I have lived my whole life as a healthy person. I had my tonsils and adenoids out when I was five, and I had an operation to repair an inguinal hernia. That's it. Especially because of my work in disability, I know this could change tomorrow. It may already have begun to change – there may already be something lurking inside me that will later manifest as illness or debility.

Over 30 years ago, in my work as a psychologist, I was fortunate to be consulted by an exceptionally articulate and intelligent middle-aged man. Amongst other concerns he had, he worried that he had early onset dementia. Something, he felt, was not quite right. To me, there was absolutely nothing to support his fear. I had seldom met someone so articulate, and whose thinking seemed to be so well organised and controlled. But in order to respect his experience, and to get a more expert view, I decided to refer him for a second opinion. Neuropsychology was not very developed as a field in Cape Town in those days, and I referred my patient for an assessment to a neurologist, writing in my referral letter that I could find no evidence of dementia, but wanted to be absolutely sure. Not unexpectedly, I got a rather exasperated response from the neurologist, who also found not a shred of evidence of dementia, and seemed irritated that I had wasted his time. I worked with the patient for a number of years, and never once in those years did I revise my view that he did not have dementia, but we did discuss in some detail his fear of dementia and of what it might have been about in terms of how he felt about himself and his future.

Many years later, and long after we had stopped seeing each other, I read a newspaper article about a freak accident that had befallen this patient's brother, to whom he was very close.