The electrophysiology of axonal and demyelinating polyneuropathies

Electrodiagnostic studies, which include nerve conduction studies, electromyography, repetitive nerve stimulation, single fibre EMG, autonomic function tests and quantitative sensory tests are a critical component of the neuromuscular evaluation. These studies, which are an extension of the clinical examination, help to classify further patients into the part of the peripheral nervous system affected and provide significant insight into the pathophysiological processes that underlie clinical illnesses. Traditionally, patients with peripheral neuropathy are classified as having demyelinating or axonal neuropathies. The methods of making this distinction are discussed. In addition, a number of additional studies are now available which provide further, insights into selected aspects of the peripheral nervous system.