Prognostic value of electrodiagnosis in the Dutch Guillain-Barré study

In the Dutch Guillain-Barré trial, three EMGs were performed according to a rigid protocol at early stages of the disease in 147 Guillain-Barré patients who were unable to walk independently. Independent locomotion 8 weeks and 6 months after entry were considered to be the outcome measures of most clinical value. Electrodiagnostic data obtained 1 week after entry were concluded to be most important for studying prognostic value. This has been attributed to the fact that 87% of the patients were in the nadir of their disease at that moment In univariate analysis, CMAP amplitudes of thenar and hypothenar muscles obtained after distal and proximal stimulation, as well as the recruitment pattern on maximal voluntary effort in these tested muscles, were significant predictors for outcome 8 weeks and 6 months after entry to the study. Motor nerve conduction velocity and distal motor latencies of ulnar and median nerves were weak predictors for outcome at 8 weeks after entry. In multivariate analysis the hypothenar CMAP amplitude on distal stimulation and recruitment pattern of abductor digiti minimi muscle both had an independent predictive value for independent locomotion 8 weeks after entry.