Sensory Neural Hearing Loss
Sensory neural hearing loss is the most common type of hearing loss in adults. It occurs through degradation or damage to the outer and inner hair cells of the cochlea. Noise, chemical changes, and the natural aging process can all cause damage to the sensory cells, which results in a decrease in perceived volume and decreased clarity.
Diagnosis: A sensory hearing loss can be diagnosed with an audiometer and otoacoustic emission testing. A healthy cochlea emits measurable sounds when stimulated. If the sounds are absent or reduced, it suggests damage to the outer hair cells.
Treatment: Damage to the hair cells of the cochlea cannot usually be treated with medication or surgery. In some sudden-onset cases, steroids may be used to revive the cells. Typically, however, the treatment is hearing aids.
VIIIth Nerve Tumor
Once the auditory stimulus makes its way through the ear, it travels along the VIIIth cranial nerve to the brainstem and then up to the brain for processing. Sometimes, the ear may be healthy, but a significant hearing loss is caused by damage to the nerve itself. The most common type of neural hearing disorder is caused by a tumor on the VIIIth cranial nerve.
Diagnosis: Auditory brainstem response testing (ABR) is frequently used to rule out the presence of an VIIIth nerve tumor. However, an MRI is the gold standard. Suspicion of an acoustic tumor occurs when it manifests itself as a unilateral hearing loss, often accompanied by tinnitus and dizziness
Treatment: VIIIth nerve tumors are slow-growing and benign. Depending on the size, a physician may choose to simply monitor its growth. Tumors can also be removed surgically, but with significant risk to the auditory nerve. Hearing aids may also be helpful.
Auditory Processing Disorder
Without the brain, it is impossible to hear. The signal from the ears must be interpreted by the brain in order to be comprehended. In some cases, more often in smaller children, the auditory portion of the brain does not properly utilize the signals delivered by the ear. This is known as an auditory processing disorder
Diagnosis: Auditory processing disorders are typically diagnosed through a serious of audio test which evaluate the ability to understand in difficult situations, such as in the presence of competing sounds. Testing is time-intensive and may be accompanied by electrophysiological tests such as the ABR.
Treatment: Auditory processing disorders are most often treated by utilizing effective communication strategies. In the case of children, preferential seating and other accommodations at school may be warranted. In some listening situations, listening devices may be helpful.