FVC-DiP correlates with neurofilament light chain levels in serum and cerebrospinal fluid in patients with ALS.

We previously reported a scale to assess the disease progression rate in patients with amyotrophic lateral sclerosis (ALS), the forced vital capacity decline pattern scale (FVC-DiP). In this study, we investigated the association between FVC-DiP scores and neurofilament light chain (NfL) in the serum and cerebrospinal fluid (CSF) in patients with ALS. We performed a retrospective study to examine the association between NfL levels and the rate of disease progression (N=41). The disease progression rate was assessed using three

Methods: the FVC-DiP score determined using the percentage of predicted FVC (%FVC) and disease duration at the %FVC measurement, the rate of decline in the ALS Functional Rating Scale Revised (ALSFRS-R) score (ΔFS) and the rate of decline in the %FVC (Δ%FVC). The FVC-DiP scores were significantly correlated with NfL levels in both the serum and CSF (serum, R2=0.274, p<0.001; CSF, R2=0.274, p=0.001). Patients assessed as rapidly progressing by the FVC-DiP had high NfL levels, and patients assessed as slowly progressing had low NfL levels. In the group with a low ΔFS and/or Δ%FVC, although the disease progression rate assessed by the FVC-DiP may have differed from the assessments obtained using the ALSFRS-R and/or %FVC, the correlation between FVC-DiP scores and serum NfL levels remained consistent. The FVC-DiP was significantly associated with NfL levels in the serum and CSF, suggesting that the FVC-DiP is a reasonable scale to assess the rate of ALS progression.