Two letters written by Admiral Lord Nelson have been sold at auction for a total of £65,500. One was written with his right hand, the other - following the amputation of his right arm in 1797- with his left. But how hard is it to learn to write with the other hand?

Lord Nelson may be one of history's greatest British naval heroes.

But in some ways, the plight of the naval commander - who lost his right arm at the Battle of Santa Cruz de Tenerife - is a modern story.

It is hard to know exactly how many British Armed forces personnel have had to learn to write with their other hand as the result of an injury.

Last year the British Limbless Ex-Servicemen's Association said there had been 10 single arm amputations and 16 triple limb amputations since 2001. Many other service personnel will have been left with injuries that didn't result in the loss of a limb, but left them unable to write.

Image caption Letters from Nelson in 1804 (left) and 1793 (right), written with different hands

Of course it's not just the military that's affected. Many people lose an arm, or the use of an arm, as the result of an accident.

Mike Swainger, 34, from Hull, lost his right arm and right leg after he was hit by a train when playing near the track at the age of 13.

Horatio Nelson 1758-1805 One of Britain's most famous war heroes, led Royal Navy to several victories against Napoleon

Lost his right arm at Battle of Santa Cruz de Tenerife in 1797

Died during his his most famous victory at Trafalgar; celebrated by Nelson's column (pictured) BBC History - Admiral Horatio Lord Nelson

He spent three months recovering in hospital but started doing school lessons on the ward after two weeks.

"I couldn't get out of the school work so I had to start using my left hand all the time. It was like going back to my younger days and learning to write and to draw pictures. I knew I could write but I wasn't making the same images. It was like nursery writing.

"I persevered with it though and all in all it took about a month before my writing became neat and joined up," he says.

Roy Haycock, 79, from Bury, Lancashire, was only five years old when he lost his right arm after he was hit by a lorry walking home from school. He thinks his age had a huge impact on his recovery.

"Before the accident I could do the basics like writing my name, and a couple of weeks after it I was back doing lessons and I was printing letters with my left hand.

"I'd go to pick up my pen with my right hand a lot, partly from habit and partly because I used to think I could still feel my fingers. But I was so young 'can't' wasn't a word in my dictionary," he says.

Image caption Many stroke survivors find writing difficult

Strokes - which affect about 152,000 people in the UK every year - can also result in people being unable to use their normal writing hand.

About 40% of stroke survivors are left with a non-functioning arm and between 40-70% find it difficult to write, according to the Stroke Association.

For Maureen Lawson, of Heron Cross, Stoke-on-Trent, who was paralysed down her left-hand-side after three strokes last year, it meant changing the habit of a lifetime.

"I wasn't sure if I'd regain any movement on the left side and as a left-hander one of the first things I thought about is what will I do if I have to sign important documents," she says.

The 57-year-old learnt to write with her right hand by tracing letters and shapes in a children's book. Although she has some movement back in her left arm, she says there isn't much feeling so it's hard to hold a pen.

"I've ended up ambidextrous. But I have to focus on everything I do with my left hand, so if I'm in a rush I'll use my right one because I can do it now without thinking," she says.

Image caption Examples of Maureen Lawson's handwriting

Whether a person actually loses a limb or the ability to use it due to something like a stroke, the underlying science behind training a non-dominant side to take on major tasks is similar, according to Paul Williams, the senior training lead at the Stroke Association.

"Every movement requires messages to travel along connections and pathways in the brain. Within each and every connection in the brain there are tiny gaps. For a movement to be made, a message needs to jump across this gap. The more often the signals jump across the gap the easier it becomes to do it and the more natural the final movement.

"The complication with strokes is if the parts of the brain that control the nerve cells are damaged then they can't automatically send the messages to tell the body to move," he says.

Of course nowadays most people write less and type - and text - more.

And with the advent of voice-activated software learning to write is not always a top priority for patients.

However Melissa Jacobs, 37, an occupational therapist at Queen Mary's Hospital in Roehampton, London, says it's important to encourage people to learn some writing, even if it's just their signature or to fill in a form.

Image caption Mike Swainger (front, centre) with the Hull FC wheelchair rugby team

If people persevere, the rewards are long lasting. Swainger, who used a prosthetic right arm for 20 years, still writes and texts with his left hand.

However 18 months ago he also became the first person in the UK to be fitted with a bionic arm on the NHS. It has enabled him to train as a rugby coach and set up the Hull FC Wheelchair Rugby team.

"It's interesting because before my accident I wanted to be a professional rugby player and my life has sort of gone full circle now. I've been able to do all the things I wanted to do," he says.

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