Hearing tests

Hearing assessment at F&A Medical Center

Medical history

Assessment begins with questions about the hearing problem, when it started and whether one or both ears are affected. Relevant details include noise exposure, ear infections or surgery, medication, dizziness or tinnitus, pregnancy and birth history for children, and hearing loss in the family.

Initial examination

The ENT specialist examines the ears and may use tuning-fork tests to obtain an initial indication of the type of hearing loss. More detailed testing may be carried out by an ENT clinician, audiology professional or trained assistant. Sounds of different pitches and levels are presented to determine what the patient can hear.

Types of hearing loss

1. Conductive hearing loss: sound is not transmitted efficiently through the outer or middle ear. Causes include impacted earwax, a perforated or scarred eardrum, middle-ear fluid, chronic middle-ear disease and problems with the ossicles such as otosclerosis.
2. Sensorineural hearing loss: the cochlea or auditory nerve is affected. Sound may be both quieter and less clear. Causes include ageing, noise exposure, genetic factors, infection, some medicines and disorders affecting the auditory nerve or brain.
3. Mixed hearing loss: conductive and sensorineural components are both present.

Tests for adults

Pure-tone audiometry: Through headphones and sometimes a bone vibrator, the patient responds to tones at different frequencies. The softest sounds heard are plotted on an audiogram. Comparing air and bone conduction helps identify the type of loss.

Speech audiometry: Words are presented at different levels to measure speech detection and recognition. Results help explain communication difficulties and may contribute to decisions about hearing aids, although benefit also depends on daily needs and fitting.

Tympanometry: A soft probe changes air pressure in the ear canal and measures movement of the eardrum. It can help detect middle-ear fluid, eardrum problems or Eustachian-tube dysfunction. Acoustic reflexes may be measured at the same time.

Tests for children

Testing is adapted to developmental age:

• Behavioural observation: an observer looks for consistent responses to sound in very young babies, although objective tests are often also needed.
• Visual reinforcement audiometry: a correct turn toward a sound is rewarded with a light or animation.
• Play audiometry: usually from about three years, the child completes a simple game action whenever a sound is heard.
• Paediatric speech testing: the child identifies words or points to pictures to show what was understood.

Objective and specialist tests

• Otoacoustic emissions (OAE): a small probe records sounds produced by healthy outer hair cells in the cochlea. The test is quick and is widely used in newborn screening and other assessments. A pass does not assess every part of the hearing pathway.
• Auditory brainstem response (ABR/BERA): electrodes record electrical responses from the auditory nerve and brainstem after sounds are played. It is useful when reliable behavioural results cannot be obtained or when a neural problem is suspected. Young children may need natural sleep, sedation or anaesthesia according to the test and specialist centre.

Referral to an audiology centre

Complex paediatric testing, implant assessment, detailed rehabilitation or unexplained results may require referral to a specialist audiology centre, sometimes in an academic hospital. The clinician combines all results with the history and examination before recommending treatment.