Choice of hearing aid prescription formula

3.5 Choice of hearing aid prescription formula
For linearly amplified hearing aids, the NAL-RP formula has more research evidence than other formulas. From a large amount of clinical feedback, the NAL-RP formula has achieved great success, so it can be used with confidence in linear hearing aids.
Compared with the research volume of linear amplification, there are few clinical studies on the evaluation of non-linear prescriptions. Here, it is generally recommended that audiology professionals should choose the most credible rationale. Such as the NAL-NL1 formula or NAL-NL2, because the input strength of the 70dB SPL used in its prescription response is very similar to that used in the NAL-RP formula, there are also many reports that bias this formula. Children can choose the DSL [i / o] formula.
3.6 Medical Problems in Matching
Hearing loss is generally referred to as deafness, and those with less hearing loss are called hard of hearing. Deafness can be divided into organic deafness and functional deafness according to the nature of the disease; according to the time characteristics of onset, it can be divided into sudden deafness, progressive deafness and wave deafness; according to the lesion site, it can be divided into conductive deafness, sensory deafness Phononic deafness writes mixed deafness. Ear diseases that can cause hearing loss clinically and cause deafness are diverse. According to the different characteristics of deafness, the following medical issues must be paid attention to when selecting hearing aids in clinic.
1. Optional hearing aids for conductive deafness
To select hearing aids for patients with conductive deafness, in addition to understanding the causes and symptoms of conductive deafness, the characteristics of the disease, diagnosis and medical treatment methods, you must also understand the common characteristics of conductive hearing loss, and the attention of optional hearing aids matter. Conductive deafness is mainly caused by the outer and middle ears, which are obstacles to the transmission of sound pressure transformers and affect the transmission of sound waves.
Pure tone audiometry revealed normal bone conduction, decreased air conduction, and poor air-bone conduction. The air conductance curve is mostly uphill, with low frequency loss as the main cause, and the discomfort threshold (UCL) value is higher than that of ordinary people. If you perform a speech communication test, you find that the audibility is reduced and the speech perception valve is raised. However, if you put on a hearing aid and perform the same test and compare it with the previous one, you can find that the patient is very satisfied with the benefit of the hearing aid. Significantly improved communication capabilities. In addition, due to factors such as the clinical manifestations of people with conductive deafness and the relatively high UCL value tested, it is generally recommended to choose a linear amplifier for the hearing aid’s sound quality and listening effect.
Large hearing aids with peak clipping control, compression-limited hearing aids are also suitable. In the choice of hearing aid shape, they tend to prefer high-power behind-the-ear hearing aids. Of course, the choice of specific hearing aid types still needs to reach consensus between hearing professionals and hearing impaired patients. The following is a detailed introduction to the medical cognition, treatment and selection of hearing aids for several common clinical forms of conductive deafness.
(l) Conductive deafness due to congenital microtia and external ear canal atresia
For this type of patients, surgical treatment is preferred clinically. If you still have hearing loss, you can consider using bone conduction hearing aids (currently, head clip or implanted bone conduction hearing aids), BAHA or air conduction hearing aids.
(2) Conductive deafness caused by external ear canal embolism or foreign body blockage
The common clinical symptoms of these patients are ear canal occlusion and hearing loss. The degree of visual embolism and the status of foreign bodies are often complicated by ear bulging, ear pain, tinnitus, or dizziness. In severe cases, external ear canal infections occur. , Increased pain and other symptoms. Hearing loss caused by this type of condition is not recommended to choose a hearing aid for hearing compensation, but appropriate medical treatment should be performed according to the cause, such as the method of removing foreign matter from the device, the method of rinsing the external ear canal, etc.
