A fair amount of research on raised blood pressure, hypertension, and its risks has been published of late. Hypertension is a downstream consequence of loss of elasticity in blood vessels. That loss of elasticity arises from the molecular damage at the root of aging, and the resulting hypertension is one of the more noteworthy mediating mechanisms by which that low-level biochemical damage is translated into structural damage to organs. Hypertension causes pressure damage to sensitive tissues, increasing the rate at which small blood vessels rupture, killing the nearby cells. This is particularly important in the brain, where regenerative capacity is limited. Individually, each tiny area of damage has little effect, but taken as a whole it adds up over time to contribute to cognitive decline.
A new study indicates that patients with high blood pressure are at a higher risk of developing dementia. This research also shows (for the first time) that an MRI can be used to detect very early signatures of neurological damage in people with high blood pressure, before any symptoms of dementia occur. High blood pressure is a chronic condition that causes progressive organ damage. It is well known that the vast majority of cases of Alzheimer's disease and related dementia are not due to genetic predisposition but rather to chronic exposure to vascular risk factors. The clinical approach to treatment of dementia patients usually starts only after symptoms are clearly evident. However, it has becoming increasingly clear that when signs of brain damage are manifest, it may be too late to reverse the neurodegenerative process. Physicians still lack procedures for assessing progression markers that could reveal pre-symptomatic alterations and identify patients at risk of developing dementia.
This work was conducted on patients with no sign of structural damage and no diagnosis of dementia. All patients underwent clinical examination to determine their hypertensive status and the related target organ damage. Additionally, patients were subjected to an MRI scan to identify microstructural damage. To gain insights in the neurocognitive profile of patients a specific group of tests was administered. As primary outcome of the study the researchers aimed at finding any specific signature of brain changes in white matter microstructure of hypertensive patients, associated with an impairment of the related cognitive functions.
The result indicated that hypertensive patients showed significant alterations in three specific white matter fiber-tracts. Hypertensive patients also scored significantly worse in the cognitive domains ascribable to brain regions connected through those fiber-tracts, showing decreased performances in executive functions, processing speed, memory and related learning tasks. Overall, white matter fiber-tracking on MRIs showed an early signature of damage in hypertensive patients when otherwise undetectable by conventional neuroimaging. As these changes can be detected before patients show symptoms, these patients could be targeted with medication earlier to prevent further deterioration in brain function. These findings are also widely applicable to other forms of neurovascular disease, where early intervention could be of marked therapeutic benefit.