How Stephen Hawking Worked

After Hawking was diagnosed with amyotrophic lateral sclerosis (ALS) at 21 years of age, he was forced to balance the stresses of academic life with physical illness. The disease negatively affects brain and spinal neurons, making patients lose control of voluntary motor function and movement.

During the first few years, his condition worsened rapidly. Soon he relied on a wheelchair. By 1974, Hawking was unable to feed himself. Fortunately, the progression of the disease slowed a bit, eventually becoming more gradual over the years. With time, however, he still began losing the use of his voluntary muscles, hands and certain facial expressions.

Hawking previously used his finger to control a computer and voice synthesizer. But once he lost use of his hands, he started depending on twitching a cheek muscle to communicate. Most computers designed for him relied on running lists of words. Whenever the cursor reached a word or phrase he wished to use, Hawking twitched his cheek muscle to select it. Then he'd go on to the next word until he created a sentence. In the 1990s, by selecting words with his finger, he could pick 10 to 15 words per minute. But with the difficulty of twitching a cheek muscle, he could select just about one word per minute [source: Ferguson]. Because of this, most of Stephen Hawking's speeches and interviews were done in advance to save time.

Hawking died at age 76 at his home in Cambridge, leaving behind three children and three grandchildren. "He once said, 'It would not be much of a universe if it wasn't home to the people you love.' We will miss him forever," said his children in a joint statement released after his death in 2018. A 2014 movie about his life, "The Theory of Everything" won an Oscar for Eddie Redmayne who portrayed him.

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