(3) conductive deafness caused by secretory otitis media
Secretory otitis media is a non-purulent disease of the middle ear characterized by tympanic effusion and hearing loss. Middle ear effusion can be serous exudate or exudate, or mucus. Middle ear effusion is extremely viscous and jelly-like, which is called gel ear. This disease is more common in winter and spring, with acute and chronic points. Both children and adults can develop the disease, which is one of the common causes of deafness in children. Hearing loss in chronic secretory otitis media occurs more than unknowingly. Children often receive medical attention from parents due to their unresponsiveness to sound, inattention, and decline in academic performance. If one ear is diseased and the other ear is normal, it can be left undetected for a long time and only discovered during physical examination.
Patients with secretory otitis media are not recommended to choose hearing aids clinically, but should be actively treated. In particular, some patients who already have deafness and then suffer from acute and chronic secretory otitis media should be treated very early to prevent further hearing loss.
(4) Chronic suppurative otitis media with mastoid surgery and conductive deafness
Patients with chronic suppurative otitis media have stable hearing loss after surgery, and those with clear hearing compensation requirements can choose middle- and high-power behind-the-ear hearing aids. In the process of wearing hearing aids, you should always pay attention to keeping the ear canal open or dry, and often return to the hospital regularly. Those who have special requirements to select in-ear hearing aids should pay attention to the use of high-power hearing aids and keep the ear canal dry.
(5) Conductive deafness due to otosclerosis
Auricular otitis is a disease in which the dense lamellar bones of the labyrinth are replaced by sponge-like new bones rich in cells and blood vessels. In most cases, due to the involvement of the sacrum or cochlea, clinical or sensorineural hearing loss occurs. This disease is more common in young and middle-aged people, more women than men. Among them, if the ears are involved, the main treatment is surgery. Generally, the sacrum is partially or completely removed and then reconstructed with a “substitute”. Some people who are unwilling to undergo surgery but have increased hearing loss can choose a hearing aid, which works well, because patients generally show conductive or mixed deafness.
2. Hearing aids for patients with sensorineural hearing loss
Sensorineural deafness is a common clinical and complicated deafness. Even if the doctor makes the same diagnosis, it is often different in medical treatment or hearing aid selection due to individual differences. Because the specific types of sensorineural hearing loss are different, the clinical manifestations are often significantly different. Pure tone electrical audiometry test of sensorineural deafness found that air-bone conductance decreased synchronously and UCL value was low. Combined with the speech communication ability test, we found that speech intelligibility decreased. If they are tested with optional hearing aids, patients may complain that it is not obvious to benefit from hearing aids, and some speech is still heard
Unclear. Therefore, audiology professionals must comprehensively consider the clinical manifestations of patients with sensorineural hearing loss, and then select hearing aids. Generally speaking, if there is a decline in UCL value and a revival phenomenon, it is more appropriate to choose a non-linear amplification hearing aid. The use of broad motion love compression control can satisfy patients with sensorineural hearing loss. The following is a detailed introduction to the medical cognition, treatment and selection of hearing aids for several common clinical sensorineural deafness conditions.
There are many causes of sensorineural hearing loss, and the mechanisms of the lesions are different. At present, no specific medicine or method has been found in clinical medicine. The general principle of treatment is to actively treat the hearing loss or to partially restore the hearing loss, and try to preserve and make full use of the residual hearing. Commonly used drugs are mostly supportive and nutritional, such as neurotrophic agents, vasodilators, energy agents and so on. For the use of residual hearing, the current hearing aid technology has been widely used. It is mainly used to select various hearing aids or implant cochlea, and then perform systematic hearing and speech rehabilitation training.
(l) Congenital deafness
Congenital deafness refers to deafness that exists when a baby is born. In early infants and young children, hearing loss can be determined through otoacoustic emission meters, brainstem evoked potential tests, and behavioral audiometry. Patients with this type of congenital deafness currently have no particularly effective method to cure them in clinical medicine. Nowadays, more deaf children choose to perform hearing and speech rehabilitation training (optional hearing aids or installing electronic cochlea for hearing correction and scientific speech rehabilitation training), and have achieved very good results, which makes deaf children out of the silent world Be “deaf but not mute.” This is a very well-tested practice for pre-lingual deaf children.
