Finally, we investigated whether the relationships between LC intensity and nocturnal awakenings are modified by plasma AD biomarkers, and found that the negative relationship between middle-to-caudal LC intensity and nocturnal awakenings was particularly evident in individuals with higher levels of total tau (F1,61 = 4.23, p = 0.04, R2β* = 0.06, Fig. 3, Table 3). This evidence concerns the gene MAPT and Alzheimer disease.