By combining both subjective and objective hearing tests, a comprehensive cross-validation can be established to diagnose the location, nature, and degree of hearing loss deaf children more comprehensively and accurately.
In the hearing management work for young deaf children, rehabilitation teachers need to understand the common subjective and objective hearing test methods and their interpretation the results, while also observing the hearing condition of children in their daily teaching activities. Only in this way can they provide more accurate feedback and suggestions to audiologists and parents, the children’s hearing in the best possible condition and laying a solid foundation for rehabilitation teaching.
- Definition
Psychoacoustics: Audiometry that requires subjective response from subjects to the stimulus sound.
Objective audiometry:ometry that does not require the subjective cooperation of subjects during the test.
- Category
Psychoacoustics: Pure tone audiometry (behavior observation audiometry, visual reinforcement audiometry, play audiometry), speech audiometry
Objective audiometry: Tympanometry, otoac emission, auditory brainstem evoked potential, multi-frequency steady-state evoked potential.
- Content
1.Subjective audiometry
01 Behavioral observation audometry (BOA)
(1) Infants within 6 months of age are usually tested for subjective hearing responses using the method of auditory behavior observation reaction audi (BOA);
(2) The use of sound-producing toys (drums/wooden fish/whistles, etc.) or electronic oscillators to infants and young children, observing auditory responses (such as stopping sucking when hearing a sound, eye movement, turning the eyes towards the sound source, crying loudly, etc.) obtain subjective hearing responses.
02 Visual reinforcement audiometry (VRA)
(1) It is commonly used in clinical practice for hearing tests of children within age range of 7 months to 2.5 years;
(2) The test subject is first conditioned to respond to the sound stimulus by turning towards a flashing toy rewards him, and then a conditioned response is established, and then the child’s hearing threshold is determined by observing the child’s response to sound by turning his head.
03 Play audiometry (PA)
(1) It is commonly used clinically for children aged 2.5 to 6 years with certain understanding ability;
(2) Through an interesting game, the child is taught to respond to sound, such as placing objects according to sound, sound puzzle, etc., and can actively participate in, so as to obtain the child’s threshold for sound.
This test requires that the child’s ability to operate can complete similar actions such as building blocks, rings etc., and the existing cognitive ability can understand the test requirements.
04 Pure tone audiometry
(1) Pure tone audiometry is a standardized behavioral response audiometry to test hearing acuity, including air conduction (AC) hearing threshold and bone conduction (BC) hearing threshold tests.
It reflects the hearing level the smallest sound that the testee can hear at each test frequency in a quiet environment, to understand whether the hearing is normal or not, as well as the location, degree nature of hearing loss, and as the basis for diagnosis and treatment.
(2) Conductive hearing loss: bone conduction is normal, air conduction is reduced, air- conduction difference > 10 dB HL;
(3) Sensorineural hearing loss: both air and bone conduction decrease, air conduction initially decreases at high frequencies, frequencies also decrease in the late stage, air-bone conduction difference < 10 dB HL;
(4) Mixed hearing loss: conductive and sensorineural loss exist simultaneously, air and bone conduction results are both > 20 dB HL, and the difference between the two is ≥ 15 dB HL.
05 audiometry
(1) It is a method of testing and judging the ability of the testee to understand and identify speech by using speech sounds as test signals;
(2) Strictly speaking, speech audiometry is an audiological test method that uses speech (standard) samples as test signals and checks the speech discrimination and speech ability of the testee through hearing AIDS that meet the standards;
(3) The results of speech audiometry are used to compare and verify the pure tone threshold, the speech recognition ability between the two ears, and help determine whether the patient is suitable for using hearing AIDS or cochlear implants, or to compare the performance of users with different equipment and after fitting;
(4) Speech audiometry includes: speech detection threshold (SDT) – the minimum speech level required for the testee to detect 0% of the speech signal;
Speech recognition threshold (SRT) – the minimum speech level required for the testee to understand 50% of the speech;
Speech recognition rate – the percentage of correct identification of the tested words by the testee’s tested ear, which is a commonly used method of speech audi.
2.Objective Audiometry
01 Tympanometry
(1) A method to detect the function of the middle ear transmission system and the brainstem auditory pathway by testing the acoustic impedance or acoustic admittance of the middle ear to understand the functional status of the middle ear;
(2) The common clinical tympanogram types of the middle ear are: Type A, Type B, Type C.
Type A: Normal type;
Type B: Flat type, suggesting that the tympanic membrane and middle ear system are not active, such as middle ear effusion, probe earwax obstruction, etc.;
Type C: Negative pressure tympanum type, suggesting that the middle ear is in a negative pressure state, and the common causes are mostly blocked eustachian tubes.
02 Otoacoustic Emission (OAE)
(1) One of the most commonly used methods for newborn hearing screening, the first hearing test done within 48 hours of the child’s birth;
(2) It is an audio energy that is generated in the cochlea, conducted through the ossicular chain and tympanic membrane, and released into the outer ear canal. It detects the function of the inner ear hair cells to determine the hair cells’ feedback to sound;
(3) It is easily affected by the functional status of the outer ear and middle ear. For example, the presence of foreign bodies in the outer ear canal, earwax, etc., will affect the accuracy of the results;
(4) When the hearing loss ≥ 40 dB, OAE cannot be detected.
03 Auditory Brainstem Evoked Potentials (ABR)
(1) A method to detect the integrity of the auditory nerve. It is a relatively objective hearing and brainstem function examination technique;
(2) Auditory evoked potentials are a series of signal waveforms recorded on the top of the skull after sound stimulation from the outside world. Through various analyses, it can reflect the physiological processes and pathological phenomena of the auditory nerve and auditory pathway, and can be used to detect early hearing damage or organic lesions of the auditory conduction pathway;
(3) Prolongation or disappearance of wave I latency usually indicates lesions of the inner ear;
(4) If wave I is normal, wave III latency is prolonged or disappeared, or the intervals of I-V and III-V are prolonged, it is preliminarily determined that the lesion site is behind the cochlea;
(5) Prolongation or disappearance of wave V latency is most common in acoustic neuroma clinically, and other lesions behind the cochlea can also cause characteristic changes in wave V.
04 Auditory Steady-State Response (ASSR)
(1) Performed during sleep. This is an electric potential response elicited by a continuous, i.e., steady-state sound stimulus of multiple frequencies that is recorded through the scalp, and it can make a judgment on the hearing condition of multiple frequencies at one time;
(2) The ASSR hearing threshold is higher than the pure tone hearing threshold, with a difference of 10-20 dB;
(3) In individuals with normal hearing and mild hearing loss, the difference between the ASSR hearing threshold and the pure tone hearing threshold is within 20 dB;
(4) In individuals with moderate hearing loss, the difference between the two is within 10 dB;
(5) In individuals with severe to profound hearing loss, the difference between the two is <5 dB;
(6) The heavier the hearing loss, the smaller the difference between ASSR and pure tone hearing threshold, and the higher the accuracy of estimating the pure tone hearing threshold with ASSR.


