Tinnitus is a common clinical symptom with a high prevalence in the population, with about 13% to 18% of individuals experiencing tinnitus and (4 to 5)% seeking medical attention for it. Patients with tinnitus are usually accompanied by symptoms such as annoyance, difficulty sleeping, and difficulty concentrating, which can affect their daily life, work, and social interactions in severe cases. The mechanism of tinnitus is complex and has many causes. Abnormal electrical activity in any part of the auditory conduction pathway can cause tinnitus, and the persistent and annoying tinnitus is often influenced by psychological factors. The diagnosis and treatment of tinnitus is still a major challenge due to its subjective nature. However, with the change of the modern medical model, the traditional biomedical model has been transformed into a bio-social-psychological medical model. The treatment methods for tinnitus are becoming more and more diversified. In addition to drug treatment, there are masking methods, cognitive-behavioral therapy, biofeedback therapy and Chinese medicine treatment. Through comprehensive treatment, the patient’s tinnitus symptoms can disappear or be relieved. In this paper, we review the progress of clinical classification, mechanism of occurrence, diagnosis and treatment of tinnitus from the perspective of modern bio-social-psychological medical model.
1. Definition of tinnitus.
Tinnitus is a kind of sound sensation that exists subjectively in the ear when there is no external sound source stimulation, and it does not include sound hallucinations and body sounds. It does not include sound hallucinations or body sounds. Sound hallucinations are often manifested by hearing meaningful sounds, such as speech, music or sirens. Somato-sound refers to sounds coming from other parts of the body, such as pulsing blood vessels, the clacking sound of the palatopharyngeal muscles, and the breathing sound of an abnormal opening of the eustachian tube.
Tinnitus is not an independent disease, but a symptom accompanying many diseases. Ototoxic drug poisoning, senile deafness, sudden deafness, Meniere’s disease, auditory neuroma, otosclerosis and other otologic diseases can cause tinnitus, and some systemic diseases such as diabetes, hypertension and hyperlipidemia can also cause tinnitus.
2.Classification of tinnitus.
There are many ways to classify tinnitus, and the more meaningful clinical classification is based on the cause and the site of hearing dysfunction: conductive tinnitus, sensorineural tinnitus, and central tinnitus. Sensorineural tinnitus can be subdivided into cochlear tinnitus and neural tinnitus.
Associative band motion tinnitus (synkinetic, tinnitus) is a newly reported rare type of tinnitus. Synkinetic tinnitus is a more frequent sequelae of facial palsy. It is a more common sequelae of facial palsy. Associative tinnitus refers to the occurrence of other-perceived tinnitus during the voluntary movement of some facial muscles, probably due to the regeneration of the degenerated facial nerve with misdirected growth and innervation.
3. Mechanism of tinnitus.
At present, it is believed that tinnitus is an auditory disorder phenomenon, which may be caused by abnormal discharge of any link of the auditory conduction pathway. The mechanism of tinnitus generation includes both peripheral and central parts. In addition, some recent studies suggest that psychological factors also play an important role in the process of tinnitus generation, and abnormal neural activity in the non-auditory system, especially the limbic system related to emotion, can also lead to tinnitus.
Tinnitus can occur in association with cochlear injury, which may lead to synchronous depolarization of sensory cell synapses and abnormal synchronous firing of auditory nerve fibers. This abnormal synchronization can disrupt the temporal and spatial distribution of normal neural auditory signals, which can lead to abnormal auditory perception and produce tinnitus.
Jastreboff et al. proposed a neurophysiological model of tinnitus based on neurophysiological and psychological principles. Abnormal neuronal activity in the auditory system is first perceived at the lower levels of the auditory system, and this signal is further reinforced by subcortical centers and transmitted to the auditory cortex as a “sound”. –tinnitus is perceived, which is then evaluated by the center to produce the corresponding tinnitus loudness and boredom.
In addition, Moller, AR found similarities between tinnitus and chronic pain by summarizing some common features of both. , they are both subjective sensations, peripheral nerve (auditory or sensory nerve) severance often does not eliminate tinnitus or pain symptoms, central activity is involved in the production of both, and peripheral structural stimulation (acoustic masking stimulation or peripheral nerve electrical stimulation) is effective in some patients with tinnitus or chronic pain. sahley, TL et al. found opioid-like substance release in patients with subjective tinnitus, cochlear N-methyl-D aspartate receptors were enhanced, suggesting that their interaction plays a role in the production of tinnitus.
4. Diagnosis of tinnitus.
Based on the patient’s chief complaint and medical history, the diagnosis of tinnitus is relatively easy, but it is still very difficult to find an objective basis for detection and etiology in clinical practice. Through detailed investigation and evaluation of tinnitus patients with necessary auxiliary examinations, tinnitus caused by body sound and systemic diseases are excluded. Imaging of the temporal bone and/or cranial brain can rule out organic pathologies such as vascular malformations, auditory neuromas, and otosclerosis.
There is less objective evidence of tinnitus, and the significance of conventional audiometric methods in patients with tinnitus is less clear. Subjective observation of auditory findings (tinnitus matching, etc.) does not provide a strong objective basis for tinnitus.
