Attempts to increase the diagnostic yield and reproducibility of electrophysiological investigation of peripheral nerve disorders have led to the development of new techniques, such as measurement of nerve refractoriness, as well as the re-evaluation, refinement and modification of more conventional nerve conduction tests. Other studies have characterized the clinical and electrophysiological features of the subtypes of polyneuropathies associated with monoclonal gammopathies and have documented their natural history, providing important diagnostic and prognostic information. Techniques originating in basic neuroscience that study the excitability of neurons and nerve membranes have been applied to clinical conditions, such as motor neuron disease and cramps, and have provided considerable insight into their pathogenesis.