Diffusion tensor imaging along the perivascular space in healthy young adults is associated with decreased sustained attention: a preliminary study.

Diffusion Tensor Imaging Along the Perivascular Space (DTI-ALPS) is a noninvasive method often used to assess and quantify diffusivity along the perivascular space in predefined regions of the brain. Although it is frequently applied in clinical populations, its relationship with cognitive performance in healthy individuals remains poorly understood. This study examined whether DTI-ALPS index (hereafter ALPS index) values are associated with performance decrement during a sustained attention task in healthy young adults. Forty-two healthy right-handed participants underwent DTI scanning and performed a 25-minute psychomotor vigilance task (containing 5-minute long blocks) in an MRI environment. ALPS indices were computed separately for the left and right hemispheres. Intraclass correlation coefficients between the observers were calculated to assess interrater reliability. Performance changes during the vigilance task were quantified by mean reaction time (RT) changes between the first and last 5-minute-long blocks (B5–B1 difference) and RT slope across the 5-minute-long task blocks. The observer agreement for ALPS index was acceptable to excellent (0.754–0.902). Behavioral analyses confirmed a significant increase in RTs across the blocks (p < 0.001). Both left and right ALPS indices were significantly and inversely associated with RT increase (left: p = 0.002; right: p = 0.003) and RT slope (left: p = 0.003; right: p = 0.004), indicating that higher ALPS index values predicted greater resilience to cognitive fatigue. Our findings suggest that ALPS index is correlated with sustained attention performance in healthy individuals.