Somatosensory and motor cortical evoked potentials in the diagnosis and management of scan-negative myelopathy.

BACKGROUND

Radiology, particularly MRI, is critical for the diagnosis and timely management of spinal cord injury. In 20–25% of patients with clinical signs of myelopathy MR imaging is normal; this can be challenging diagnostically and delay the instigation of life-changing therapeutic interventions. Investigations that specifically probe the physiology of spinal white matter tracts, both the ascending pathways (somatosensory evoked potentials; SEPs) and descending pathways (motor cortical evoked potentials; MEPs), could provide additional information but their application in this context has not been widely reported.

OBJECTIVE

To explore the utility of MEPs/SEPs in both the diagnosis and management of MRI-scan-negative myelopathy, particularly MRI-negative acute inflammatory myelopathy.

METHODS

Review of referrals made between 2021 and 2023 to the clinical neurophysiology department at a regional clinical neuroscience unit in the UK. Extraction and review of case records of those with normal initial/acute neuroimaging referred for neurophysiologic investigation of suspected spinal myelopathy.

RESULTS

We describe the clinical presentation, clinical course and neurophysiology in six patients who presented between 2021 and 2023 with MRI-scan-negative myelopathy. All had abnormal MEPs and SEPs. Five of six cases were subsequently diagnosed with inflammatory myelopathy.

CONCLUSION

These cases illustrate the important role MEPs and SEPs play in diagnosing and managing MRI-scan-negative myelopathy.