Test-retest reliability of coupling between cerebrovascularoscillations and cerebrospinal fluid flow fluctuations

Motivation: The coupling strength of global blood-oxygen-level-dependent (gBOLD) signals and cerebrospinal fluid (CSF) inflow have been suggested to be an indicator of glymphatic system function. However, few studies have validated its test-retest reproducibility. Goal(s): To assess the reproducibility of gBOLD-CSF coupling. Approach: Thirteen adults of the sleep deprivation (SD) group and 14 adults of the control group underwent three fMRI. The reliability of gBOLD-CSF coupling was evaluated by the intraclass correlation coefficient (ICC). Results: A higher ICC (0.525, P = 0.001) was observed in the control group compared with the SD group (0.137, P = 0.086). Impact: The gBOLD-CSF coupling shows good reproducibility, but care should be taken when interpreting longitudinal changes of the gBOLD-CSF coupling that may be influenced by participants’ drowsiness. Sleep should be considered an important factor in future studies exploring the glymphatic system.