Why should I wear hearing aids if my auditory brainstem response is normal?

Children with hearing loss may suffer from hearing loss or unclear hearing if hearing intervention is not timely, which will affect the improvement of their language and cognitive abilities. Generally, if infants and young children fail the early hearing screening, they will be tested in combination with the auditory brainstem response (ABR) later.

1. What is auditory brainstem response?

ABR is a relatively accurate objective audiometry method. The test is not affected by the patient's subjective will and state of consciousness and can be performed while the patient is asleep. Clinically, we will combine ABR with objective hearing testing for infants and children who cannot cooperate with subjective hearing tests. If the brainstem evoked potential is normal, it generally means that the hearing is normal and no hearing aids are needed. However, we will encounter some exceptions because the test results of ordinary ABR reflect the high-frequency threshold. If the hearing loss of low and medium frequencies is often ignored, it will lead to limited development of the child's language and cognitive abilities.

2. Basic information of the case Li XX, female, failed the otoacoustic emission test on the third day after birth. The ABR at 3 months old showed that the right ear was normal and the left ear was severely impaired. At that time, it was thought that the hearing of the right ear was normal, so no intervention was made and the left ear wore a hearing aid. At the age of 4, the behavioral audiometry results showed that the right ear had moderate hearing loss, but the child did not cooperate well at that time, so the ABR was rechecked, and it still showed that the right ear was normal, and the acoustic impedance compliance value of both ears was A (normal middle ear). The parents thought that all the examinations were normal and did not make further tests and interventions.

When the child was 5 years and 9 months old, his parents sent him to a rehabilitation center for speech therapy because of his poor speech clarity. A few months later, the rehabilitation teacher reported that the child's auditory recognition accuracy of single syllables and initials and finals was not high at a distance of one meter, and some syllables were difficult to correct, so an appointment was made for a behavioral audiometry examination.

Through basic assessment, it was initially judged that the child's intellectual development was at a medium level, but his language expression and cognitive abilities were obviously inconsistent with his actual age, his attention was not focused, and the pronunciation of related syllables such as bgkf was unclear. Under normal circumstances, simple unilateral deafness has little effect on daily language learning. Therefore, it is suspected that there may be problems with the hearing of the right ear. Considering the child's age and cognitive problems, we used the built-in audiometry of the hearing aid to test the child's hearing in the form of a game listening and playing. At that time, the cooperation was good, and the hearing threshold of both ears was initially obtained. After multiple behavioral audiometry, it was shown that the child's low-mid-frequency hearing loss was an average of 45-50dBHL, including an uphill audiogram of 25dBHL for 3000Hz-4000Hz hearing (Figure 1). The second retest of the right ear still showed a similar audiogram (Figure 2). The parents went to the hospital for a reexamination for the third time, and the results were similar after multiple behavioral audiometry (Figure 3). Imaging examination: No obvious abnormalities were found in the plain scan of the mastoid CT on both sides.

It can be seen from this that the previous ABR V wave threshold just happened to be displayed in the normal high-frequency range, but in fact the hearing of the low and medium frequencies is reduced. This is the main reason why young children cannot hear or cannot hear some syllables clearly, especially when the other person speaks at a low volume, it sounds very vague, which not only affects the clarity of children's speech, but also affects cognitive learning in life and classroom.

3. Situation after hearing intervention After the parents realized the problem of their child, they cooperated with the audiologist to select suitable hearing aids. The sound field assessment showed that the threshold of 250-4000Hz after hearing aid was around 25-30dBHL, which is close to normal hearing. The child said that he could hear very clearly after wearing the hearing aid. The parents also said that the child was willing to wear the hearing aid and was sensitive to small sounds of low and medium frequencies. More than a month later, the hearing was rechecked and the pronunciation problems that had existed before were reassessed. It was found that the bpgkf related sound energy could be self-corrected by emphasizing listening. After three months, the gk sound can be stably pronounced, and the pronunciation of bpf in sentences is unstable. The child is still undergoing rehabilitation treatment. The pronunciation of the child is stable and gradually improving.

The child did not use a hearing aid in his right ear at first because the ABR test was normal and the middle ear test was also normal, so the possible hearing loss in the low and medium frequencies was ignored, resulting in missed diagnosis. Therefore, we must strengthen behavioral audiometry and, if necessary, combine it with Tone-ABR (t-ABR for short, the stimulus sound is frequency-specific and can measure the results of frequencies such as 250Hz\500Hz\1000Hz\2000Hz\4000Hz) test to avoid similar situations as much as possible. In addition, parents should be especially reminded: If the child's language and cognitive development is slow in the later stage, it should be taken seriously, reviewed in time, and the audiologist should be cooperated with to do behavioral audiometry, soft voice test and other forms to verify the results, so as not to delay the child's language and cognitive development.