Geoff Old played three tests and 14 matches for the All Blacks between 1980-83 and is best remembered as being part of a powerhouse Manawatu pack that held the Ranfurly Shield.

WATCH: One of the greatest All Blacks reveals how the big hits during his playing days may have taken a terrible toll.

An iconic All Black has revealed he has dementia. Waka Nathan, a flanker for the ABs in their golden era in the 1960s, has stage two Alzheimer's disease.

Waka Nathan doesn’t just answer the door, he fills it. This, you can’t help but think, is how you want all your sporting heroes to look like when they’re 75 — upright and tall, Nathan has an undeniable presence and looks in great health On the outside, at least.

Wayne Smith, the All Black assistant coach whose brain is one of the most sought after in rugby, has admitted to concern over his long-term health.

Scan of Wallabies prop's head shows the shocking effects a decade of rugby has taken on his face and nose.

A link seems likely between serious head-knocks and dementia and the strain rugby-related injuries could put on the health system will be monitored, Health Minister Jonathan Coleman said.

Brent Rowlands was a little confused and more than a little peeved at first time. The second and third times, he recognised there may be something wrong.

New Zealand Rugby - while sympathetic and moved by the plight of former players battling dementia - says its obligation is to protect the current generation.

Source: BBC

A sharp rise in ACC claims involving rugby concussions has the organisation bracing for its first dementia case.

Rugby Players' Association Head Rob Nichol discusses the issue of concussions in rugby.

Rugby Players' Association Head Rob Nichol discusses the issue of concussions in rugby.

The boss of Taranaki rugby says the plight of the '64 team will strike a chord with many in the province.

They were bound by university flatting, rugby and a lifelong friendship. They were separated only by a shared illness and tragedy.

While top neurologists are increasingly seeing persuasive signs of a link between rugby and dementia, one former Lion has no doubt the connection is real.

A number of Taranaki's old rugby legends and their families are suffering. As Dylan Cleaver reports, they have an eerily similar story to tell.

In a special investigation the Herald explores the connection between concussions suffered on the rugby field and dementia.

A Herald investigation has found a cluster of dementia cases from the Ranfurly Shield-winning team of 1964, and loved ones are asking questions.