Cervical radiculopathy for neurologists: the role of electrodiagnosis

Cervical radiculopathy (CR) is a common condition encountered in the general population, usually related to a musculoskeletal degenerative condition. Conventional electroneuromyography (ENMG) consists of nerve conduction studies (NCS) and needle electromyography (EMG), and it is regarded as the most specific diagnostic evaluation in this scenario. Although CR is commonly encountered in clinical practice, ENMG as a diagnostic tool is not often discussed in neurology residency programs. Electromyography has demonstrated modest sensitivity (50-71%) but excellent specificity (approaching 100%) for the diagnosis of CR. It can also provide valuable information about lesion chronicity. In EMG, acute lesions typically present with denervation potentials and reduced recruitment, but with preserved motor unit action potential (MUAP) morphology. In contrast, chronic lesions are characterized by remodeling, with MUAPs showing increased duration, amplitude, and number of phases, in addition to reduced recruitment. The present review aims to provide an overview of the roles of NCS and EMG, while also introducing key terminology commonly encountered in the interpretation of these diagnostic modalities.