Reliable and efficient scale to assess upper motor neuron disease burden in amyotrophic lateral sclerosis

Background Validation of biomarkers of upper motor neuron (UMN) impairment in amyotrophic lateral sclerosis (ALS) requires a reliable clinical assessment of UMN findings. The Penn Upper Motor Neuron Score© (PUMNS) is a standardized measure of UMN signs in ALS. Our aims were to evaluate its intra‐ and inter‐rater reliability, and to examine inter‐item reliability as a proxy for item relatedness and scale efficiency. Methods Study procedures were performed during routine clinic visits. We calculated intra and inter‐rater reliability using Pearson's correlation coefficient and inter‐item reliability using Cronbach's alpha. Results PUMNS had high intra and inter‐rater reliability. Total and sub‐score correlation coefficients were all ≥0.96. The inter‐item reliability indicated appropriate item relatedness with reasonable efficiency and sub‐score correlation coefficients between 0.68 and 0.85. Conclusions PUMNS is a reliable measure of UMN signs in ALS and would be a useful tool in validating imaging and laboratory biomarkers of UMN injury in ALS. See editorial on pages 431–432 in this issue.