After being seen by a number of doctors and specialists came the diagnosis - Progressive Supranuclear Palsy, known to some doctors as the Mona Lisa Disease because of one of its classic symptoms of unmoving, staring eyes.
'When the doctor told me, he was not at all clear about what the condition was and, I felt, slightly discouraged questions. He looked young, but overworked and under pressure. So was I,' said her husband, Brigadier Michael Koe.
'Should I tell Sara? What should I tell her? I needed time to think. Was there a cure? How would we cope? She was only just 54. Over the previous year she had been desperate for someone to tell her what was wrong with her eyes . . . but what an answer.'
Dr Andrew Lees, consultant neurologist at the National Hospital for Neurology and Neurosurgery in London, and a leading expert on PSP, says the condition 'presents one of the most arresting and distressing images in neurology. Like that of the Mona Lisa, the hypnotic immutable stare fixes your attention and draws you to the bedside from the other end of the ward or the other side of the street.'
PSP is a rare illness for which there is no known cause, no cure, and no treatment. From diagnosis to death can take just seven years - varying between individuals - and in the final stages its victims have no balance, cannot swallow, talk, or move their eyes, but remain mentally alert.
PSP, which is estimated to affect 6,000 patients in the UK at any one time, is one of the last really harmful diseases about which almost nothing is known. Little research is being done and many doctors are still failing to spot the symptoms of one of the grimmest of all neurological conditions. It is estimated that only one in five cases is properly diagnosed, the remainder wrongly treated as cases of dementia or Parkinson's disease.
Neurologists do know PSP is not inherited, but a random illness where the neurons in the mid- brain deteriorate, affecting vision, balance, swallowing and speech. Theories about its cause range from toxins in the environment to a blow on the head. The almost total lack of knowledge about the disease, even among doctors, added to the trauma of diagnosis for Mrs Koe and her husband, a former officer in the Royal Green Jackets.
At their Northamptonshire home, Gayton Manor, now for sale because of its unsuitability for his wife, he said: 'We were shocked, frightened and upset. Sara was an energetic, mentally razor-sharp, superactive woman, full of the joys of life, and yet had to be told that she had a formidable disease that could have her in a wheelchair within two years.'
As his wife's condition slowly deteriorated - she now has difficulty with swallowing and with speech, and occasionally loses her balance - he set about finding out more about a disease which, unlike another rare neurological condition, the higher profile motor neuron disease, is almost unknown outside the small group of victims, their and relatives and a few specialists. 'Ask your average doctor about PSP and he won't have a clue,' said Brigadier Koe.
After his wife's diagnosis was finally confirmed at the National Hospital, he talked to specialists, visited other victims and their families, and tracked down more sufferers in the United States. He attended a US medial conference on PSP, and met Congressmen and then MPs. He has now persuaded professors from the US, Spain, Germany and France, to be part of a medical advisory group for a new pressure group and European charity he and his wife are setting up to fund research into the disease.
'At the time we were appalled to find out that so little research was being carried out and we set out to do something about it. It has been known as a separate disease for 30 years but virtually nothing is known about it,' he said.
Dr Lees, who will chair the group, said: 'It is a remarkable illness which has very specific features. Apart from the eyes, the gait of these patients has been described as similar to that of a dancing bear. In the final stages the eyes do not move in any direction, up or down, or side to side, but remain staring. When they want to look at something the whole head has to turn.
'The prognosis for PSP patients is much grimmer than Parkinson's. We don't have a cause or a cure, and we don't really have any effective palliative. The symptoms are gradual and the illness from beginning to end in the average person is seven years. We know that at post mortem the brain resembles that of a boxer.
'In classic cases there is a disintegration of personality with a difficulty in switching from one idea to another. There are early problems with balance with a tendency to fall over backwards and then eye movement problems. Eventually the patient cannot move the eyes or speak.
'It is one of the very grim, crippling diseases. It affects a small number of people, but we believe there is considerable under-reporting. Some areas of medicine have an abundance of funds, but PSP does not. We are hoping the new group will get things moving so we can carry out more research.'
That view is echoed by Professor Lawrence Golbe, Professor of Neurology at the Robert Wood Johnson Medical School in Baltimore. He said: 'If, as I suspect, PSP proves to be much more common than has been assumed, improved diagnosis will draw the attention of more researchers to finding the cause and cure.'
Meanwhile, the first goal for Brigadier Koe and Sara and their new charity, chaired by their local MP, Michael Morris, is to raise enough money to fund the first PSP full-time researcher at the National Hospital for Neurology.
One of the problems of a disease like PSP is that its very rarity makes it an unattractive commercial investment for research because of the small number of potential patients and profits from any resulting drug. At least acceptance of the fact that PSP affects more people than was thought may have some influence on the pharmaceutical companies.
But it will be uphill work. 'We want to do so much. We want to attract the pharmaceutical companies to carry out research. We want to fund research, to organise meetings and workshops of leading neurologists across Europe, identify areas for research and bring this disease out of the shadows and into the spotlight so people know what it is and want to do something about it,' said Michael Koe.
'Among sufferers and carers there is a strong feeling of shameful neglect of this obscure disease by the medical profession.'
PSP patients themselves often find it difficult to talk about what the disease means to them. Michael Koe carries with him a description given by one sufferer of the anguish of being mentally alert in a body that is slowly grinding to an inevitable halt: 'I have two strong legs that I can move, but when I walk I fall. I have a strong voice, but when I talk no one understands. I have good vision, but I cannot see, I cannot read. My throat is healthy, but I cannot eat without choking.'
For information on the PSP Association, write to Brigadier Michael Koe, Gayton Manor, Gayton, Northampton NN7 3HE or ring Anne Mathon 071- 383 3513 or 0923 230959.