Tympanometry, or acoustic immitance testing, is a simple objective test of the ability of the middle ear to transmit sound waves across it. This test is usually abnormal with conductive hearing loss.

For basic screening, a conductive hearing loss can be identified using the Rinne test with a 256 Hz tuning fork. The Rinne test, in which a patient is asked to say whether a vibrating tuning fork is heard more loudly adjacent to the ear canal (air conduction) or touching the bine behind the ear (bone conduction), is negative indicating that bone conduction is more effective that air conduction. A normal, or positive, result, is when air conduction is more effective than bone conduction.

With a one-sided conductive component the combined use of both the Weber and Rinne tests is useful. If the Weber test is used, in which a vibrating tuning fork is touched to the midline of the forehead, the person will hear the sound more loudly in the affected ear because background noise does not mask the hearing on this side.

The following table compares sensorineural hearing loss to conductive:

This may include a blood or other sera test for inflammatory markers such as those for autoinflammatory diseases.

Differential testing is most useful when there is unilateral hearing loss, and distinguishes conductive from sensorineural loss. These are conducted with a low frequency tuning fork, usually 512 Hz, and contrast measures of air and bone conducted sound transmission.

- Weber test, in which a tuning fork is touched to the midline of the forehead, localizes to the normal ear in people with unilateral sensorineural hearing loss.

- Rinne test, which tests air conduction "vs." bone conduction is positive, because both bone and air conduction are reduced equally.

- less common Bing and Schwabach variants of the Rinne test.

- absolute bone conduction (ABC) test.

"Table 1". A table comparing sensorineural to conductive hearing loss

Other, more complex, tests of auditory function are required to distinguish the different types of hearing loss. Bone conduction thresholds can differentiate sensorineural hearing loss from conductive hearing loss. Other tests, such as oto-acoustic emissions, acoustic stapedial reflexes, speech audiometry and evoked response audiometry are needed to distinguish sensory, neural and auditory processing hearing impairments.

Direct examination of the external canal and tympanic membrane (ear drum) with an otoscope, a medical device inserted into the ear canal that uses light to examine the condition of the external ear and tympanic membrane, and

middle ear through the semi-translucent membrane.

A test administered by a medical doctor, otolaryngologist or audiologist of the tympanic membrane and middle ear function using a tympanometer, an air-pressure/sound wave instrument inserted into the ear canal. The result is a tympanogram showing ear canal volume, middle ear pressure and eardrum compliance. Normal middle ear function (Type A tympanogram) with a hearing loss may suggest presbycusis. Type B and Type C tympanograms indicate an abnormality inside the ear and therefore may have an additional affect on the hearing.

Imaging is usually not pursued in those with uncomplicated conductive hearing loss and characteristic clinical findings. Those with only conductive hearing loss are often treated medically or with surgery without imaging. The diagnosis may be unclear clinically in cases of sensorineural or mixed hearing loss and may become apparent only on imaging. Therefore, imaging is often performed when the hearing loss is sensorineural or mixed.

A high-resolution CT shows very subtle bone findings. However, CT is usually not needed prior to surgery.

Otosclerosis on CT can be graded using the grading system suggested by Symons and Fanning.

- Grade 1, solely fenestral;

- Grade 2, patchy localized cochlear disease (with or without fenestral involvement) to either the basal cochlear turn (grade 2A), or the middle/apical turns (grade 2B), or both the basal turn and the middle/apical turns (grade 2C); and

- Grade 3, diffuse confluent cochlear involvement (with or without fenestral involvement).

Treatment of otosclerosis can be understood basically under three heads : medical, surgical and amplification.

In case of infection or inflammation, blood or other body fluids may be submitted for laboratory analysis.

Hearing loss is generally measured by playing generated or recorded sounds, and determining whether the person can hear them. Hearing sensitivity varies according to the frequency of sounds. To take this into account, hearing sensitivity can be measured for a range of frequencies and plotted on an audiogram.

Another method for quantifying hearing loss is a speech-in-noise test. As the name implies, a speech-in-noise test gives an indication of how well one can understand speech in a noisy environment. A person with a hearing loss will often be less able to understand speech, especially in noisy conditions. This is especially true for people who have a sensorineural loss – which is by far the most common type of hearing loss. As such, speech-in-noise tests can provide valuable information about a person's hearing ability, and can be used to detect the presence of a sensorineural hearing loss. A recently developed digit-triple speech-in-noise test may be a more efficient screening test.

