GUILLAIN-BARRE-SYNDROME - CLINICAL NEUROPHYSIOLOGIC STUDIES

Guillain-Barre syndrome is a well-defined clinical entity correspondin g to primary inflammatory demyelinating lesions of peripheral nerves a nd spinal roots in the majority of cases seen in Western Europe and No rth America. Documentation of conduction abnormalities characteristic of demyelination in the context of rapidly developing weakness confirm s the clinical diagnosis of acute inflammatory demyelinating polyradic uloneuropathy. These abnormalities include(1) conduction block, (2) ma rkedly prolonged distal latencies, (3) marked slowing of motor conduct ion velocities, and (4) absent or impersistent F responses. Other abno rmalities are of ambiguous significance : (1) low amplitude compound m uscle responses, (2) absent sensory nerve potentials, (3) reduction in the maximum EMG recruitment pattern, which may all (1, 2, and 3) indi cate conduction block or axonal degeneration, and (4) fibrillation pot entials due to breakdown of motor axons, a frequent non-specific effec t of primary inflammatory demyelination, A Guillain-Barre va riant due to immune-mediated primary axonal degeneration has also been recently described.