Blood pooling in the brain like stagnant water after a rainfall is problematic, to say the least. 

Scientists at Japan’s RIKEN Center for Biosystems Dynamics Research (BDR) now say that monitoring for this effect can allow for early treatment of conditions such as Alzheimer’s and idiopathic normal pressure hydrocephalus (iNPH), another type of dementia.

Although to some degree, ventricular enlargement is a normal sign of aging, left unchecked, it can develop into ventriculomegaly, which is an early sign of dementias such as Alzheimer’s and iNPH.

These two conditions are both prevalent among the elderly and can benefit from early treatment. 

With each beat of our heart, blood in the lungs picks up oxygen that it will deliver throughout our entire body. Deoxygenated blood then drains back through our veins for another cycle. In the brain, this drainage occurs by two different pathways, depending on whether blood drains from near the surface of the brain or from deeper within. 

Using magnetic resonance imaging (MRI), a powerful medical imaging technique, the BDR team observed that these two drainage pathways fall out of sync as we age. 

In their study, the BDR group found that in healthy aging brains, the time lag between the two types of drainage keeps pace with the naturally enlarging ventricles. Measuring this lag, therefore, appears to be a good way to keep track of the aging brain’s health. An abnormally large difference between the drainage lag and ventricular size might predict ventriculomegaly, which would signal the need for further tests and medical interventions. 

Many types of dementia benefit from prompt medical action. Acting early in the onset of iNPH, in particular, can have a dramatic effect. Unlike dementia caused by Alzheimer’s, for which there is currently no cure, removing the fluid that builds up in the ventricles can actually reverse that of iNPH. 

iNPH is a rare condition, estimated to affect between 1.5% and 3.7% of the population aged 65 and older. As of 2018, an estimated 52 million Americans were 65 or older. The percentage range of those possibly afflicted with iNPH would then translate to between 780,000 and 1.9 million American seniors. 

In addition to age-related changes in ventricle size, the BDR researchers also examined people with traumatic brain injury (TBI). TBI and dementia share many of the same signs, symptoms, and physiological features, such as enlarged ventricles. 

The researchers’ analysis showed that time lag in blood drainage did relate to TBI, but importantly, this effect depended on the age at which one suffered their injury. The group observed a rather large effect in those, who suffered TBI while young and a much less pronounced effect among those, whose injury occurred later in life. 

This technique could prove especially valuable among the TBI population, as many afflicted individuals are asymptomatic and therefore easily overlooked.

Although the method must still undergo further clinical testing before becoming eligible for use in a hospital setting, it has the advantages of being non-invasive, simple, and relatively inexpensive.