Pre-existing neurological disorders such as multiple sclerosis (MS), peripheral neuropathy, and myopathies significantly impact neuromonitoring during anesthesia, making it essential for anesthesia providers to understand these effects for accurate intraoperative assessment.
Multiple sclerosis (MS) is characterized by demyelination and chronic inflammation in the central nervous system, disrupting the conduction of electrical impulses along affected nerves and causing neuronal damage. This leads to prolonged latency and reduced amplitude in somatosensory evoked potentials (SSEPs), making it challenging to detect new changes during surgery. Motor evoked potentials (MEPs) in MS patients may also show increased latency and decreased amplitude, reflecting impaired motor pathway conduction.
Peripheral neuropathy involves axonal degeneration and, in some cases, demyelination of peripheral nerves, leading to decreased amplitude and increased latency in SSEPs and MEPs. Myopathies involve structural and functional abnormalities in muscle fibers and neuromuscular junction dysfunction. Because the sensory pathways are spared, SSEPs are typically preserved; muscle-recorded MEPs, however, show reduced amplitude and can be significantly degraded.
