Dynamic changes in glymphatic-related imaging markers across acute sleep deprivation and recovery in healthy young adults

Sleep deprivation (SD) is widespread in healthy young adults, yet its effects on the glymphatic system (GS) and GS recovery post-sleep recovery (SR) remain unclear. In this study, we investigated the alterations of glymphatic-related MRI markers in 32 healthy young adults under three states: normal sleep (NS, 8 h overnight sleep), SD (24 h awake), and SR (8 h sleep post-SD), and did MRI scanning between 7:00-8:00 a.m. to minimise diurnal variations. Five markers-choroid plexus volume [CPvol], perivascular space [PVS] volume, white matter free water fraction [FW-WM], diffusion tensor imaging analysis along perivascular space [DTI-ALPS] index, and global Blood Oxygen Level Dependent-Cerebrospinal Fluid [gBOLD-CSF] coupling (in a subset of 12 participants)-were evaluated. Results showed the DTI-ALPS index was significantly lower in the SD group than in the NS group, and higher in the SR group, but cannot be totally recovered to baseline. FW-WM and gBOLD-CSF coupling were higher in SD than NS, and lower in SR than SD, but with no significant difference between SR and NS. Notably, PVS volume and CPvol showed no intergroup differences. A robust negative correlation between DTI-ALPS_mean and FW-WM was confirmed by repeated-measures correlation. This study showed that acute SD induces changes in specific glymphatic-related MRI markers, effects that are largely reversed by SR. DTI-ALPS, FW-WM, and gBOLD-CSF coupling may serve as sensitive markers for acute SD, while FW-WM and gBOLD-CSF coupling are sensitive to SR.