NEFL and Atrophy: However, serum NfL levels were correlated with rates of whole brain (r = 0.46, p = 0.01), frontal lobe (r = 0.53, p = 0.003; figure 2), and parietal lobe (r = 0.38, p = 0.04) atrophy, although not with other lobar atrophy rates.