When a medical specialist asked me to draw a clock on a jotter pad, I dryly asked: would he prefer the numerals to be in Roman or Arabic?
Drawing a clock is apparently a simple test to check if dementia is hovering around the corner.
Of course, dementia is a syndrome and Alzheimer's disease is the primary cause of its symptoms.
Noting my age, as part of a general health check my specialist had asked whether I had noticed any serious lapses of memory.
I told him that, yes, I had noticed when I'm at a social event talking to young ladies, I have a tendency to forget I'm married.
The quip appeared lost on him, as he stonily asked me to draw the clock.
To my relief, he reached the conclusion that I was in good mental and physical health for my age, in spite of a lifetime of eating too many meat pies and drinking my fair share of alcohol, as befits a journalist of the old school.
I have had mates in the media business who succumbed to Alzheimer's in their late 40s, so I have always been grateful that lady luck has been on my side in the longevity stakes.
A recent research paper from the Mayo Clinic in the US suggests I might have been helped along the way by my chosen career as an editorial cartoonist.
According to the Mayo study, following a creative pursuit such as painting or drawing -- even in old age -- lowers the risk of developing the first signs of dementia by 73 per cent.
Researchers followed 256 people who were over 85 years old for four years. The volunteers reported their participation in arts, such as painting, drawing and sculpting, and other crafts, such as woodworking, pottery and sewing.
After four years more than a third had developed mild cognitive impairment, which often leads to dementia.
But those who had taken part in arts were 73 per cent less likely to have suffered memory or thinking problems.
Having placed my brain on an exercise cycle every day for the past 50 years, drawing editorial cartoons, the benefits appear not in monetary gain, but in apparently keeping my memory cells glued together.
When I mentioned this phenomenon to my editor, he immediately responded by suggesting I should be paying my employers for the health benefit I'm enjoying in exchange for being put to work.