Hearing Disorders

Diagnosis

Audiogram test

At Mayo Clinic, physicians specializing in hearing disorders (otologists) conduct a medical interview and physical examination of patients with potential hearing problems. Master's-trained hearing specialists called audiologists assist in the evaluation. Patients are given a battery of tests to confirm the cause of the hearing loss.

A number of tests are available to discover the nature of a hearing difficulty and to help determine effective treatments. The tests include:

Basic audiogram: determines the patient's hearing ability relative to normal adult hearing levels to determine if there is a hearing loss, where it occurs and its type or classification. This information is critical to determine if medical or surgical intervention is possible or if hearing aids may help. Ways to compensate for hearing loss may also be discussed during this session.

Tympanometry: assesses the operational status of the middle ear, which consists of the eardrum and three small bones that connect the eardrum to the inner ear. Middle-ear blockages or malfunctions often can be treated medically or surgically.

Stapedial reflexes and reflex decay: also evaluates the auditory nerve's ability to transmit hearing signals to the brain. Blockages along this pathway would indicate the need for further medical consultation.

Auditory brain-stem response (ABR) testing: measures electrical nerve impulses that carry the sound from the inner ear to the brain. Electrodes are placed in the ear canal and on the head, and short clicking sounds are transmitted. The audiologist can determine how sound is transmitted to the brain and if nerve impulses are blocked or interrupted.

TEN (threshold equalizing noise) test: determines if a patient has pitch regions in the inner ear that no longer respond to sound stimulation, thus creating "dead zones." Information about any nonfunctional regions of the inner ear can help to determine how to adjust hearing aids and how much they can improve hearing.

SIN (sentence-in-noise) test: evaluates the ability to understand conversational speech in the presence of background noise and compare the performance to that of normal listeners. Helps determine possible benefit from hearing aid use in noisy situations and what type of hearing aid circuitry might be needed.

Otoacoustic emissions: evaluates the functioning of the outer hair cells in the inner ear. Otoacoustic emissions are acoustic signals generated by the normal inner ear, either in the absence of acoustic stimulation (spontaneous emissions) or in response to acoustic stimulation (acoustically-evoked emissions). These emissions can be measured by placing a microphone in the ear canal opening and analyzing the signals obtained.