Radiculopathy and Motor Neuron Disorders

Abstract

Although radiculopathies and motor neuron disorders have vastly different underlying mechanisms and clinical presentations, the electrodiagnostic examination for these disorders demonstrate remarkable similarities. In all of these conditions, the electrophysiological examination reflects motor neuron injury with virtually no involvement of sensory neurons, even in the face of substantial sensory symptoms, as may occur in radiculopathy. The needle examination is a critical part of electrophysiological testing, helping to define the extent and severity of the abnormality, often more effectively than is possible with nerve conduction studies alone. Late responses, including F-waves and the H-reflexes, can also assist in the diagnosis of radiculopathy to some extent. The electrodiagnostic evaluation of motor neuron disease requires special consideration and care.