When babies are small, it is difficult to determine whether they hear well or not, which is why any warning sign (such as the child not turning his head when you call him, not babbling, not upset by any loud noise and responding only to auditory stimuli ), it is best to take him to the pediatrician to evaluate if he needs to do any tests. In this case, and depending on the child's age, these are the hearing tests that you would have to detect hearing loss.
The hearing tests They are nothing more than methods that we apply doctors, technicians and therapists with training to measure hearing and are generally requested to make a diagnosis of hearing loss. According to the World Health Organization, hearing loss is defined as the loss of the ability to hear, either total or partial.
These measurements can be made from birth and this applies to both term and premature children, since embryologically the structures of the ear begin their base formation between the third and fifth week of gestation until 20 weeks, where later a process of maturation in brain structures through the process of myelination.
Myelination is an important process that consists of coating the axons (part of nerve cells or neurons) with a white substance that protects them and helps in the transmission of information.
To understand the measurement, we must know that hearing contemplates a pathway that passes through various structures within our body, which include (described in a simple way): inner ear, spinal cord (which is in the spinal column), connecting structures between the medulla and the brain, others that are at the base of the brain and those that are in the brain itself.
Having said this, we must compare, among the existing tests, which ones are adapted to the different age groups and for this we will describe the most frequently used by specialists and the scope of each one.
- Otoacoustic Emissions (OAE for its acronym in English)
It is a test that measures the response of the inner ear to sound. It is one of the tests most used in newborns and young infants because it is not very invasive, it can be done with the baby or the child awake, it is even taken in several countries as a mandatory screening test for hearing loss, practicing it even for a few hours of life.
However, as described above, it is a test that only measures a part of the auditory pathway, so if it is negative or NO PASS (as it is mostly reported), more specialized tests must be carried out. It provides quantitative and qualitative measurement and although it is practiced in newborns and young infants, it can be used in older children, since emissions from the inner ear can be perceived even in adolescents.
- Auditory evoked potentials
It is a test that collects the changes in the brain's auditory waves in the face of a sound stimulus and estimates the degree of electrical activity in the brain, so, unlike the previous one, if it evaluates all the elements (so far discovered) of the auditory pathway .
However, this test is generally indicated in infants older than 6 months and some document that even after one year of age, since it depends (in part) on the myelination process. Another limitation that it has is that it must be performed mostly under sedation, since the child must remain calm, giving a wide margin of objectivity in its result. If the baby was premature, it should be done taking into account the corrected age, not the chronological one. Provides quantitative measurement.
It is a subjective (behavioral) test that is used to evaluate the patient's current hearing, passing tonal (tone) or vocal (voice) sound stimuli. This is a test for older children, because it takes their active participation to carry it out and have confidence in its result.
There are evaluators who can practice it in children of approximately 3 years (previous training), although others prefer that they are older than 5 years, since they must remain a reasonable time in a booth paying attention to various instructions. No sedation is required, it is done with the child awake. Provides quantitative measurement.
Also known as the audiological test with tuning forks or Weber test, it is one where instruments called tuning forks are placed that, depending on their size, emit a sound with high or low frequencies to which the patient is asked if they listen or not. It is also practiced in older children (over 3 years or so) because we depend on their understanding and attention to perform it.
As you will see, there are several alternatives, the point is that your doctor should provide you with the one that best suits your baby's age and requirements.
You can read more articles similar to 4 hearing tests to detect hearing loss according to the child's age, in the On-Site Ear Care category.