Prospective Validation of the New <scp>PLS</scp> Diagnostic Criteria From <scp>PLS</scp> Natural History Study: <scp>EMG</scp> and Neurofilament Analyses

In our population, reclassification of PLS to ALS occurred at a low frequency at 1 year follow-up (7.1%). Baseline NfL was the strongest predictor in differentiating UMN dominant ALS from PLS at 1-year follow-up. Based on our data, we propose EMG and NfL criteria for enrollment in future PLS trials.