This is where brain deterioration is caused by damage to the fragile blood vessels that supply the brain with the oxygen and nutrients it needs to continue functioning. The damage can be caused by small blood clots, which can induce mini-strokes, or the gradual thickening of the blood vessel walls in the brain, which reduces blood flow and leads to cell death.
Symptoms of vascular dementia can include problems with memory, language, decision-making and co-ordination.
Scheltens says that people with elevated cholesterol, high blood pressure or cardiovascular diseases, such as Type 2 diabetes, are more vulnerable to vascular dementia. “Eighty per cent of the time, blood pressure is the cause of these vascular changes,” he says. “So that and cholesterol changes are really the contributing factors to the vascular changes in the brain that occur relatively late in life.”
The main treatments are a combination of lifestyle recommendations such as increasing exercise, quitting alcohol and smoking, and losing weight, along with medicines to manage blood pressure and cholesterol.
However, cases where dementia is driven entirely by vascular problems are relatively rare. “Most often in elderly patients over the age of 75 or 80, it’s a combination of Alzheimer’s disease and vascular changes on top of it,” he says.
While mixed dementia has traditionally been regarded as one of the least common forms of the disease, Scheltens says that neurologists are increasingly realising that the vast majority of dementia cases actually feature a mixture of elements from various individual dementias.
“If you ask pathologists, they’ll say that in the elderly, it’s almost all mixed,” he says. “The pure cases of Alzheimer’s are quite rare, and they tend to be people who have early-onset Alzheimer’s. All the rest usually have combinations of Alzheimer’s and vascular changes, or other pathologies such as Lewy bodies.”
He believes that progress in brain imaging will increasingly allow doctors to make more accurate assessments of what exactly is taking place in the brain in each dementia case. In the coming years, this could make it easier to design combinations of therapies and lifestyle interventions that are suitable for each particular patient.
“It’s still early days with some of these disease-modifying treatments which are being developed for Alzheimer’s and other dementias,” he says.
“But in future, the first step will be to inform the patient of lifestyle changes to treat any cardiovascular risk factors, and then try to apply combinations of available treatments.”