What indicates significant changes in cervical and cortical SSEPs during IONM?

Significant changes in cervical and cortical somatosensory evoked potentials (SSEPs) during intraoperative neuromonitoring (IONM) are typically indicated by an absence of changes in peripheral responses. This is because the peripheral response serves as a baseline measure of the functional integrity of the sensory pathway from the peripheral nerves to the cortex. If there are significant alterations in the central responses (i.e., cervical and cortical SSEPs) while the peripheral responses remain stable, it suggests that there may be an issue occurring in the central nervous system pathways themselves, such as the spinal cord or brain.

In this context, when evaluating SSEPs, clinicians are keenly aware that any variation in latency or amplitude of the evoked responses can provide critical information about potential neurological compromise. However, for these changes to be significant, it is essential that the peripheral components remain unchanged; this highlights that any observed changes in cortical or cervical responses are due to central pathology rather than peripheral factors.

Consequently, the other options, which address latency, amplitude, and motor fiber excitability, do not provide the same level of insight regarding the central versus peripheral distinction necessary to understand significant changes in SSEPs during IONM.