A Case of Auditory Neuropathy Caused by Pontine Hemorrhage in an Adult

Abstract

A pontine hemorrhage can evoke several neurological symptoms because the pons contains various nuclei and nerve fibers. Hearing loss can develop as a result of a pontine hemorrhage because there is an auditory conduction pathway in the cochlear nucleus of the pons. However, very few cases of hearing loss caused by pontine lesions have been reported, and there have been no reports of auditory neuropathy that developed following a pontine hemorrhage. Recently we had a patient who experienced a nontraumatic pontine hemorrhage who was diagnosed with auditory neuropathy. The 34-year-old male patient was admitted to the emergency department with sudden alteration of mental status. His brain computed tomographic imaging revealed a hemorrhage in the central pons. He complained of hearing difficulties after his mental status recovered through conservative treatment, but a pure-tone audiogram showed very mild hearing loss in both ears. Further hearing tests using otoacoustic emissions, which showed normal responses, and auditory brainstem responses, which showed no waveforms at maximum stimulus intensity, revealed that his hearing difficulties were caused by auditory neuropathy. This case implies that the threshold of sound detection can be preserved in patients with pontine hemorrhage who complain of hearing difficulties. Auditory neuropathy should be considered as a possible cause of hearing difficulties in these patients and appropriate hearing tests should be performed.

Acute onset bilateral hearing loss in dorsomedial pontine hemorrhage

“…With regard to etiology, Kim et al proposed that the pontine hematoma injured the bilateral cochlear nuclei and trapezoid body, [10] while Chung et al reported that the hematoma and surrounding edema compressed the bilateral cochlear nuclei. [9] Compared to previous reports, the present case was characterized by the small hematoma volume and the absence of concurrent disturbance of consciousness at hemorrhage onset. Furthermore, in the present patient, bilateral hearing loss began on the day of hospital admission, which is earlier than in previous reports (Table 2).…”

“…However, in cases of major hemorrhage that extends across the bilateral cochlear nuclei, hearing loss accompanied by disturbance of consciousness due to damage to the reticular formation may occur. [9] In such cases, disturbance of consciousness is likely to prevent patients reporting the hearing loss.…”

Sudden Hearing Loss and Vertigo With Silent Pontine Infarction: A Case Report

“…In specific, various forms of hearing loss have been reported in cases of pontine infarction. Bilateral hearing loss has been documented, as well as cases where hearing loss occurs on the opposite side of the pontine infarction according to central auditory pathway [6,12,13,15]. In addition, cases of hearing loss associated with pontine lesions have been reported to exhibit characteristics similar to auditory neuropathy spectrum disorder, where OAE are present but auditory brainstem response is absent, indicating preserved cochlear function [15].…”

“…Bilateral hearing loss has been documented, as well as cases where hearing loss occurs on the opposite side of the pontine infarction according to central auditory pathway [6,12,13,15]. In addition, cases of hearing loss associated with pontine lesions have been reported to exhibit characteristics similar to auditory neuropathy spectrum disorder, where OAE are present but auditory brainstem response is absent, indicating preserved cochlear function [15]. In this case, the patient presented with silent pontine infarction, exhibiting ipsilateral hearing loss and dizziness, without any other neurological symptoms.…”