Otoacoustic emissions test is an objective hearing test that may be administered to toddlers and children too young to cooperate in a conventional hearing test. The test is also useful in older children and adults.

Auditory brainstem response testing is an electrophysiological test used to test for hearing deficits caused by pathology within the ear, the cochlear nerve and also within the brainstem. This test can be used to identify delay in the conduction of neural impulses due to tumours or inflammation but can also be an objective test of hearing thresholds. Other electrophysiological tests, such as cortical evoked responses, can look at the hearing pathway up to the level of the auditory cortex.

A child with a congenital hearing loss should begin receiving treatment before 6 months of age. Studies suggest that children treated this early are usually able to develop communication skills (using spoken or sign language) that are as good as those of hearing peers.

In the United States of America, because of a Federal law (the Individuals with Disabilities Education Act), children with a hearing loss between birth and 3 years of age have the right to receive interdisciplinary assessment and early intervention services at little or no cost. After age 3, early intervention and special education programs are provided through the public school system.

There are a number of treatment options available, and parents will need to decide which are most appropriate for their child. They will need to consider the child’s age, developmental level and personality, the severity of the hearing loss, as well as their own preferences. Ideally a team of experts including the child’s primary care provider, an otolaryngologist, a speech-language pathologist, audiologist and an educator will work closely with the parents to create an Individualized Family Service Plan. Treatment plans can be changed as the child gets older.

Children as young as 4 weeks of age can benefit from a hearing aid. These devices amplify sound, making it possible for many children to hear spoken words and develop language. However, some children with severe to profound hearing loss may not be able to hear enough sound, even with a hearing aid, to make speech audible. A behind-the-ear hearing aid is often recommended for young children because it is safer and more easily fitted and adjusted as the child grows as compared to one that fits within the ear.

Parents also will need to decide how their family and child are going to communicate. If the child is going to communicate orally (speech), s/he may need assistance learning listening skills and lip reading skills to help her/him understand what others are saying. Many children with hearing loss also need speech or language therapy.

A child also can learn to communicate using a form of sign language. In the United States of America, the type preferred by most deaf adults is American Sign Language (ASL), which has rules and grammar that is distinct from English. There are also several variations of sign language that can be used along with spoken English which are standard in English-speaking countries outside the United States.

There is also a visual model of spoken language called cued speech. Learning to lip read is very difficult because many sounds look the same on the lips. Cued speech enables young children with hearing loss to clearly see what is being said, and learn spoken languages with normal grammar and vocabulary. It clarifies lip reading using 8 hand shapes in 4 positions and usually takes less than 20 hours to learn the entire system.

Surgery may be recommended if a child has a permanent conductive hearing loss caused by malformations of the outer or middle ear, or by repeated ear infections. Although fluid in the middle ear usually results in only temporary hearing loss, chronic ear infection can cause a child to fall behind in language skills. In some cases, a doctor may suggest inserting a tube through the eardrum to allow the middle ear to drain. This procedure generally does not require an overnight hospital stay.

Surgery also may be an option for some children with severe to profound sensorineural hearing loss. A device called a cochlear implant can be surgically inserted in the inner ear of children as young as 12 months of age to stimulate hearing. The surgery requires a hospital stay of one to several days. With additional language and speech therapy, children with cochlear implants may learn to understand speech and speak reasonably well, but the amount of improvement is variable.

Once a child is diagnosed, the immediate and anticipated reaction of the parents and immediate family is one of the denial. Doctors or the audiologists need to counsel the family, help them cope with the situation and encourage them to look forward to solutions to overcome the problem. Often when the family is told about the excellent options available for a hearing impaired child, the chances of acceptance are much better. Once the family accepts the handicap, half the battle is over and rehabilitation can begin.

The type of intervention required depends on several factors. Chief among these is the degree of impairment. When a child has a fair degree of residual hearing, the correct intervention would be fitting "optimised" hearing aids. "Optimisation" means fitting the child with a hearing aid appropriate to its degree of deafness.

