At 77 she met us at the airport in a Ford Taurus, spent three days driving us around the city before taking us on a car ferry to visit an island – sprightly, fit, an active and inquisitive mind and an encyclopaedic memory, she was the model of what life as a senior should be like.

At 87, she had decided the long car journeys should be a thing of the past but had no problem in the city.  She made up spare beds for our visit; made breakfast in the mornings and joined us in restaurants for meals in the evening.  Her interest in politics and current affairs was as keen as ever; her recall of every detail of the family tree was impeccable.

A few years later and there is evident pain in her face as she admits she does not recall events; she is annoyed at being told of something a month earlier; she rationalizes a failure to recall an important moment. There was no purpose to be served in talking of forgotten things, much happier for all to stay in the realm of the remembered.

Returning, I searched out words from Sebastian Faulks’ Human Traces, words to which I seem to have frequent recourse.

He looked up and forced himself to regroup. ‘Yes. Yes. I just have to say, while I am still able, a sort of goodbye, or at least an au revoir. Some weeks ago I … Er, I suffered a peculiar experience. I do not wish to go into it except to say that I appeared to lose my memory. I was in a police station with no recollection of how I had got there. I was not unhappy, I just did not know what was going on. I was like King Lear. “Methinks I should know you, and know this man;/ Yet I am doubtful; for I am mainly ignorant/What place this is; and all the skill I have/Remembers not these garments; nor I know not/Where I did lodge last night.” Anyway, to … To cut a long story short, I have been to see various distinguished gentlemen¬at the hospital in Queen Square and it appears that I am in her early stages of some kind of senile or pre-senile dementia.

‘Rather interestingly, it has been named after Alois Alzheimer . . .

. . . He looked back to his postcard. It said: ‘Age.’

‘Yes. Age. I am rather young to have this sort of thing, though perhaps sixty does not seem so young to the children at the far end of the table. The truth is that we know very little about this illness. We know very little about anything, as a matter of fact. Never mind. It is really not important. It is just that one day I may no longer know your name, and I ask you to forgive me if I pass you in the street or on the stairs and my face does not light up with love or recognition. Please forgive me. I shall no longer be myself. I am going into a dark country and I very much wanted to say goodbye to those that I have loved before I go. . .

. . . He gazed once more down through the mist of faces until he saw the features of the woman he had loved – no longer young, but red and twisted with grief, shining with tears.

‘I have been blessed beyond what any man could hope or wish for,’ said Thomas. ‘All I ask now is somewhere safe to live. I must pull in sail and lower my sights from the horizon. I am quite content to do so because I have been so fortunate in my life.  I always felt that if I had to make a speech like this I should find some Shakespearean eloquence. But it is too late and the plain words will have to do. As a doctor, I have achieved absolutely nothing. Nothing at all, though God knows I tried. But in love I have been rich. Once long ago I finished a lecture in another place by saying we should try to make our lives a hymn of thanks – or some such phrase. I do not think it was a very memorable phrase, even to someone without my difficulties. I shall do my best to follow my own advice. All I ask is for your forgiveness.’

He looked one last time down the table of anxious faces. ‘My mind may not know you,’ he said, ‘but in my heart you are remembered.’

Faulks’ words seem the most profound understanding of what must be the worst of illnesses.