Early symptoms are easily overlooked, thus making diagnosis a challenge. There usually are symptoms, however, indicating the possibility of an acoustic neuroma. The first symptom in 90% of those with a tumor is a reduction in hearing in one ear, often accompanied by ringing in the ear called tinnitus. The loss of hearing is usually subtle and worsens slowly, although occasionally a sudden loss of hearing can occur. There may be a feeling of fullness in the affected ear. These early symptoms are sometimes mistaken for normal changes of aging, or attributed to noise exposure earlier in life and therefore the diagnosis is often delayed.
Since the balance portion of the eighth nerve is where the tumor arises, unsteadiness and balance problems or even vertigo (the feeling like the world is spinning), may occur during the growth of the tumor. The remainder of the balance system sometimes compensates for this loss, and, in some cases, no imbalance will be noticed. Larger tumors can press on the trigeminal nerve, causing facial numbness and tingling - constantly or intermittently. Tumor related increase of intracranial pressure may cause headaches, clumsy gait and mental confusion. This can be a life-threatening complication requiring urgent treatment.
Even though the facial nerve (the nerve that moves the face) may be compressed by the tumor, it is unusual for patients to experience weakness or paralysis of the face from acoustic neuromas - although this may occasionally occur.