The electrodiagnostic evaluation of nerve root function.

Electrodiagnostic testing is an important part of the investigation of spinal nerve root and cord function. These tests are utilized to confirm and document suspected neuronal lesions. Characteristics of a spinal nerve root lesion, including chronicity, level, sensory or motor dysfunction, and severity, can be estimated by utilizing multiple testing procedures. Tests available include needle electromyography. H-reflexes, F-responses, bulbocavernosus reflex responses, and somatosensory evoked responses recorded over the spine and head. Each test has unique advantages and disadvantages and none can be considered of sufficient sensitivity to exclude the other tests. By using case examples the lack of correlation between electrodiagnostic testing and spinal pain has been illustrated.