickelback single.

Sadly, some people are robbed of this ability. Stroke and pulmonary embolisms are the most common explanations for this. Now, science has taken a step forward in the treatment of such issues. There’s a long way to go, but we’re closer to deciphering brainwaves and converting them to artificial speech.


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Why do stroke patients lose the ability to speak?

When somebody suffers a stroke, the flow of blood to the brain is compromised. Arteries clogging (known as ischemic stroke) or bursting (hemorrhagic stroke) are to blame for this.

The upshot is the same in either case. Blood cannot flow to the brain. This, in turn, kills brain cells. If the stroke attacks the left hemisphere of the brain, these cells are linked to the ability to speak. Sometimes, motor function is also compromised.

With intense therapy, some degree of communication can be restored – assuming the damage is not too severe. This is expensive and time-consuming, though. Time and money are commodities that some stroke patients lack. This can lead to a lifetime of compromised speech. In some cases, the patients are rendered mute.

Even if the patient can speak, it will be an arduous process. Also, they’ll find it difficult to articulate their words. A stroke patient may be asking somebody to pass them a pen. This will, frequently, come out as, “please pass me the potato” or something equally unhelpful.

As you can imagine, this is extremely frustrating for the individual. A stroke survivor already has enough to deal with. They don’t need any extra complications in their lives, and an inability to articulate their thoughts can be hugely stressful. This is why this breakthrough in neural decoding, published in the journal Nature, is so welcome.

What is neural decoding?

When we speak, it’s rarely a conscious effort. We’re not talking about people that and speak before thinking, here. Having a metaphorical foot in your mouth is a social issue, not a medical one.

When we speak, it’s a natural process. Our brain formulates thoughts and sends messages to the vocal cords. These cords then express our thoughts verbally through a series of vibrations. It’s rarely an active choice.

Neural decoding aims to cut out the middleman of vocal cords. It’s not mind-reading technology, and it’s very early days. Don’t expect a stroke patient to recite a Shakespearean sonnet using neural decoding. What will happen is that a computer can pick up on thoughts, and express at least some of the words into verbalizations.

Experiments on neural decoding were run on a focus group. It was found that, when given 25 different words, people could decipher the correct word almost half the time. This ratio dropped to nearly a quarter when the word count was upped to 50.

That may not sound like much, but for somebody that cannot speak at all, it’s a huge step forward. Having access to a handful of keywords can be a building block to greater understanding.

Besides, it’s still a better hit ratio than Siri. At least these patients will not be provided directions to the nearest Laundromat when asking for a teaspoon.

Will neural decoding help people that have never been able to speak?

Patients that have never been able to verbally articulate themselves are a different matter. Sadly, neural decoding will not aid people that live with cerebral palsy. Such individuals have limited-to-zero experience in using their vocal cords.

Like all scientific breakthroughs, though, patience is key here. Rome was not built in a day, after all. If neural decoding becomes everyday and helps stroke patients recover speech, who is to say that it cannot somebody help other patients discover the ability to talk?

Keep an eye on these developments. Happy accidents occur in science every day, as do, “eureka!” moments. Neural decoding is already taking sizeable steps forward. These may become giant strides in no time at all.

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