In recent years, with the development of modern functional brain imaging techniques (e.g., MEG, PET, MRI, etc.), new possibilities for objective detection of tinnitus have been introduced. Using positron emission tomography (PET), it was found that local cerebral blood flow (rCBF) was accelerated in the left parietal-temporal auditory cortex of tinnitus patients, and the radiotracer 18F-labeled deoxyglucose (18F-FDG) indicated active metabolism in the left auditory cortex and was not related to the lateralization of tinnitus. This suggests a central involvement of tinnitus, which provides a new objective basis for tinnitus.
In addition, because of the obvious subjective characteristics of tinnitus, studies have shown that patients with chronic severe tinnitus have obvious psychological disorders. A tinnitus questionnaire (tinnitus, questionnaire, TQ) can correctly evaluate the emotional state of patients, the degree of their hearing difficulties and their tolerance of tinnitus, and can also be used to assess the situation after tinnitus treatment.
5.Treatment of tinnitus.
For the treatment of tinnitus, the first step should be to distinguish the cause of tinnitus, if it is caused by body sound, correct the cause of body sound, and if it is accompanied by systemic diseases, treat other diseases at the same time. Some cases have reported that for vascular pulsatile tinnitus, super-selective arterial embolization using digital subtraction angiography (DSA) can completely relieve the patient’s severe tinnitus symptoms.
For intractable subjective tinnitus of unknown cause, treatment remains a major challenge due to its obvious subjective features and influence by psychosocial factors. Statistics show that long-term tinnitus can affect patients’ quality of life, and the longer the tinnitus lasts, the greater the impact on patients’ quality of life. Therefore, an aggressive attitude should be taken towards the treatment of tinnitus.
With the change of modern medical model, the traditional biomedical model has been transformed into a bio-social-psychological medical model, and the treatment methods for tinnitus are becoming more and more diversified, including masking therapy, cognitive-behavioral therapy, biofeedback therapy and Chinese medicine, in addition to drug therapy. Through comprehensive treatment, the patient’s tinnitus symptoms can disappear or be effectively relieved.
(1). Pharmacological treatment.
Pharmacological treatment of tinnitus includes treatment of the underlying disease and symptomatic treatment of tinnitus. Symptomatic treatment includes vasodilators, anticonvulsants, local anesthetics, neurotrophic drugs, etc. The efficacy is not very certain. A recent study has treated subjective tinnitus with the antidepressant amitriptyline, and although tinnitus symptoms were still present in patients in the treatment group, they were significantly less self-conscious and tolerable than in the control group. In addition, studies with large samples have shown that Ginkgo biloba extracts EGb and 761 have therapeutic effects on tinnitus. Although they cannot prevent the occurrence of tinnitus and shorten its duration, early intervention therapy can significantly improve the prognosis of tinnitus patients.
(2) Masking therapy.
Masking method (masking, therapy) for tinnitus is the use of external acoustic stimulation by tinnitus masking therapy instrument to inhibit the spontaneous excitation enhancement activity of the cochlea or auditory nerve and inhibit the central nerve pathway above the lesion. The masking method works both ipsilaterally and contralaterally, and the masking sound can be adjusted to match the frequency spectrum and loudness of the tinnitus to achieve the masking purpose. Studies have concluded that the masking method has an efficiency of more than 75%, is easy to implement and has no side effects, so it is a more ideal tinnitus treatment method.
(3) Psychotherapy.
The psychological treatment of tinnitus mainly includes cognitive, behavioral, therapy and biofeedback, therapy. By changing tinnitus patients’ awareness of their tinnitus symptoms, the negative impact of tinnitus on them is minimized so that they can tolerate the presence of tinnitus well, and research studies with large samples have shown that psychotherapy is effective.
Tinnitus, retraining, therapy (TRT) is a new treatment method proposed by Jastreboff, in which tinnitus patients are given emotional and behavioral retraining through various means to modify their perceptions and reactions to tinnitus, and to improve the impact of tinnitus on their lives, work and social life. symptoms, with an approximate rate of up to 80% reported.
(4), Other.
There are reports of attempts to treat persistent tinnitus with deep brain electrical stimulation (deep, brain, stimulation, DBS), and it is believed that some tinnitus patients may be caused by abnormal central electrical activity at one or several loci.
In addition, there are also reports of tinnitus treatment by Chinese medicine, such as herbal prescriptions, acupuncture or acupuncture plus acupuncture point injection, etc., but the specific efficacy has yet to be further studied.
6. Experimental studies on animal models of tinnitus.
Research on tinnitus has been difficult. The newly established behavioral model of tinnitus in animals provides a powerful way to study tinnitus and provides a new ideal model for evaluating the effectiveness of tinnitus drug treatment.
In conclusion, tinnitus is a common clinical symptom with a high prevalence in the population, which can seriously affect patients’ daily life, work and social interaction. The mechanism of tinnitus is complex and may be caused by abnormal electrical activity in a part of the auditory conduction pathway, and is often influenced by social and psychological factors. Idiopathic tinnitus is a kind of psychosomatic disease. With the establishment of modern bio-social-psychological medical model, the treatment of tinnitus is becoming more and more diversified, and the patient’s tinnitus symptoms can disappear or be relieved through comprehensive treatment such as medication, masking therapy, cognitive-behavioral therapy, biofeedback therapy and Chinese medicine.