Although physiologic measures demonstrate normal peripheral hearing sensitivity, this patients speech has the inflection and prosodic characteristics associated with profound peripheral hearing loss, and she is unable to understand spoken communication. Behaviorally obtained pure-tone thresholds were variable, ranging from normal to moderate hearing loss with normal middle ear muscle reflexes and normal ABRs to high- and low-intensity stimuli. Auditory middle latency and cortical evoked potentials were grossly abnormal, consistent with the central nature of cortical deafness. Because of her inability to communicate auditorily, this patient was ultimately taught American Sign Language and educated at the Louisiana School for the Deaf. At the completion of the case study, the patient was married and expecting a child. A more recent study, published in 2013 the patient described is a 56-year-old woman a history of hypertension, hypercholesterolemia, and multiple cerebrovascular accident (CVA) who presented in March 2009 with a complaint of complete bilateral hearing loss. In March 2009, she experienced an acute right-sided insulotemporal intracerebral hemorrhage. Immediately after this event, the patient complained of hearing loss with the inability to hear all sounds except for severe bilateral tinnitus. Imaging revealed sequelae in the left cerebral cortex from her previous CVA. The new right-sided hemorrhage was centered on the posterior putamen with surrounding edema involving the posterior portion of the posterior limbs of the internal, external, and extreme capsules. Signal abnormalities extended into the right temporal lobe. The patient had no other neurologic deficits and spoke fluently, although with poor internal volume control of her voice.
The following are three case studies with different reasons for cortical deafness. A case published in 2001 describes the patient as 20-year-old man referred for cochlear implants because of bilateral deafness following a motorcycle accident two years earlier. His CT shows hemorrhagic lesions involving both internal capsules. He was comatose for several weeks and awoke quadriparetic, cognitively impaired and completely deaf. He exhibited a response towards the occasional sudden, loud sound, however, by turning his head. Reading and writing capabilities were maintained, and he was able to communicate by lip-reading. His own speech was dysarthric, but comprehensible. Normal tympanograms and stapedial reflexes imply that the middle and inner ear remained functioning and the auditory nerve was intact. His auditory nerve was tested by evoking responses with normal auditory nerve potentials at 10 dB bilaterally. The results of the BAER waves were normal, but an abnormal complex IV-V suggested that the pathways were functioning through the brainstem, but there was a lesion present in the mid-brain. With these findings, it was determined the patient had cortical deafness due to bilateral interruption of the ascending auditory pathway associated with hemorrhagic lesions of both internal capsules. Therefore, cochlear implantation was not performed. Published in 1994, this patient was monitored over the course of almost 20 years after exhibiting signs of hearing impairment as an infant. Audiologic and related test results in concurrence with MRI confirmed bilateral absence of considerable portions of her temporal lobes resulting in cortical deafness.