effective method. The key to rehabilitation for deaf children is to “three early”, namely early detection, early diagnosis and early intervention. Hearing aid selection and rehabilitation training for deaf children should pay full attention to the physical and psychological characteristics of infants and young children. Before selecting and matching, we must first accurately judge the degree of hearing loss in children, and select hearing aids with different amplified power according to the degree, which are mainly behind-the-ear hearing aids, because children’s ear canals and auricles have not been formed, and custom hearing aids are not suitable. Optional hearing aids should also be customized ear molds, and often use soft ear molds. Optional hearing aids should be as digital and simple as possible, and have a high signal-to-noise ratio and safety. Consider young children during hearing aid adjustment
The ear canal cavity is smaller than an adult, and a magnification formula suitable for deaf children should be selected, and daily observations should be used to make corrections at any time.
(2) Deafness caused by infectious diseases
Infectious disease-induced deafness refers to sensorineural deafness caused or complicated by various acute and chronic infectious diseases, including unilateral or bilateral sensorineural deafness. The degree of deafness varies, and a small number of people with mild deafness can heal themselves. After the degree of deafness is stable, there is currently no clinically effective treatment, and hearing aids should be selected for hearing rehabilitation.
(3) Drug-induced deafness
Drug-induced deafness is common when the body is sensitive or overuses aminoglycoside antibiotics such as streptomycin, gentamicin, kanamycin, and minonomycin, or diuretics such as furosemide, diuretic acid, or lead , Mercury, carbon monoxide and other toxic substances. Deafness induced by drug-induced deafness is usually bilateral symmetrical sensorineural hearing loss. Symptoms begin during the medication period and appear after the drug is discontinued. Most of the deafness cannot be recovered, and hearing aids should be selected for hearing rehabilitation.
(4) Senile deafness
Senile deafness is a very common type of sensorineural hearing loss. The causes of senile deafness are various: it is related to the genetic aging genes, it is related to certain external environmental factors, and it is related to some common senile diseases, but in general it is still the result of physiological degradation. There is currently no effective treatment for senile deafness. This is the same as the treatment of tooth loss and presbyopia. They are problems that occur with age. Most treatments are difficult to work. With the deepening of deafness, the elderly are prone to communication difficulties and personality changes. Now more seniors are willing to choose hearing aids for hearing rehabilitation. This is also the most common type of customer in our hearing services. The hearing curve of this type of patients is more common in downhill or steep decline. Most of the clinical complaints are audible and inaudible. People with moderate hearing loss have better hearing aids, while some people who are deaf for a longer period of time or have a greater degree of deafness have poorer hearing aid results, and need to cooperate with a longer period of hearing rehabilitation training. The choice of hearing aids for the elderly is generally in-ear hearing aids or behind-the-ear hearing aids, which are more affordable and easy to use.
(5) Sudden Deafness
Sudden deafness refers to sensorineural deafness caused by sudden and instantaneous tinnitus, deafness, and rapid increase in hearing loss for unknown reasons. It is also called sudden deafness or idiopathic deafness. A small number of patients can gradually recover within 1 to 2 weeks after onset, and those who cannot recover in time will become permanent sensorineural hearing loss. Partial hearing recovery is not ideal and the loss is not serious. After hearing stability, hearing aid can be used for hearing compensation.
(6) Deafness caused by systemic diseases
Common systemic diseases that can cause deafness include hypertension and arteriosclerosis, nephritis or nephropathy, endemic cretinism, diabetes, hypothyroidism, blood disease, and immune system disorders. Both ears are involved, and different degrees of hearing impairment are shown with the disease. The treatment is mainly “the symptoms first, the root causes”. For some deaf people who have severely affected communication, it is recommended to choose hearing aids for hearing rehabilitation.
(7) Traumatic deafness
Traumatic deafness is more common due to head trauma, loud stimulation, electromagnetic radiation or long-term noise. Deafness is common in this group of patients with central or central hearing loss. Hearing loss is high and speech recognition rate is low. There are no special treatments in clinical practice, and hearing aids can be optional.