The voice is a basic tool for human communication. Voice can reflect a person’s personality, cultivation, temperament and health condition, as well as his or her emotions and inner world. The human vocal organ is like a musical instrument, which has three main parts: power part, vibration part and resonance part. Among the human vocal organs, the respiratory organs (including the lungs, diaphragm and abdominal muscles) are the dynamic part, the vocal cords in the larynx are the vibratory part, and the oral cavity, pharynx and nasal cavity are the resonant part. In addition, there is an occlusal part, which includes the lips, tongue and teeth. In recent years, with the increasing frequency of interpersonal communication, people’s demand for voice is getting higher and higher, and the prevalence of voice diseases is increasing year by year. This kind of voice disease not only affects the quality of life and work, but also endangers the life of patients in serious cases. Therefore, the public should have a basic knowledge about the diagnosis, treatment and prevention of voice diseases. 1. Common causes of voice diseases 1. Voice abuse, improper use of voice and bad habits: Voice abuse is one of the most common causes of voice diseases. For example, patients often speak in a noisy environment; they like to scream or use their voice without rest for a long time; the frequency of pronunciation is not appropriate. Bad habits include smoking, alcohol abuse, staying up late, etc. 2, infection and inflammation: upper respiratory infection, tonsillitis, laryngitis, sinusitis, bronchitis, etc. can affect vocalization due to downstream infection of the vocal cords, while the corresponding symptoms of the disease itself appear. Laryngologists should also be alert to special infections such as laryngeal tuberculosis; viral infections, the most common of which is laryngeal papilloma caused by human papillomavirus, can be seen in adults and infants; various fungal infections such as histoplasmosis, coccidioidomycosis, candidiasis and other fungal laryngitis can also affect the voice 3, systemic factors, many systemic diseases can also lead to voice problems, commonly in the following cases. Reflux laryngitis: According to statistics, the incidence of reflux laryngitis in patients with voice diseases is as high as 50%. This disease is mainly caused by a transient or persistent relaxation of the gastroesophageal sphincter from various causes, which leads to reflux of gastric contents and reaches the larynx causing inflammation. It can be a static reflux, i.e. the patient does not perceive acid reflux per se. Abnormal endocrine function: The voice is considered to be the second sex characteristic of a person. The voice is exceptionally sensitive to changes in the endocrine level of the body. Changes in sex hormones that cause voice changes are very common in clinical practice. For example, sex hormone levels have a significant effect on voice changes during the male voice change period and the female voice change during menstruation. Hypo- or hyperthyroidism can affect the fluid composition of the lamina propria of the vocal folds, causing changes in the volume and shape of the vocal folds, resulting in voice changes. In addition, abnormal levels of other hormones such as parathyroid, adrenal and pituitary glands can also cause vocal disorders, and elderly people over 65 years of age can also have voice changes due to hormone level changes that lead to voice atrophy. Neurogenic diseases: including Parkinson’s disease, various tremor diseases, and myasthenia gravis can affect vocal function. In addition, various other diseases cause paralysis of the nerves that innervate the vocal folds and lead to impaired motor function of the vocal folds. Psychogenic vocal disorders are most common in young women, who suddenly lose their voice after emotional stress or trauma, with normal vocal fold appearance. The vocal folds are normal in appearance. The vocal folds do not retract during verbal vocalization, but are in the external booth or the vocal folds are floating, and the vocal fissure is large and small. Trauma: Commonly there are dislocation of the cricoarytenoid joint and laryngeal fracture, etc. Second, the classification of voice diseases: 1, inflammatory diseases: common are acute laryngitis, chronic laryngitis, vocal fold inflammation and some specific infections such as laryngeal tuberculosis, laryngeal syphilis, etc. 2. Benign proliferative lesions of the vocal folds: These lesions are the most common lesions seen in voice clinics. The most common ones are vocal fold polyps, vocal fold nodules, vocal fold cysts, vocal fold edema, vocal fold sarcoidosis, etc. 3.Laryngeal neuromuscular dysfunction: such as retroglottic nerve palsy, supraglottic nerve palsy, spastic vocal disorder, severe muscle weakness, etc. 4.Vocal cord mechanical dyskinesia: the most common is cricoarytenoid dislocation. 