Producer, Brain Hospital
Until three years ago teacher Barbara Cullen was fit and healthy, spending most of her leisure time outdoors pursuing various hobbies which included a passion for surfing.
Barbara had to rely on oxygen to ease the pain
Suddenly out of the blue she started getting severe headaches.
As they first began around Christmas time she wondered if it was due to yuletide excess, but the headaches became more and more severe. All her husband Fred could do was to sit and watch.
"To actually watch somebody holding their head in their hands and then getting down on their knees on the floor and literally shaking, you think this is not a normal headache," he said.
"I initially assumed this is something that she's going to die from, she's going to have a brain haemhorrage."
Barbara was getting the headaches up to eight times every day - the pain was so intense that she began to contemplate taking her own life.
"It's excruciating and it's there all the time, it doesn't go away. And being in constant pain you are dragged down, it's a vicious circle, because I can't sleep, I'm constantly tired.
"You have to take morphine-based painkillers and you become disorientated and it would be quite easy to just take a few extra and just get rid of the pain once and for all."
The only thing Barbara could do to help ease the pain was to breathe in pure oxygen, she needed to keep a supply close at hand at all times even when at work.
Eventually, Barbara was referred to the National Hospital for Neurology and Neurosurgery in London.
The surgery does not work for all patients
The National is one of Britain's leading brain hospitals where around 100 consultants treat everything from head injuries to Parkinson's disease, paralysis to epilepsy.
Some doctors here are the only specialist of their kind in the country and for many patients the National is their last chance.
At the National Barbara's headaches were diagnosed as cluster headaches.
The pain they cause is thought to be ten times worse than childbirth - they have been nicknamed suicide headaches because of the excruciating pain - like being stabbed in the head with a needle.
Barbara's only chance of getting rid of the pain was to have an operation to implant an occipital nerve stimulator into the back of her head.
Barbara's surgeon was Mr Laurence Watkins - the only surgeon in the country who carries out this operation.
No-one knows exactly what causes a cluster headache but it is thought to be abnormal activity deep inside the brain.
Doctors also are not sure how the occipital nerve stimulators stop the headaches but they think that the stimulator modifies the abnormal activity.
Mr Watkins was attracted to brain surgery as a student because there was still so much to learn about the brain.
"The nervous system is one of the last great frontiers we don't understand and yet we all have a brain, it is what makes us what we are.
"We still know relatively little about it and I think it is the biggest challenge still around."
Barbara's husband Fred was relieved when he found out she would be suitable for the pioneering surgery.
"If we hadn't heard of this operation I don't think she'd be here today," he said, speaking before the operation.
"This is the treatment and if this doesn't work the future doesn't bear thinking about, it really doesn't. This operation has got to work."
In consultation with Barbara, Mr Watkins had to explain that the operation was relatively new and that he could not predict the outcome.
"My impression is that it seems to work in about two out of three people. Of course there is always a slight unknown with something that hasn't been around for a long time.
"We're only really doing it with patients who have chronic headache continuously and where nothing else has worked."
Barbara's operation involved planting two electrodes near the occipital nerves which run up the back of her head, through an incision in the skin in her neck.
The electrodes were then connected to a stimulator - a little like a pacemaker - which was implanted in her abdomen.
Barbara was awake for the first part of the operation to position the electrodes as she had to tell Mr Watkins how far up the back of her head she could feel the "tingling sensation" which was generated by the stimulator.
She was then anaesthetised for the rest of the procedure to implant the stimulator in her abdomen.
The hope was that when the stimulator is turned on after the operation her headaches will disappear.
Barbara's operation was a success and two months after leaving hospital she was back surfing.
"The fact that I can even think about going in the sea swimming or anything else is just unbelievable. It's given me a new lease of life, there's a future now so I just want to go out and enjoy it."
Brain Hospital is on Wednesdays at 2100GMT on BBC One from 22 November 2006