Which abnormality may be associated with vascular malformations of the posterior fossa alongside hemifacial spasm and facial paresis?

BAER latency abnormalities can indeed be associated with vascular malformations in the posterior fossa, as these malformations can exert pressure on the cranial nerves and brain structures, thereby affecting auditory pathways. In particular, the presence of hemifacial spasm and facial paresis indicates that the facial nerve is being impacted, which can lead to delayed neural conduction in the brainstem where the auditory pathways are located.

When there is increased pressure or vascular compression in areas such as the cerebellopontine angle, latency abnormalities in the Brainstem Auditory Evoked Responses (BAER) can manifest due to disrupted neural conduction. These abnormalities typically present as increased latencies on the waveforms, reflecting that the signals from the auditory nerve take longer to reach the auditory cortex.

Understanding this connection is crucial in neurophysiologic intraoperative monitoring, where identifying abnormalities can guide surgical teams in avoiding complications related to vascular malformations and nerve injuries.