Examination and diagnosis methods of common deafness

Tuning fork examination is the most commonly used method to identify the nature of deafness. A group of tuning forks with five octaves in C key are commonly used, and their vibration frequencies are 128, 256, 5 12, 1024, 2048Hz respectively. Attention during inspection: tap the upper part of the tuning fork arm1/3; The striking strength should be consistent, and it is not allowed to strike the table with force or hard objects to avoid overtones; When checking the air conduction, the plane of the 1/3 arm on the vibrating tuning fork should be consistent with the longitudinal axis of the external auditory canal, the same height as the opening of the external auditory canal, and about1cm away from the opening of the external auditory canal; When checking bone conduction, the bottom of the handle is placed on the skull surface; The vibrating tuning fork can't touch anything around it. Commonly used inspection methods are as follows:

1. Linner test

Also known as air-bone conduction contrast test, it is an examination method to compare the air-bone conduction of the same side. Take a tuning fork of C256, place it in the mastoid sinus area after vibration, and measure its bone conduction hearing. When you can't hear the sound, record its time, immediately move the tuning fork outside the external auditory canal 1cm, and measure its air conduction hearing. If you can still hear the sound, it means that air conduction is longer than bone conduction (AC >；); BC), which means Linnaeus test is positive (RT "+"). On the contrary, bone conduction takes longer than air conduction (BC & gtAC), which is called negative Linnaeus test (RT "-").

2. Weber test

Also known as bone conduction deviation test, compare the strength of bone conduction hearing in both ears. Take the handle of C256 or C5 12 vibrating tuning fork and place it in the center of forehead or head, so that patients can compare which ear is louder. If the binaural hearing is normal or the nature and degree of binaural hearing impairment are the same, the sound is in the middle, which is impartial for bone conduction. Because air conduction has the function of resisting bone conduction, when conductive deafness occurs, the air conduction of the affected ear is blocked and cannot resist bone conduction, which makes the bone conduction of the affected ear stronger than that of the healthy ear, and the sound tends to be biased towards the affected ear; When sensorineural hearing loss occurs, the sound of healthy ears is stronger because of the pathological changes of hearing organs in the affected ears, and the sound tends to be biased towards healthy ears. When recording, in addition to the text description, → or ← can indicate deviation, = can indicate no deviation.

3. Schwabach test

Also known as bone conduction contrast test, in order to compare the bone conduction time between normal people and patients, the vibrating C256 tuning fork handle base is alternately placed in the mastoid sinus area of patients and examiners for comparison, and the normal people are equal; If the patient's bone conduction time is longer than the normal ear, the Schwartz test (ST "+") is prolonged, which is conductive deafness; If it is shorter than the normal value, the bone conduction contrast test is shortened (ST "-"), which is sensorineural deafness.

4. Subjective listening test technology

It mainly includes pure tone hearing threshold test and speech test for adults, behavior test for children and speech test for children. We can test the hearing sensitivity and evaluate the communication ability in daily life through the patient's subjective reaction. Objective detection techniques mainly include acoustic immittance test, auditory brainstem response (ABR) and otoacoustic emission (OAE) test, 40Hz event-related potential and so on. Auditory steady-state evoked potential has the characteristics of rapidity, non-invasion, good frequency specificity, good correlation with behavioral hearing threshold, objective testing method and objective judgment of results. Modulation frequency >: at 60Hz, it is not affected by waking state, and it is an ideal quantitative diagnosis method for hearing loss of children, especially infants.

5. Image inspection

It mainly includes functional magnetic resonance imaging technology and positron emission tomography technology. Functional magnetic resonance imaging (fMRI) can observe the activity of the human brain in awake state, and can directly reflect the changes of brain function related to events. High spatial resolution, no radiation damage, and can be used for adults and children with sensorineural hearing loss. In recent years, SilentfMRI technology has become the first choice and main means to study the function of auditory conduction pathway, which is expected to provide new ideas for clinical diagnosis, treatment and prognosis evaluation. Positron emission tomography (PET) can detect human body function and diagnose diseases from gene, molecule and whole level earlier, more accurately, more quantitatively and objectively. [5-6]

diagnose

The medical history should be carefully asked; Check the external auditory canal and tympanic membrane; Carry out tuning fork examination and pure tone audiometry to understand the nature and degree of deafness. For children and uncooperative adults, subjective behavior audiometry and objective audiometry can also be carried out, such as acoustic impedance audiometry, auditory brainstem response audiometry and cochlear electrogram. Combined with clinical manifestations, a diagnosis can be made.

treat cordially

Treatment of conductive deafness and mixed deafness

Early active treatment of acute and chronic suppurative otitis media and secretory otitis media is an important measure to prevent conductive deafness. Tympanoplasty has a certain effect on improving hearing of conductive deafness. The application of total artificial ossicles and partial artificial ossicles obviously improved the hearing effect of tympanoplasty for conductive deafness. With the development of artificial hearing implantation technology, the application of implantable hearing AIDS, bone anchor hearing AIDS and vibrating sound bridge in recent years has opened up new treatment options for conductive deafness and mixed deafness.

