Early Electrophysiology in Suspected Acute Guillain-Barré Syndrome: A Prospective Study of Comprehensive Testing.

Purpose: Electrophysiologic changes in early Guillain-Barré Syndrome (GBS) can be nondiagnostic. Improved testing paradigms may improve hyperacute treatment.

Methods: This work prospectively evaluated consecutive patients admitted to a metropolitan teaching hospital in Melbourne, Australia, with suspected acute GBS. We performed extensive neurophysiology at three different time points. Novel tests, including cutaneous silent periods, long latency reflexes, and contraction-induced H reflexes, were assessed.

Results: Twenty-three participants were studied, including 13 cases of acute GBS. In total, 69% of acute cases of GBS were accurately diagnosed on the first nerve conduction study using published neurophysiologic criteria, with serial studies rarely altering the GBS subtype classification. Antidromic and orthodromic upper limb sensory studies were diagnostically equivalent. A sural sparing pattern was seen in 77% of cases of GBS at the first test. Long latency reflexes and contraction-induced H reflexes testing were abnormal in most participants but were limited by muscle weakness in some. Cutaneous silent periods testing was unobtainable in approximately 50% of cases because of weakness and did not discriminate from mimic disorders.

Conclusions: Abnormalities of long latency reflexes and contraction-induced H reflexes may be helpful where initial electrophysiology is nondiagnostic but are nonspecific. Cutaneous silent periods testing seems of limited value. Comprehensive testing provides diagnostic certainty in most cases of GBS from the very first study.