Cognitive damage from undetected strokes is too often dismissed simply as part of old age, but deterioration can be avoided if caught early, says an Ontario neurologist.

University of Western Ontario neurologist Dr. Vladimir Hachinski is chair of the International Society for Vascular Behavioral and Cognitive Disorders, representing doctors from 41 countries.

The group recently called for more funding for the prevention and treatment of strokes and Alzheimer's disease, arguing silent strokes often lead to declining mental abilities.

They say there is almost no research in this area despite the high costs of hospitalization, nursing homes and the loss of life.

Hachinski says for every stroke we know about, there are five we don't know about. These are silent strokes with no immediate symptoms such as dizziness.
 
To show the difference between a fading memory that comes with age, and brain damage that could be caused by a silent stroke, Hachinski uses the illustration of losing your car keys.

"When you find the keys, you say, 'Ah hah, stupid me. I left them there.' If you find the keys and you have no clue you put them there, then that's not aging," he told CBC News.

Hachinski says another indicator of brain damage from silent strokes is an inability to make decisions.

"One of the things that gets better with age is actually judgment, because people can chunk their information, they can put it in context," he says.

He says anyone over 60 with a family history of stroke or Alzheimer's disease should make an appointment for a medical assessment because brain scans can usually turn up evidence of silent stroke.

By preventing the silent strokes, it may be possible to if not prevent, then at least delay Alzheimer's disease, Hachinski told the London Free Press.

"At the time you can diagnose Alzheimer's disease, you can do very little because it is a relentless, fatal disease. If we are going to make a difference, we are going to have to start much earlier," he told the paper.