I am 47 years old at the time of writing this, I first discovered I had grapheme-color synesthesia (colored letters and numbers) when I was in primary school, and since then I have definitely noticed a steady fading of my condition over time.
The sensation is still strong, just faded a little.
Not all my colored letters have faded.
Synesthesia and Pool (8-Ball)
One of my favorite games to play is pool (8 ball) and most ball colors don't line up with my synesthesia. Only two balls match perfectly:
One thing I've noticed after playing pool for 30+ years, is my 2-blue and 3-red association is still as strong as ever. Only the other numbers have faded.
So what does this mean?
According to Vilayanur Ramachandran, an American neuroscientist who studies this subject, synesthesia is caused by a cross-wiring of the brain which associates different senses together. In normal people this cross-wiring is pruned away over time but in synesthetes this pruning is not as effective.
My brain must be slowly pruning away the non-reinforced associations.
So does synesthesia fade over time? Here's what my experience tells me:
Synesthesia can fade with age as non-reinforced neural connections in the brain are pruned away over time. Associations that make sense will show resistance to this pruning and are likely to last longer. How quickly pruning occurs will be different for each person and is likely governed by genetics.
My synesthesia is still quite strong so I can't see it disapearing any time soon.
For me, synesthesia is for life.