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.