5, laryngeal tumors: laryngeal papilloma and laryngeal hemangioma are common benign tumors, vocal fold white shift and vocal fold keratosis are common precancerous lesions, laryngeal vocal fold cancer and hypopharyngeal cancer are common malignant tumors of the larynx. 6. Psychogenic vocal disorders, such as hysterical loss of voice. Voice function evaluation and voice disease diagnosis Voice function evaluation mainly includes: evaluation of vocal fold vibration characteristics, subjective and objective assessment of articulation quality, assessment of laryngeal function of airflow dynamics, assessment of laryngeal neuromuscular electrical function, 24-hour PH monitoring of pharyngeal reflux, and imaging assessment, etc. These functional assessments are also necessary for voice disease diagnosis. 1. Evaluation of vocal fold vibration characteristics Vocal fold vibration to produce fundamental sounds is the basis of vocalization, and the vibration of vocal folds can reach 100-250 times per second. In the natural state, it is impossible for the human eye to distinguish such rapid movements. The biggest advantage of stroboscopy is that it uses the physics of stroboscopic light source instead of flat light to change the high-speed vibration of the vocal cords into a slow motion visible to the naked eye, thus allowing us to observe the microscopic lesions on the vocal cord mucosa. Through the stroboscope doctors can not only observe the morphological changes of the patient’s larynx, but also make early diagnosis of early vocal cord cancer, vocal cord paralysis, vocal cord leukoplakia, and heterosensitivity through the observation of vocal cord mucosal waves, vocal cord vibration amplitude, and other characteristics that are not available in ordinary electronic laryngoscopes. Also, due to the large magnification, it is possible to examine small mucosal lesions that are not visible with other laryngoscopes. It is also meaningful for voice assessment of singers. It also has the function of simulating high-speed photography and taking photos for permanent data preservation. 2. Subjective and objective assessment of voice quality Subjective auditory perception evaluation of the voice is one of the necessary methods to determine the degree of lesion and evaluate the effectiveness of treatment. In many cases voice abnormalities are often first detected through subjective auditory perception, prompting patients to seek medical attention. These abnormalities may be detected by the speaker himself or by others. Commonly used assessment methods internationally include the GRBAS classification proposed by Japanese scholars and the CAPE-V classification proposed by American scholars. Applying a trained ear for analysis is a basic skill that one must be proficient in as a voice doctor. Objective acoustic analysis of voice includes voice disorder index, range map, speech spectrogram, voice fatigue test, frequency perturbation and amplitude perturbation, noise test and other indicators to objectively evaluate voice quality. The acoustic analysis can be used to initially analyze whether there are pathological changes in pronunciation, whether one is using one’s appropriate pronunciation characteristics to pronounce the voice, and whether the voice contains more noise components. 3.Aerodynamic assessment Aerodynamic laryngeal function examination has been widely used in clinical and basic research of voice in foreign countries. People can change the articulatory characteristics of a person by changing the shape of the lips and the position of the larynx. However, the value of airflow into the larynx cannot be changed. Therefore, it is very important to measure the subglottal airflow characteristics when assessing voice function. The parameters to be measured often include: velar airflow, subglottal pressure, vocal pressure threshold, vocal airflow threshold, and velar airflow. The application of aerodynamic analysis and acoustic examination can provide a more objective and comprehensive evaluation of laryngeal function. Laryngomyography is a method of testing the electrical activity of the laryngeal muscles and their innervated nerves. It tests the electrophysiological activity of the laryngeal muscle during different physiological activities such as articulation, breathing and swallowing to determine the functional status of the laryngeal nerves and muscles. Vocal fold dyskinesia is often encountered in voice clinics. This type of dyskinesia can be caused by paralysis of the recurrent laryngeal nerve or by dislocation of the cricoarytenoid joint. The laryngeal electromyography is the gold standard for differentiating between the two. In laryngeal nerve paralysis, abnormal EMG manifestations such as fibrillation waves, positive sharp waves or regenerative potentials can be produced, while cricoarytenoid dislocation is normal. Laryngeal EMG can also provide a scientific basis for the diagnosis, treatment and prognosis of spasmodic vocal disorders and other laryngeal neuromuscular pathologies. It is also usually a gateway to the treatment of spasmodic dysphonia with local botulinum toxin injections. The laryngeal electromyography examination needs to be participated by experienced laryngologists for examination and judgment. 