Polyneuropathies - neurophysiological diagnostic points

A survey of clinical neurophysiological methods of importance in the diagnosis of polyneuropathies is given. Electromyography (EMG) is essential and should be performed in all four extremities. If the EMG findings with concentric needle electrodes are equivocal, fibre density determination with single fibre electrodes can give useful information. The various methods of determining conduction velocities in motor and sensory nerve fibres are described. Recent advances in the examination of function in sensory fibres are presented, particularly microneurography and psychophysical methods. The applicability of the methods with regard to the age of the patient is discussed.