Quinn C, et al. - Given the need for a reliable clinical evaluation of upper motor neuron (UMN) findings in order to validate biomarkers of UMN impairment in amyotrophic lateral sclerosis (ALS), and the Penn Upper Motor Neuron Score (PUMNS) represents a standardized measure of UMN signs in ALS, researchers assessed its intra- and interrater reliability as well as evaluated inter-item reliability as a substitute for item relatedness and scale efficiency. During routine clinic visits, study procedures were done. They used Pearson's correlation coefficient and Cronbach's alpha to calculate intra and inter-rater reliability and inter-item reliability, respectively. High intra and inter-rater reliability of PUMNS was revealed in this study. Total and sub-score correlation coefficients were all ≥ 0.96. The inter-item reliability showed appropriate item relatedness with reasonable efficiency and sub-score correlation coefficients between 0.68 and 0.85. Experts concluded that UMN signs in ALS can be reliably measured using the PUMNS and it would afford a valuable instrument in validating imaging and laboratory biomarkers of UMN injury in ALS.