5.Other tests Laryngeal imaging helps to find the cause of vocal disorder and differential diagnosis; 24-hour PH monitoring of pharyngeal reflux can clarify whether there is gastropharyngeal reflux. According to the specific conditions of laryngeal lesions, laryngologists will give appropriate examination and evaluation to accurately diagnose voice disorders. IV. Treatment of voice diseases The treatment of voice diseases is based on comprehensive treatment, including: conservative medical treatment and surgical intervention. 1. Conservative medical treatment Conservative medical treatment is based on voice training and drug therapy. (1) The purpose of voice training is to correct incorrect vocal habits and methods, to regulate the patient’s voice and breathing on the basis of determining the range of voice, to make full use of the resonance of the chest, larynx, oropharynx, nasal cavity and skull, and to achieve the best results gradually through the auditory reflex, so that some patients with vocal disorders can regain normal pronunciation. Another core part of voice training is voice health care, which mainly includes reducing voice abuse, ensuring appropriate amount of water every day, and avoiding stimulation by chemical substances and other irritants. (2) According to the symptoms and characteristics of laryngeal lesions of patients with voice diseases, appropriate antibiotics, hormones, Chinese medicine and other symptomatic drugs can be given. For inflammatory infections, local nebulized inhalation therapy can be used. For laryngeal reflux disease, proton pump inhibitors can be given to control acid reflux in the larynx and improve pronunciation. 2.Surgical interventions For certain voice diseases, surgical means can be used to restore and improve the quality of pronunciation. The main areas that are developing rapidly include: voice microsurgery techniques, vocal cord injection and filling techniques and laryngeal frame surgery. (1) Voice microsurgery technique In the early 1990s, the concept of voice microsurgery was introduced based on the theory of stratification of vocal fold tissue, which has further expanded the precision and breadth of voice surgical treatment. Microsurgery is a surgical procedure to preserve the unique stratified tissue structure of the vocal folds under the microscope or endoscope using microscopic instruments or laser technology, with the aim of improving and restoring the voice function while removing the lesion. The main indications include: benign laryngeal proliferative lesions, benign laryngeal tumors, laryngeal amyloidosis, precancerous lesions and early vocal cord cancer, laryngeal stenosis, double vocal cord paralysis, vocal cord scar, vocal cord adhesions, vocal cord sulcus, etc. However, whether to choose surgical treatment should be evaluated comprehensively. For example, vocal fold nodules should be treated first by correcting the poor pronunciation habits, and surgery should be considered only if conservative treatment is ineffective. Children with vocal fold nodules should choose conservative treatment. Vocal fold sarcoidosis has many causative factors and is closely related to reflux laryngitis, so surgery is not the preferred treatment. Many voice diseases can be well treated and voice quality improved significantly by removing the diseased tissues through voice microsurgery techniques combined with conservative medical treatment. (2) Vocal fold injection and filling technique Vocal fold injection and filling technique refers to the injection or filling of autologous or allogeneic substances into different levels or gaps of the vocal folds to restore the vibration characteristics of the vocal folds, improve the closure of the vocal folds, and restore better voice and swallowing protection functions. Because of its simplicity, efficacy and minimal trauma, it has been widely used in recent years for the treatment of poor vocal fold closure. However, due to the easy absorption of autologous fat, the long-term effect is not satisfactory or several injections are needed to maintain good vocal fold closure. (D) Prevention of voice