White matter hyperintensities in cholinergic pathways are associated with dementia severity in e4 carriers but not in non-carriers.

Carriers and non-carriers present distinct associations between dementia severity and WMHs in cholinergic pathways. In e4 carriers, increased white matter in cholinergic pathways are associated with greater dementia severity. In non-carriers, WMHs exhibit less predictive roles for clinical dementia severity. WMHs on the cholinergic pathway may have a different impact on e4 carriers vs. non-carriers.