Today a variety of good quality hearing aids are available – analog or digital body worn (for small children) or ear level for older children. When fitting a hearing aid, a competent audiologist has to assess the child's residual hearing, look at the hearing aid's performance and fit the child with an appropriate instrument. Equally important is the ear mould, which has to be custom made to suit the shape of the child's ear.

If a child has profound or total deafness, the benefits of hearing aids are limited. Depending upon the level and type of hearing loss, cochlear implants may be used instead of hearing aids.

Other causes of congenital hearing loss that are not hereditary in nature include prenatal infections, illnesses, toxins consumed by the mother during pregnancy or other conditions occurring at the time of birth or shortly thereafter. These conditions typically cause sensorineural hearing loss ranging from mild to profound in degree.

Treatment is supportive and consists of management of manifestations. User of hearing aids and/or cochlear implant, suitable educational programs can be offered. Periodic surveillance is also important.

About 1 in 1,000 children in the United States is born with profound deafness. By age 9, about 3 in 1,000 children have hearing loss that affects the activities of daily living. More than half of these cases are caused by genetic factors. Most cases of genetic deafness (70% to 80%) are nonsyndromic; the remaining cases are caused by specific genetic syndromes. In adults, the chance of developing hearing loss increases with age; hearing loss affects half of all people older than 80 years.

Audiometry (measuring ability to hear sounds of a particular pitch) is usually abnormal, but the findings are not particularly specific and an audiogram is not sufficient to diagnose Pendred syndrome. A thyroid goitre may be present in the first decade and is usual towards the end of the second decade. MRI scanning of the inner ear usually shows widened or large vestibular aqueducts with enlarged endolymphatic sacs and may show abnormalities of the cochleae that is known as Mondini dysplasia. Genetic testing to identify the pendrin gene usually establishes the diagnosis. If the condition is suspected, a "perchlorate discharge test" is sometimes performed. This test is highly sensitive, but may also be abnormal in other thyroid conditions. If a goitre is present, thyroid function tests are performed to identify mild cases of thyroid dysfunction even if they are not yet causing symptoms.

Individuals with Nager syndrome typically have the malformations of the auricle, external auditory canal, and middle ear, including the ossicles. These malformations were found in 80% of individuals with Nager syndrome. Inner ear malformations, however, are not typically seen in this population. Middle ear disease is common among individuals with Nager syndrome. Chronic otitis media and Eustachian tube deformity can result in conductive hearing loss. For this reason, early detection and treatment for middle ear disease is crucial in this population. Sensorineural hearing loss is not a typical characteristic of Nager syndrome; however, a subset of individuals present with a mixed hearing loss, due to a progressive sensorineural component combined with the typical conductive hearing loss (Herrman "et al.", 2005).

Typically, testing is first done to determine the quality of hearing. This can be done as early as in the first two weeks with a BAER test (Brain Stem Auditory Response Test). At age 5–6, CT or CAT scans of the middle ear can be done to elucidate its development and clarify which patients are appropriate candidates for surgery to improve hearing. For younger individuals, this is done under sedation.

The hearing loss associated with congenital aural atresia is a conductive hearing loss—hearing loss caused by inefficient conduction of sound to the inner ear. Essentially, children with aural atresia have hearing loss because the sound cannot travel into the (usually) healthy inner ear—there is no ear canal, no eardrum, and the small ear bones (malleus/hammer, incus/anvil, and stapes/stirrup) are underdeveloped. "Usually" is in parentheses because rarely, a child with atresia also has a malformation of the inner ear leading to a sensorineural hearing loss (as many as 19% in one study). Sensorineural hearing loss is caused by a problem in the inner ear, the cochlea. Sensorineural hearing loss is not correctable by surgery, but properly fitted and adjusted hearing amplification (hearing aids) generally provide excellent rehabilitation for this hearing loss. If the hearing loss is severe to profound in both ears, the child may be a candidate for a cochlear implant (beyond the scope of this discussion).

Unilateral sensorineural hearing loss was not generally considered a serious disability by the medical establishment before the nineties; it was thought that the afflicted person was able to adjust to it from birth. In general, there are exceptional advantages to gain from an intervention to enable hearing in the microtic ear, especially in bilateral microtia. Children with untreated unilateral sensorineural hearing loss are more likely to have to repeat a grade in school and/or need supplemental services (e.g., FM system – see below) than their peers.

