Clinical and electrophysiological assessments in ALS patients.

Since the relationships between traditional assessments in ALS patients have not been defined, three clinical and four electrophysiological assessments were performed in a cross-sectional study of 87 ALS patients. The clinical assessments produced Norris ALS scores, muscle strength scores and illness durations (DUR). The electrophysiological assessments produced scores for motor unit interference pattern, denervation potentials, compound muscle action potential, and fasciculations. The individual muscle scores were averaged to produce mean scores, and Spearman rank correlations were performed on the mean scores. The association between Norris ALS and mean muscle strength (MMS) scores is significant (p less than .001, rs = 0.84), and these scores are significantly correlated with mean interference pattern (0.77, 0.82), mean denervation potential (-0.63, -0.70), and mean compound muscle action potential scores (0.55, 0.60), respectively. Correlations between IP and DP scores (-0.71), IP and CMAP scores (0.62), and DP and CMAP (-0.56) scores are also significant. Scatterplots of the data and regression lines suggest linear relationships between each of these assessments. Illness duration and fasciculation scores are not strongly correlated (rs less than 0.55) with any of the other clinical or electrophysiological assessments.