Abnormal BAEP and internal auditory canal MRI in intracranial hypotension

Intracranial hypotension (IH) is a treatable condition due to cerebrospinal fluid leak, characterized by variable clinical and MRI findings.Positional headache, neck stiffness, hearing changes with subdural fluid collection, enhancement of meninges, engorgement of venous structures and brain sagging are among the most frequent clinical and MRI findings. Typical abnormalities are found in 68%–85% of patients. Hearing alterations (ranging from misperception to severe hearing loss) are known clinical symptoms of IH. The mechanism involves secondary perilymph depression due to patency of the cochlear aqueduct, inducing a compensatory expansion of the endolymphatic compartment, decreasing basilar or Reissner’s membrane compliance. Some reports showed internal auditory canal (IAC) MRI abnormalities in IH. As brainstem acoustic evoked potentials (BAEPs) track internal ear structure and brainstem acoustic pathways integrity, we assessed possible BAEP abnormalities in IH. In order to improve IAC imaging we performed contrast-enhanced spectral adiabatic inversion recovery (SPAIR) 3T MRI in each patient with IH.