Neurofilament light chain level in cerebrospinal fluid can differentiate Parkinson's disease from atypical parkinsonism: Evidence from a meta-analysis

A reliable test that facilitates the accurate diagnosis of Parkinson's and disorders will help with both, clinical management and therapeutic research. In this context, neurofilament light chain (NFL) is candidate for a biomarker in cerebrospinal fluid (CSF). A comprehensive literature search yielded 4 eligible studies. We expressed between-group difference of NFL concentration in CSF as the standardized mean difference. Four studies involved 166 Parkinson's disease (PD), 116 multiple system atrophy (MSA) and 73 progressive supranuclear palsy (PSP) patients. Patients with MSA showed higher concentration of NFL concentration in CSF than those with PD (standardized mean difference = 1.60, P < 0.0001). These studies were homogeneous (P = 0.17). NFL in CSF in PSP was significantly elevated relative to PD with homogeneous studies (standardized mean difference = 2.04, P < 0.0001; P = 0.99). The present meta-analysis suggested that NFL concentration in CSF in MSA and PSP was significantly increased relative to PD, and that this could help us to separate PD from atypical parkinsonian syndromes.