TESTs & Procedures
Testing hearing in animals involves several methods which is depends on the species, the animal's behavior, and the specific auditory issues being investigated.
These methods are often used in combination to provide a comprehensive assessment of an animal's hearing capabilities and identify any potential auditory issues.
Here are some common techniques:
Behavioral Tests
Startle Response: Observing the animal's reaction to sudden, loud noises. This can be a simple way to check for basic hearing ability.
Sound Localization: Assessing whether an animal can locate the source of a sound by observing head or ear movements in response to various sound sources.
Conditioned Response: Training an animal to respond to a sound (e.g., pressing a lever or moving to a certain area) to determine their ability to hear different frequencies and volumes.
Electrophysiological Tests
Brainstem Auditory Evoked Response (BAER): A non-invasive test that measures the electrical activity in the auditory nerve and brainstem in response to sound stimuli. This test specifically evaluates the auditory nerve pathways. It is commonly used in dogs, horses, and other animals to diagnose congenital or acquired hearing loss.
Otoacoustic Emissions (OAEs): This test measures sound waves produced by the inner ear (cochlea) in response to auditory stimuli. A small probe is placed in the animal's ear canal to detect these emissions. Absence or reduction of OAEs can indicate hearing loss.
Physical Examination Tests
Otoscopy: .Using an otoscope to visually inspect the ear canal and eardrum for obstructions, infections, or other abnormalities that could affect hearing.
Impedance Audiometry (Tympanometry): Measures the movement of the eardrum in response to changes in air pressure. This helps evaluate middle ear function and detect issues like fluid buildup or Eustachian tube dysfunction.
Observational and Owner Reports Tests
Behavioral Changes: Observing changes in behavior that may indicate hearing loss, such as lack of response to calls, changes in vocalization, or difficulty in locating sounds.
Owner Report: Gathering information from pet owners about their animal's hearing abilities and any noticeable changes. These methods are often used in combination to provide a comprehensive assessment of an animal's hearing capabilities and identify any potential auditory issues.
Advanced diagnostic techniques procedure
Brainstem Auditory Evoked Response (BEAR) test is a non-invasive test that measures the electrical activity in the auditory nerve and brainstem in response to sound stimuli. It is used for screening and diagnosis of hearing loss in canines and equines.
These testing skills are similar to those requires testing auditory function of human infant.
Procedure: For preparation, numbing cream is applied to 3 different areas where the electrodes will be placed (forehead, top of the head, behind ears, and neck). For animals, needle electrodes will be used instead of surface electrodes which are placed just under the surface of the skin.
There will be no pain or discomfort for animals. Insert transducers are placed in the ear to present auditory stimuli. The response to the sound is measured by electrodes and displays on the screen as a waveform.-The waveform morphology is different than the human due to anatomy and physiology differences.
We look for repeatable waves at a specific latency, but analysis is the same as human.
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