Tinnitus is a subjective sensation that cannot be tested when the patient subjectively hears sound without any external sound source stimulation. It is a subjective feeling of the patient, and tinnitus is a category of symptoms rather than a disease. Such as the sensation of monotonous or mixed loud sounds such as cicadas, buzzing and hissing in the ear. It does not include sound hallucinations and vibrating sounds from other parts of the body, such as vascular sounds and breathing sounds when the eustachian tube is open.
A. Etiology: Tinnitus is a symptom of many diseases involving the auditory system, and is the result of different pathological changes. There are two common classifications: one is the classification of the root hearing dysfunction site; the other is the etiological classification. The latter is more practical.
A root hearing dysfunction site classification
1. Conductive tinnitus is mostly caused by external middle ear diseases, and is low-frequency persistent or ergogenous tinnitus, mostly seen in tympanic membrane trauma and otitis media.
2. Sensorineural tinnitus is the most common type of neurological tinnitus, and the damage site is mostly located in the cochlea (see the blue snail-like structure in the figure, which is the only organ that perceives sound). It is commonly caused by age-related deafness, ototoxic drug tinnitus, Meniere’s disease, delayed membranous vagal effusion, etc. It is also seen in diseases such as exolymphatic fistula, inner ear infection, otosclerosis, etc. It is tinnitus in the general sense.
3. Central neural tinnitus is caused by lesions in the central auditory pathway such as the nerve from the cochlea and the brainstem afterwards. Poor response to masking. The tinnitus is caused by the lesion of the gray nerve part after the blue cochlea in the figure.
Etiological classification
1. Physiological tinnitus is mainly a body sound that appears in the skull. In a person with normal hearing, ① the humming sound of blood circulation and muscle tremors can be heard in a very quiet environment, and ② the sound produced by the Brownian motion of air on the tympanic membrane. ③The sound of blood vessels moving during strenuous exercise. ④Vascular murmur caused by compression of the temporal artery when the head is placed sideways on the pillow. (⑤) The clicking sound caused by the opening of the eustachian tube during swallowing. Most of these tinnitus do not require treatment. Strictly speaking, it is not considered tinnitus.
2. Pathophysiological tinnitus is caused by minor lesions in the cochlea, posterior cochlear nerve pathway and brainstem
(i) Spontaneous tinnitus Most people experience transient tinnitus that lasts for a few seconds, rarely more than 5 minutes.
(ii) Noise-induced tinnitus Most commonly occurs after exposure to loud noises (firecrackers, explosions) and lasts from a few seconds to several days
(iii) Drug-related tinnitus occurs after oral administration of certain ototoxic drugs and is mostly bilateral, with variable duration and may be persistent. It is mainly caused by damage to the cochlea. Tinnitus that is not accompanied by hearing loss is drug-related tinnitus, while those that are accompanied by hearing loss should be drug-related deafness.
(iv) Hematotoxic tinnitus Temporary or persistent tinnitus can be caused by toxemia caused by systemic infection.
3. Pathological tinnitus Refers to tinnitus caused by clear inner ear or brainstem lesions
(i) Body sound
(i) Regular twitching or vibration caused by palatal muscle, which can be heard by others except oneself.
②Breathing sound, a blowing-like sound synchronized with breathing heard when the eustachian tube is open.
(③) Vascular eruptive sounds produced during strenuous movement, rarely seen in arterial stenosis, kinetic aneurysm, arteriovenous fistula and atherosclerotic stenosis. This category is also not strictly tinnitus.
(ii) Tinnitus caused by external auditory canal and middle ear pathology Such as external ear canal cerumen, foreign body, otitis media, tympanic chamber tumor, etc.
(iii) It is caused by inflammation, poisoning, vascular and lymphatic vessels of the cochlea. The mechanism is the most complicated and is still not well studied. This type of tinnitus is exactly what we usually call tinnitus, and it is also the most common.
(iv) Neurogenic tinnitus caused by postcochlear auditory neuropathy, see inflammatory nerve fiber degeneration demyelination and nerve tumors, such as auditory neuroma.
(v) Tinnitus caused by vascular abnormalities, inflammation, and tumors in the brainstem and higher regions. This type is less common.
III. Treatment of tinnitus.
(i) Etiological treatment is theoretically the most ideal treatment method, but clinically it is mostly impossible to determine the cause, and sometimes the cause is determined but there is no treatment or treatment is extremely difficult, such as drug-related tinnitus. Only 5% of the diseases can be diagnosed and treated after the etiology, such as tinnitus caused by cerumen embolism, and the tinnitus disappears after removal of cerumen.
(ii) Some patients can be treated with medication, mainly to improve microcirculation and nerve nutrition, but in case of depression and anxiety, antidepressant and anxiety treatment is required.
(iii) Physical masking therapy, such as playing music to mask the sound of tinnitus, some patients may feel that their tinnitus is reduced under the noise environment, which is a masking effect.
(iv) Psychological treatment Through verbal or non-verbal communication, the psychological state of the patient can be changed to achieve certain therapeutic effects. Such as cognitive therapy, through psychological analysis, let patients recognize their unreasonable way of thinking and show them the right way to change the patient’s bad cognition in order to achieve the purpose of treatment. For example, patients should get used to their tinnitus, or treat it as a kind of musical sound, and not to deliberately experience and listen to it, and pay attention to diverting their attention when irritability occurs, etc. This treatment is a longer process, and if necessary, it should be combined with medication.
(v) Electrical stimulation therapy
(vi) Ultrasound irradiation therapy
(vii) Combination therapy for tinnitus There are many methods to treat tinnitus, and it is difficult to determine which treatment method is more effective, so clinically, the above treatment methods are often combined appropriately to treat tinnitus. The effectiveness of combined treatment is higher for women than for men. This method is also the most used in clinical practice.