Hawking’s Spelling Device and P300

Nov 3, 2018 · 5 min read

Stephen Hawking, one of the most revered scientists of our era, suffered from Amyotrophic Lateral Sclerosis (ALS). ALS is a neurodegenerative disease that mainly involves motor neurons responsible for voluntary muscle movement. The disease is progressive, meaning that it gets worse over time. There’s no cure for ALS, nor a method to halt, slow, or reverse the progression.

People suffering from ALS or similar debilitating conditions which disable the ability to “communicate”, need to use certain ‘helper’’ tools in order to be able communicate with the outside world. These devices usually gather some form of data from the user’s body, analyze it, and utilize the findings through a specific software in order to accomplish their task s — which are mostly generating sound or text. It is not an easy job to come up with a user-friendly device for people who have nearly zero voluntary control over their bodies, yet Hawking’s spelling device is a prime example and a great product in this category.

Although not in a comfortable way, Hawking was able to move his hands and talk when he was younger. As time passed, his condition got worse, culminating in further loss of neurons and voluntary muscle control. As Hawking gradually lost the ability to speak or even move his hands to control his wheelchair, he needed a new method for daily communication as well as to speak his brilliant mind that would give birth to countless articles, books and lectures. This was the time when technology gave a helping hand to Hawking!

From 1997 and onwards, Intel developed Hawking’s spelling device. Hawking’s control over his computer was made possible via an open sourced software called ACAT. This software displayed letters, numbers, shortcuts, and had a cursor iterating through them all the time. Whenever Hawking wanted to *click* on one of the options, he contracted a muscle located under his eye to register the action. Through this method, even if it was a slow and hard process, Hawking was able to communicate with the outside world.

Later with help of the mobile keyboard software company SwiftKey, Hawking’s device was upgraded. The programmers scanned every book and article Hawking had ever written, and created a “word prediction and completion” system which turned out to be very effective. Overall, if Hawking ever said “Black”, there was a huge probability that the second word he’d choose would be “Hole”, and the software was successful at predicting it. Hawking once mentioned that he just needed to type two letters on average to type a complete word. Later on, the software became even more capable, enabling Hawking to navigate his files, surf the web, reply to his mails and so on.

All those improvements over the software and the device made it an accessible tool for everyone suffering from similar medical conditions.

P300 Spelling Devices

P300 is an event related brain potential that is linked to the human decision making process. A person’s reaction to an input can be interpreted using EEG by this brain potential. P300 is mostly utilized with the Oddball paradigm where subjects are asked to expect one rare event within many irrelevant events. When the subject receives the input which is told relevant to him, then the P3 response can be seen on the EEG. P300 is the short form for “Post 300 milliseconds” which indicates that this potential peaks at 300 milliseconds after the event.

Since 1980, P300 has been applied to many fields for many use-case scenarios. One example would be lie detectors. P300 have been proposed for guilty knowledge tests. The big thing of P300, for us, is its potential for brain-computer interfaces. There are already numerous researches being conducted in utilizing P300 for spelling out letters without ever moving a single muscle. It’s possible to type out text through this method with today’s technology.

Hawking needed one muscle if he wanted to register his actions, but with P300 he wouldn’t even need that.

In this video, the subject is asked to focus on the letter he wants to type. Whenever the letter he focused on is flashed on the screen, he reacts to it, thus the P300 can be observed. Then, it becomes possible for the software to analyze which letter the subject meant to type based on his observed cognitive output.

Devices that use similar approaches to allow people to type hands-free are named “P300 Spellers”. These devices can come to the rescue of people who have trouble speaking and writing because of their medical conditions.

Hawking was so used to his own device that he refused to use this new technology. Unlucky for him, this technology was at its infancy when he was young.

“I keep looking into new assistive technologies, and I have experimented with eye tracking and brain controlled interfaces to communicate with my computer. However although they work well for other people, I still find my cheek operated switch easier and less fatiguing to use.” -Stephen Hawking

It can be easily said that this type of technology will become a huge part of people’s lives suffering from similar conditions in the future. Not only for typing or surfing the web; but for using other applications and programs


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