Which monitoring modality is most likely to be affected by a large bolus of muscle relaxant?

The correct answer is myogenic evoked potential (MEP), as this modality directly depends on the integrity of the muscular system to produce measurable motor responses. MEPs evaluate the electrical responses of muscles following stimulation of the motor cortex and can be significantly affected by the administration of muscle relaxants. These agents interfere with neuromuscular transmission at the neuromuscular junction, which, in turn, reduces the amplitude or abolishes the motor response that MEPs rely on for assessment.

In contrast, cortical somatosensory evoked potentials (SSEP) measure the electrical activity in the brain following sensory stimulation and are generally less influenced by muscle relaxants since they depend on the central nervous system rather than peripheral muscle activity. Brainstem auditory evoked responses (BAER) reflect auditory pathways up to the brainstem and remain unaffected by muscle relaxants, as they are not reliant on muscle function. Neuromuscular evoked potentials (NMEP) can be influenced by muscle relaxants, but they are not as directly impacted as MEPs when considering large boluses, because NMEPs are primarily assessing the neuromuscular junction rather than direct muscle responses. Thus, MEPs are the modality most likely to be