An exceptional man

Stephen Hawking has survived almost 40 years with a disease that usually kills people 14 months after diagnosis. Roger Dobson asks why

Stephen Hawking developed motor neurone disease when he was in his early 20s. Most patients with the condition die within five years, and according to the Motor Neurone Disease Association, average life expectancy after diagnosis is 14 months.

But Professor Hawking, the Cambridge University physicist and cosmologist and author of A Brief History of Time, has confounded the statistics and recently celebrated his 60th birthday. No one is thought to have survived for so long with the incurable condition, which kills three people a day in the United Kingdom.

“Stephen Hawking is a fascinating case, and neurologists always puzzle over it. The case is fascinating because of the early onset and the length of time the disease has run,” one neurologist said.

Motor neurone disease (MND), or amyotrophic lateral sclerosis, is a progressive, usually fatal neuromuscular disease. It attacks motor neurones in the spinal cord and lower brain, which transmit signals from the brain to the voluntary muscles throughout the body.

“The average duration of survival from diagnosis is about 14 months, but it varies enormously,” says Professor Nigel Leigh, professor of clinical neurology at King's College, London, and director of the King's MND Care and Research Centre.

“We have found that the survival in younger patients is strikingly better and is measured in many years—in some cases more than 10. Among people in their 50s and …