In cases of severely elevated ICP, which modalities remain unaffected?

Mid-latency auditory responses and cortical somatosensory evoked potentials (SSEPs) tend to remain unaffected in cases of severely elevated intracranial pressure (ICP) due to their pathways being less reliant on the brainstem and deep structures that might be impacted by high ICP. These responses involve cortical processing and can continue to be recorded even in challenging conditions, such as elevated ICP, where other modalities may demonstrate significant changes or loss of amplitude.

Cortical SSEPs are generated in the cortex following peripheral nerve stimulation and are reflective of cortical function, which can be preserved until ICP reaches critical levels that affect general brain function. Mid-latency auditory responses, generated within the auditory cortex, are less susceptible to immediate influences of elevated ICP due to similar reasons related to their cortical origins.

Understanding the pathways and anatomical locations involved in generating these responses helps clarify why they may remain stable despite significant changes occurring due to elevated ICP, whereas other modalities may experience alterations or diminished signals under such conditions.