The news was confirmed by Dawn Astle, daughter of former West Bromwich Albion striker Jeff Astle and co-founder of the Jeff Astle Foundation.
A post on social media with the hashtag #dementiainfootball read: “I am very saddened to say that former Hibs, Arsenal, and Aston Villa player Alex Cropley has been diagnosed with dementia. My thoughts are with Alex, Liz and all the family.”
Astle died in January 2002 from chronic traumatic encephalopathy (CTE); a progressive, degenerative brain disease often found in athletes with a history of head injuries.
Astle's case is believed to have been caused by repeated, low-level brain trauma associated with repeated heading of footballs and the foundation’s main aim is to raise awareness of brain injury in sport at all levels.
Born in the garrison town of Aldershot, Cropley, affectionately known as Sodjer – the result of a myth that his father was in the forces – began his career with Edina Hibs, becoming the first product of the side to make the step up to senior football when Bob Shankly signed him for Hibs in 1968.
However, it was under Eddie Turnbull that Cropley made a name for himself as a diminutive figure with a ferocious tackle.
A classy inside-left, he made 199 appearances for Hibs scoring 49 goals and helped them to League Cup success in 1972 as well as two Drybrough Cup victories. He suffered his first serious injury against Falkirk at Brockville; a broken ankle caused by a challenge from future Aberdeen and Manchester United boss Alex Ferguson.
Speaking in 2015 Cropley said: “Ned reckoned it was an outrageous tackle and wouldn’t speak to Fergie for a long time afterwards. But the referee didn’t think it was that bad – he was telling me to get up.
"I had to be stretchered off. The Hibs director Sir John Bruce, a top surgeon, thought I’d only hurt the ligaments and strapped my ankle.
"The next morning Dad had to give me a fireman’s lift down the stairs to take me to hospital. The ankle was broken and when I was told I needed a screw put in I thought my career was over.”
Cropley left in December 1974 to sign for Arsenal in a deal worth £150,000 after turning down Chelsea, but suffered a broken leg early in his Gunners career and broke it again soon after his return.
Unable to hold down a regular starting place he moved to Aston Villa in September 1976 and was part of the team that won the League Cup in 1977.
Cropley suffered another leg break just months after the League Cup success and after 18 further outings joined Newcastle on loan during the 1979/80 season, playing three times for the Magpies in Division 2.
He didn't feature for Villa on his return and after a stint with Toronto Blizzard in the North American Soccer League signed for Portsmouth in September 1981. But injuries caught up with him and at the relatively young age of 31 Cropley was forced to hang up his boots.
He was capped twice by Scotland, playing in victories against Portugal and Belgium in 1971, and after retiring from the game worked as a taxi driver.