The focus of our project is on electrophysiology in Guillain-Barré Syndrome (GBS), utilizing data from the International Guillain-Barré Syndrome Outcome Study (IGOS). Despite extensive research over the past decades, several crucial questions remain unanswered. For instance, what is the exact role of electrophysiology in GBS? Does electrodiagnostic subtyping provide any prognostic information for patients? Given the large cohort of patients in IGOS with long-term follow-up data and the availability of several factors such as ganglioside antibodies, preceding infections, and clinical data, we aim to address these questions.