The brain lacks specialized vessels and pumping structures to circulate the fluids that it needs to survive. Instead it relies on the motion of arterial blood from the heart to circulate cerebrospinal fluid (CSF). CSF bathes the brain and spinal cord and delivers vital nutrients and, most importantly, removes the waste products generated by the brain’s metabolism. If these are not cleared they can build up to form plaques.
The movement of CSF around the brain compensates for the changes of pressure within the skull produced by variable blood flow/pressure during each cardiac cycle. Yet this on its own is not enough – the cranium itself must also subtly expand and contract in response to these changes in pressure in order for the system to work effectively. These three elements (blood flow, circulation of CSF, and the biomechanical properties of the skull) make up the concept of Cranial Compliance (CC) which seeks to measure how these fluids along with the pliability of the skull interact, and whether this system is functioning normally.
Both CSF circulation and CC have also been studied using magnetic resonance imaging technologies (MRI). However, these studies have had a greater focus on the structural elements of the cranial system, whereas our studies have had a greater focus on the functional elements of the interaction of these systems. The focus of our research over the last two years has been to investigate the many factors that can affect CC and how its fluctuations relate to changes in cognitive functioning.
As well as developing an accurate way of calculating CC, the Beckley Foundation/Moskalenko work has investigated the effects of ageing on CC. The results show that as we age our craniums lose the ability to expand and contract, and therefore we are more likely to suffer from deficiencies in CC. This in turn leads to a decrease in CSF flow, which may cause a build-up of toxins in the brain. Hence reduced CC may account for at least some age-related cognitive decline.