Motor and somatosensory conduction in cervical myelopathy and radiculopathy

Study Design.Motor and sensory conduction times were measured in patients with cervical myelopathy and radiculopathy. The results were compared with those of control subjects. Objective. To evaluate the clinical value of the combined use of motor-evoked potentials with F wave recording and somatosensory-evoked potentials in cervical myelopathy and radiculopathy. Summary of Background Data. Electromyography and somatosensory-evoked potentials provide only indirect information on the motor pathways. The development of magnetic transcranial stimulation has provided a direct and reliable physiologic insight into the motor system. Methods. Magnetic stimulation of the motor cortex and nerve roots with F wave recording was used to assess central and peripheral motor conduction times. Somatosensory conduction was evaluated by somatosensory-evoked potentials. Results. Significant prolongation of the central sensory and motor conduction times was found in the group with myelopathy. These findings were much more pronounced in patients who had multiple level spondylotic stenosis of the spinal canal than in those harboring a single disc herniation compressing the spiral cord. In Contrast to somatosensory-evoked potentials, motor-evoked potentials combined with F wave recording showed marked Impairment of peripheral conduction. In patients with radiculopathy. Conclusion. Motor-evoked potentials associated with F wave recording was suitable for the evaluation of patients with radiculopathy, The severity of conduction impairment in patients with myelopathy can be assessed by combined motor-evoked potentials and somatosensory-evoked potentials.