Bone anchor hearing aid is an implantable bone conduction hearing system, which is suitable for conductive or mixed hearing impairment and unilateral deafness. The bone anchor hearing aid adopts the form of direct bone conduction. This method is different from the traditional air conduction and bone conduction hearing AIDS in many aspects. When a tiny titanium implant is fixed on the bone behind the ear, it will fuse with human bone. It takes about three months for adults to form bone fusion, and six months for children. Once the bone fusion is formed, a bridge can be fixed on the titanium implant, and then the speech processor can be clamped on it. When the voice processor detects the sound, it will transmit the sound directly to the inner ear through the bone. This process bypasses the outer ear and the middle ear.

Vibrating acoustic bridge is a kind of middle ear implant device, which is more widely used than other hearing AIDS. It is mainly suitable for adults and children with moderate and severe sensorineural deafness, conductive deafness and mixed deafness. Vibrating sound bridge is different from hearing aid, which simply amplifies sound, while vibrating sound bridge converts sound into mechanical vibration; Vibration acoustic bridge is also different from cochlear implant. It sends out electrical signals to stimulate nerve fibers, while vibration acoustic bridge produces mechanical vibration, which is transmitted to middle ear structure or directly to inner ear.

The language and other sound signals heard through the vibrating sound bridge are clear and sound quality is good. In a complex listening environment, people can communicate without barriers if there is a large background noise. You can also hear sounds with a slightly higher frequency, such as children's voices and violin playing. At the same time, after the vibration bridge is implanted, the external auditory canal of the patient is completely open, eliminating the blocking feeling and other discomfort caused by the closed auditory canal; It's also very comfortable and beautiful to wear. [7]

2. Treatment of sensorineural deafness and central deafness

For sensorineural deafness, the emphasis is on prevention, early detection and treatment. At present, the genetic diagnosis of deafness and newborn hearing screening in China have greatly improved the incidence of sensorineural deafness.

(1) Actively prevent and treat deafness caused by acute infectious diseases, do a good job in the prevention, isolation and treatment of infectious diseases, and enhance the resistance of the body (especially children).

(2) For the use of ototoxic drugs, the indications should be strictly controlled, and if there is poisoning, the drug should be stopped immediately, and vitamins and vasodilators should be used.

(3) According to the different causes and stages of the disease, different drugs can be used for comprehensive treatment, such as drugs to enhance neurotrophic and improve cochlear microcirculation, various vasodilators, biological products to promote metabolism, etc.

(4) With the development of electronic technology, computer technology, biomaterial science and biomedical engineering technology, since the end of last century, cochlear implants, vibrating acoustic bridges and bone-anchored hearing AIDS have been applied in clinic abroad. Cochlear implant is suitable for patients with severe to extremely severe sensorineural deafness; Cochlear implant is the only medical device that can restore hearing for deaf patients. Vibrating acoustic bridge and bone anchor hearing AIDS are suitable for patients with moderate and severe sensorineural deafness, conductive deafness and mixed deafness. The above-mentioned three types of implantable hearing devices cover almost all kinds of hearing recovery treatments for patients with different degrees of hearing loss, so that deaf patients with different degrees, even deaf patients, can recover to near normal hearing, so that deaf patients can enter normal schools and even communicate by telephone.

Cochlear implant requires patients to have enough auditory nerve residues, and stimulation electrodes will be inserted into the cochlea. If the patient's auditory nerve does not exist, such as the patient after acoustic neuroma resection, cochlear implant cannot be accepted. Auditory brainstem implantation can put the stimulation electrode on the patient's brainstem (cochlear nucleus), and the patient can still restore hearing. This technology has matured abroad, and there is no successful case report in China. Indications include bilateral acoustic neuroma, cochlear ossification, internal auditory canal stenosis and auditory nerve hypoplasia. These patients can recover their hearing after auditory brainstem implantation. It is reported that the speech perception ability of patients with auditory brainstem implantation is worse than that of patients with cochlear implant. [8]

refer to

1. Huang, Wang Jibao, edited by Kong. Practical otorhinolaryngology head and neck surgery. Beijing: People's Health Publishing House, 2007: 1005 ~ 1009.

2. Depp, Yu Fei and Kang Dongyang. Diagnostic methods and clinical application of mitochondrial DNA 1555 locus, GJB2 gene and SLC26A4 gene. Chinese journal of otorhinolaryngology head and neck surgery, 2005: 40, 769 ~ 773.

3. Sun Baochun, Depp. Classification of inner ear malformation in sensorineural deafness and its relationship with SLC26A4 and GJB2 genes. PLA Military Medical College of Continuing Education (doctoral thesis), 20 1 1: 05.

4.JacklerRK，LuxforWM，HouseWF。 Congenital malformation of inner ear: classification Basic embryonic development: laryngoscope,1987: 97 (Suppl 40): 2 ~14.

5. Han Demin. Clinical audiology: Journal of Audiology and Speech Pathology, 2007: 15, 1 ~ 3.

6. Zhai suoqiang. Clinical audiological characteristics of deafness: Chinese Journal of Otology, 20 1 1: 236 ~ 240.

7. Zhao Vibrating acoustic bridge implantation: Journal of Audiology and Speech Pathology, 20 1 1: 19, 394 ~ 395.

Wang Liang, Zhang Daoxing and Dong Mingmin. Clinical application of auditory brainstem implantation: Department of Otolaryngology, China Medical Abstracts, 2004: 145 ~ 148.