Somatosensory evoked potentials (SEP)

Somatosensory evoked potentials (SEP) explore the lemniscal sensory pathway (the pathway of deep sensation and fine touch) in its entirety, from the peripheral nerves to the parietal cortex. The examination consists of electrically stimulating a peripheral nerve (usually the median nerve at the wrist or the posterior tibial nerve at the ankle) and recording the responses at different levels along the sensory pathways. The upper-limb SEP (median nerve stimulation) record responses at the level of the brachial plexus (Erb's point), the cervical spinal cord, the brainstem and the parietal cortex. The lower-limb SEP (posterior tibial nerve stimulation) explore the sensory pathways from the cauda equina to the parietal cortex, passing through the spinal cord. This examination is particularly indicated in the assessment of cervical and thoracic myelopathies, spinal cord compressions, multiple sclerosis and brainstem lesions. It is also used intraoperatively for the monitoring of the spinal cord during high-risk spinal surgeries. The Clinique Pasteur in Tunis carries out SEP according to international recommendations, allowing a complete and reliable exploration of the somatosensory pathways. The examination is often coupled with VEP and AEP to make up a multimodal assessment of the evoked potentials.