[Electrodiagnosis of focal neuropathies]

Electrodiagnostic techniques used in an EMG-Laboratory and the diagnostic value in focal mononeuropathies are presented. The electrodiagnostic techniques include nerve conduction studies and needle electrode examination. Measurement of distal latency, amplitude, conduction velocity and the finding of focal conduction block may localize the focal character of the mononeuropathy. The needle electrode examination gives further information about distribution, extent, activity, or chronicity of the disease, especially in cases with axonal injuries. Some normal electrodiagnostic patterns are presented, accompanied by some illustrative pathological cases.