Audiometry or audiometry overview is an examination to understand the state of auditory function and diagnose auditory diseases by observing the response caused by sound. Listening can be checked by pure tone, noise, short tone or language (whisper, spoken language). , directly from the sound source or through instruments (headphones, speakers) to the tested ear. There are many methods of listening test, and the response caused by sound can be divided into two types: one is to observe the response of the examinee after subjective judgment, which is called subjective observation listening method; The other is to observe the reaction without subjective judgment and consciousness, which is called objective audiometry.
Subjectivity includes whispering test, stopwatch test, tuning fork test, pure tone audiometry (hearing threshold test, suprathreshold hearing test), language audiometry and some pseudo-deaf tests. Some of these methods are to observe the listening distance (the distance between the sound source and the tested ear), some are to observe the listening time (the length of listening), and some are to observe the auditory sensitivity. But no matter which method is adopted, it is based on the subjective judgment of the subject. Due to the differences of age, intelligence, education level, understanding ability and the influence of spirit and consciousness, the examination results are often not very accurate, or even impossible to be examined, such as infants, coma, deafness and so on. However, most of the above methods are simple and easy to operate, and are still commonly used in clinical hearing examination.
Objectively, it can be divided into four categories: unconditional reflex audiometry, conditioned reflex audiometry, impedance audiometry and electrical response audiometry. Unconditional reflex audiometry is to observe the changes of heart rhythm and breathing rhythm caused by sound, as well as physiological reactions such as turning head and blinking. For example, peripheral vascular response audiometry is used to observe the changes of finger blood volume; Observe and record the baby's physiological response to sound (screen diagram). Conditional reflex audiometry is to judge the listening state by establishing the conditioned reflex between sound and some physiological reaction, and then observing the change of this physiological reaction. For example, skin resistance audiometry is to establish conditioned reflex between sound and sweating, and then use the change of skin resistance when sweating to check hearing; Another example is scene matching audiometry, which uses children's interest in pictures or toys to establish a conditioned reflex between the sound * * * and pressing the button to light up the scenery, and then gradually reduces the intensity of the sound * * * to test children's hearing threshold. Impedance audiometry and electrical response audiometry are new objective audiometry methods developed in recent twenty or thirty years, which use the impedance phenomenon of the middle ear to sound waves and bioelectricity phenomena such as cochlea, brain stem or cortex to detect hearing (see "impedance audiometry" and "electrical response audiometry"). Objective audiometry does not need to be based on the subjective judgment of the subjects, and is not affected by age and consciousness, so the examination results are more accurate and reliable, especially for infant audiometry and the distinction between organic and non-organic deafness. However, most objective audiometry methods are complex and require special instruments and equipment, so they cannot be popularized at present. However, objective audiometry is the development direction of audiometry, which will be more perfect and widely developed in the future.
Note: Adult routine hearing examination includes: external auditory canal examination, pure tone audiometry and acoustic immittance test. Patients with hearing loss should be examined carefully. Deafness is a disease that seriously harms patients' physical and mental health and has a great influence on patients' daily life. Tuning fork examination is the most commonly used method to identify the nature of deafness. A set of five octave tuning forks in C mode is often used to detect hearing loss or deafness.