Meanwhile from Dr. Beggs...
this was published in May of this year.
Venous flow in the neck is the strongest predictor of the aCSF pulse.
The cerebrospinal fluid (CSF) pulse in the Aqueduct of Sylvius (AoS) (the aqueductal CSF (aCSF) pulse) is closely linked with the motion of the lateral ventricles  and can be used as a surrogate measure of brain tissue ‘stiffness’
The dynamics of the aCSF pulse are an issue of clinical importance. Increased amplitude of the aCSF pulse has been shown to be associated with MS [3,4,5,6,7], NPH [8,9,10,11,12,13], and early-stage WM changes [14,15]. However, the mechanism linking aCSF pulse dynamics with these pathologies is poorly understood. Because the phenomenon has been linked with an increase in the ‘stiffness’ of the brain tissue , it may be that increased aCSF stoke volume is a sign that the cerebral windkessel mechanism [40,41,42], which regulates blood flow through the parenchyma, has become impaired . Impairment of the windkessel mechanism has been shown to occur with bilateral compression of the IJVs, resulting in increased pulsation in the pial arteries . This has been linked with WM changes in elderly individuals, with increased pulsatility in the parenchymal vascular bed associated with WM microstructural changes , small vessel disease  and leukoaraiosis . Increased aCSF stroke volume might also be associated with transependymal seepage of CSF into the parenchyma, reversing the normal direction of flow . Being a semipermeable barrier between the brain parenchyma and the CSF in the ventricles  the ependymal wall is vulnerable to disruption . Indeed, in NPH patients the periventricular tissue is characterized by disruption of the ependyma, and by oedema, neuronal degeneration, and ischemia . In patients with communicating hydrocephalus transependymal CSF resorption appears to be associated with caudal-to-cranial net aqueductal flow, whereas the direction is cranial-to-caudal in healthy individuals . Collectively, this highlights the need to better understand the dynamics of the aCSF pulse and its role as an indicator neurological well-being.