diseases Voice is an important tool for human communication, whether it is speaking, reciting, singing, or broadcasting, it needs to be used. However, some people have not received training about voice health care, and long-term wrong way of using voice causes voice diseases, which brings a lot of troubles to work and life, which requires people to do well in voice health care in daily life. 1. First of all, we should avoid some bad habits, such as: Avoid using voice continuously in noisy and dry harmful environment. Correct bad habits, such as smoking, drinking alcohol, drinking strong tea or coffee, and overexertion. Correcting poor articulation habits, including frequent throat clearing, coughing, whispering, yelling, crying and laughing, excessive talking, singing, speaking for long periods of time in inappropriate tones (e.g., some kindergarten teachers), and excessive talking or singing in the presence of upper respiratory tract infections. Learn to alleviate excessive psychological stress. 2. It is important to master some common health care voice training methods and keep the habit of voice health on a daily basis as in the case of fitness. Here are three practical training methods: (1) Breathing training: Most of the voice diseases are related to improper breathing. Abdominal breathing can improve the efficiency of breathing and can provide more adequate power for the vocal process. What is abdominal breathing? If the abdominal wall puffs up during inhalation and contracts during exhalation, the abdominal wall sinks, then the whole breathing process is powered by the abdomen, which completes a good abdominal breathing. Training methods: Practice blowing outward while contracting the abdomen to experience the synergy of abdominal wall movement and breathing. Perform rapid inhalation and slow exhalation to train the control of the exhalation process. Make sure that the main points of abdominal breathing are met. Breathing combined with pronunciation: you can pronounce /s/ during exhalation, pay attention to the duration of the pronunciation and record the duration of the pronunciation. Choose some texts to train reading aloud. Be careful to breathe in during pauses in the reading. (2) Reducing hard rising: Hard rising is very common among professional speakers. A hard rise is a sudden, strong, loud sound that is produced during vocalization. In this way, the airflow over-impacts the vocal cords and the larynx is easily fatigued and damaged. Correction should be done to coordinate the relationship between breathing and vocalization in time. Training method: Pronounce the /h/ sound or feel the airflow before you pronounce it. Practice some words that begin with the /h/ sound, such as “ha”, “hey”, etc. Practice words starting with vowel sounds such as “love”, “ah”, etc. (3) Yawning and sighing: Many voice disorders are caused by the muscles in the larynx being too “stuck” during pronunciation. In order to eliminate the muscle jam, you need to practice yawning and sighing. By opening the airway to the maximum, relaxing the pharyngeal constrictor and then contracting the hyoid bone upward, an inspiratory yawn can be produced. An expiratory yawn also involves widening the pharynx to its maximum extent to open the vocal tract. Many patients who use this method can experience what a comfortable and relaxed vocalization is. Training method: Yawn and exhale gently to make a comfortable sound. Pronounce /h/ or open-mouthed vowels, starting with one word per yawn up to four or five words. Pronounce /hah/ with a sigh, then a string of /h/ followed by the addition of low and medium vowels, noting that the vocalization should be comfortable, relaxed and soft. Experience the relaxed feeling of the mouth brought by this method, and eventually remember this relaxed vocalization and use it in your daily pronunciation. In conclusion, voice has an important meaning to people’s life, and the goodness of voice directly affects the ability to express language, especially for singing actors, announcers, teachers and people who often work with voice, such as ticket sellers, salesmen, public relations staff, etc. It is very important. A famous American linguist once said, “The appearance and voice of a person is the key to success in life. Moving talk is far better than the heavy cosmetic powdered appearance, it can show a person’s beautiful and true personality, it can make a normal man become exceptionally outstanding, can make a less attractive lady look very attractive.” It is clear that how to speak and use the voice is very important for everyone. So we must take care of it carefully, adjust it scientifically, and use it reasonably. Only in this way can we ensure that our voice is pleasant to the ear and keep our voice youthful forever.