Audiometric testing procedures are used to diagnose hearing disorders.These tests include:
- Sound threshold audiometry – air and bone conduction to distinguish disorders of the inner ear (consisting of: Cochlea (cochlea) and the organ of equilibrium/referring to: sound sensation disorder) or the middle ear (referring to: sound conduction disorder)[Age-related hearing loss (presbycusis): symmetrical impairment of hearing with sloping in the higher hearing frequencies]
- Impedance measurement – measurement of the acoustic impedance of the eardrum (part of the sound waves reflected by the eardrum). The resistance changes with the tension of the eardrum and is a measure of the mobility of the eardrum.
- Distortion products of otoacoustic emissions (DPOAE) – inner ear function testing.
- Speech audiometry – examination of hearing in terms of perception and intelligibility of speech.
- Dichotic speech test – testing of central auditory processing in adults and children (from about 5 years).
- Binaural Masking Level Difference (BMLD) – detection of disorders of the central auditory pathway.
These tests can be used to determine whether age-related hearing loss is due more to changes in the hair cells of the inner ear or to neurodegenerative changes in the central auditory pathway. In age-related hearing loss, a combined disorder of hair cells (= sound perception disorder) and central auditory pathway (= sound processing disorder) is present in about half of the cases.
Optional medical device diagnostics – depending on the results of the history, physical examination, laboratory diagnostics and obligatory medical device diagnostics – for differential diagnostic clarification.
- X-ray of the skull – if Paget’s disease is suspected.
- Computed tomography of the skull (cranial CT, cranial CT or cCT).
- Magnetic resonance imaging of the skull (cranial MRI, cranial MRI or cMRI) – e.g., suspected acoustic neuroma, multiple sclerosis.
Which of the two methods is used depends on the exact location of the suspected damage and the availability of the methods:
- CCT mainly to examine the middle ear and the mastoid (mastoid process).
- CMRI mainly for the examination of the inner ear as well as the auditory nerve.
Following audiometric test procedures depending on the type of hearing loss.
| Method | Conductive hearing loss | Sensorineural hearing loss | Neural hearing loss | Central hearing loss |
| Whisper test | + | + | ||
| Tuning fork test | + | + | ||
| Hearing range determination | + | + | + | |
| Pure tone audiogram | + | + | + | + |
| Speech audiogram | + | + | + | |
| Otoacoustic emissions | + | |||
| Suprathreshold testing methods | + | + | ||
| Listener fatigue test | + | + | ||
| Electrical response audiometry | + | + |
More hints
- Measurement of retinal vessels (retinal vasculature): wider retinal venules (venous section of capillaries) and narrower retinal arterioles (arterial section of capillaries) were associated with hearing loss at middle age in one study. The wider retinal venules were associated with poorer hearing as early as the average age of 11 years.
