Some types of dementia are actually a result of many tiny, unnoticed strokes damaging the brain over time, researchers at the Krembil Neuroscience Centre in Toronto, Canada, have found.
This suggests that this type of dementia could be treatable — probably through lifestyle changes.
The findings come from a study of five individuals who had their brains scanned over 16 consecutive weeks (Conklin et al., 2014).
The relatively frequent brain scans revealed that tiny spots were appearing on the MRI, which are characteristic of small strokes.
The appearance of the spots had not been noticed before because previous studies have scanned the brain at longer intervals — typically every year.
The spots did not produce any symptoms but, over time, it is thought the lesions can form into areas of white matter disease that are characteristic of dementia.
Around 50% of older individuals have this kind of white matter disease in their brains, although for many it is harmless.
For some patients, however, the disease can progress until the symptoms become severe.
Dr. Daniel Mandell, who led the study, said:
“We were surprised.
The findings suggest that the tiny, silent strokes are likely much more common than physicians previously appreciated, and these strokes are likely a cause of the age-related white matter disease that can lead to dementia.”
While there are no treatments for degenerative dementias, as this is vascular it may be possible to stop, or at least slow down, the process.
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Dr. Frank Silver, Director of the Krembil Neuroscience Centre and one of the study’s authors, said:
“We don’t yet know whether these small strokes are responsible only some or most of the white matter disease seen in older patients.
But in those where it is the cause, the detection of white matter disease on brain imaging should trigger physicians to treat patients aggressively when managing stroke risk factors such as high blood pressure, diabetes, high cholesterol, cigarette smoking and lack of exercise not only to prevent further strokes, but also to reduce the development of cognitive impairment over time.”