An acoustic neuroma is a tumor located on the nerve that supplies the inner ear. Unilateral acoustic neuromas are acoustic neuromas that only affect one ear. The tumor affects the eighth cranial nerve and is responsible for 7 percent of all tumors within the skull, states The Merck Manual. The tumor can expand and damage the fifth and seventh cranial nerves. The damage to these three nerves is the direct cause of the symptoms associated with acoustic neuroma.
Hearing Loss
Over 90 percent of patients with unilateral acoustic neuromas experience a gradual loss of hearing in one ear, according to Johns Hopkins Medicine. The hearing loss is caused by the tumor affecting the eighth cranial nerve. Hearing loss may be described as the inability to understand spoken words, particularly when using the phone. The hearing loss is usually gradual, but in 5 percent of cases of unilateral acoustic neuroma, the hearing loss is sudden. A medical professional should evaluate any hearing loss that is more noticeable in one ear.
Ringing in the Ears
A common symptom experienced by patients with acoustic neuroma is ringing in the one affected ear, reports the National Institute on Deafness and Other Communication Disorders. This ringing in the ear is called tinnitus. The ringing is heard as a high-pitched sound that is present even when there is no environmental noise. The tinnitus may be present with or without unilateral hearing loss. Tinnitus can be a symptom of any inner ear disease, but a physician should evaluate any unilateral ear ringing.
Dizziness and Impaired Balance
Dizziness and a difficulty balancing are common symptoms in patients with unilateral acoustic neuroma, according to The Merck Manual. This is due to the damaged eighth cranial nerve. The eighth cranial nerve is responsible for hearing and balance, and any damage to this nerve will impair these functions. The dizziness is usually only apparent during the early stages of the neuroma. As the disease progresses, the brain is able to adapt to the damaged nerve and compensate.
Facial Weakness and Numbness
Larger acoustic neuromas can cause facial weakness and numbness, states Johns Hopkins Medicine. Large unilateral acoustic neuromas can affect cranial nerves five and seven, which are in charge of facial sensation and movement. If these nerves are affected, patients can develop the inability to close the eyes properly, raise the eyebrows and wrinkle the forehead on the side of the acoustic neuroma. Numbness or a pins-and-needle tingling sensation on the side of the acoustic neuroma may also develop. In addition, patients can have difficulty forming tears and tasting certain foods.
