Mr Winn, 63, first began realising something was wrong when he began experiencing feelings of numbness and loss of control of his limbs on the left-hand side of his body.
Other symptoms included short-term memory loss and vision issues.
Eleven years on from the diagnosis, the couple has had to make some adaptations to their walks.
Speaking to The Telegraph Ms Winn, 61, said: “I think the main thing is we are not camping, we have booked places for us to stay at as we complete the walk.”
“In Moth’s case, exercise does seem to alleviate his symptoms, but we just have to pace ourselves more than we used to and listen to Moth’s body, as it tells us what we can do.”
The Winns hope to arrive in Westminster on April 18, where they will recover for two days before walking the London Marathon.
Ms Winn added: “We really want to raise awareness of the conditions as many medical professionals have never come across either of them before.
“As this year PSPA celebrates its 30th anniversary this year, we wanted to do something to mark it.”