Children with unilateral sensorineural hearing loss often require years of speech therapy in order to learn how to enunciate and understand spoken language. What is truly unclear, and the subject of an ongoing research study, is the effect of unilateral conductive hearing loss (in children with unilateral aural atresia) on scholastic performance. If atresia surgery or some form of amplification is not used, special steps should be taken to ensure that the child is accessing and understanding all of the verbal information presented in school settings. Recommendations for improving a child's hearing in the academic setting include preferential seating in class, an FM system (the teacher wears a microphone, and the sound is transmitted to a speaker at the child's desk or to an ear bud or hearing aid the child wears), a bone-anchored hearing aid (BAHA), or conventional hearing aids. Age for BAHA implantation depends on whether the child is in Europe (18 months) or the US (age 5). Until then it is possible to fit a BAHA on a softband

It is important to note that not all children with aural atresia are candidates for atresia repair. Candidacy for atresia surgery is based on the hearing test (audiogram) and CT scan imaging. If a canal is built where one does not exist, minor complications can arise from the body's natural tendency to heal an open wound closed. Repairing aural atresia is a very detailed and complicated surgical procedure which requires an expert in atresia repair. While complications from this surgery can arise, the risk of complications is greatly reduced when using a highly experienced otologist. Atresia patients who opt for surgery will temporarily have the canal packed with gelatin sponge and silicone sheeting to prevent closure. The timing of ear canal reconstruction (canalplasty) depends on the type of external ear (Microtia) repair desired by the patient and family. Two surgical teams in the USA are currently able to reconstruct the canal at the same time as the external ear in a single surgical stage (one stage ear reconstruction).

In cases where a later surgical reconstruction of the external ear of the child might be possible, positioning of the BAHA implant is critical. It may be necessary to position the implant further back than usual to enable successful reconstructive surgery – but not so far as to compromise hearing performance. If the reconstruction is ultimately successful, it is easy to remove the percutaneous BAHA abutment. If the surgery is unsuccessful, the abutment can be replaced and the implant re-activated to restore hearing.

Auditory perception can improve with time.There seems to be a level of neuroplasticity that allows patients to recover the ability to perceive environmental and certain musical sounds. Patients presenting with cortical hearing loss and no other associated symptoms recover to a variable degree, depending on the size and type of the cerebral lesion. Patients whose symptoms include both motor deficits and aphasias often have larger lesions with an associated poorer prognosis in regard to functional status and recovery.

Cochlear or auditory brainstem implantation could also be treatment options. Electrical stimulation of the peripheral auditory system may result in improved sound perception or cortical remapping in patients with cortical deafness. However, hearing aids are an inappropriate answer for cases like these. Any auditory signal, regardless if has been amplified to normal or high intensities, is useless to a system unable to complete its processing. Ideally, patients should be directed toward resources to aid them in lip-reading, learning American Sign Language, as well as speech and occupational therapy. Patients should follow-up regularly to evaluate for any long-term recovery.

The age when outer ear surgery can be attempted depends upon the technique chosen. The earliest is 7 for Rib Cartilage Grafts. However, some surgeons recommend waiting until a later age, such as 8–10 when the ear is closer to adult size. External ear prostheses have been made for children as young as 5.

For auricular reconstruction, there are several different options:

1. "Rib Cartilage Graft Reconstruction:" This surgery may be performed by specialists in the technique. It involves sculpting the patient's own rib cartilage into the form of an ear. Because the cartilage is the patient's own living tissue, the reconstructed ear continues to grow as the child does. In order to be sure that the rib cage is large enough to provide the necessary donor tissue, some surgeons wait until the patient is 8 years of age; however, some surgeons with more experience with this technique may begin the surgery on a child aged six. The major advantage of this surgery is that the patient's own tissue is used for the reconstruction. This surgery varies from two to four stages depending on the surgeon's preferred method. A novel one stage ear reconstruction technique is performed by a few select surgeons. One team is able to reconstruct the entire external ear and ear canal in one operation.

2. "Reconstruct the ear using a polyethylene plastic implant (also called Medpor):" This is a 1–2 stage surgery that can start at age 3 and can be done as an outpatient without hospitalization. Using the porous framework, which allows the patient's tissue to grow into the material and the patient's own tissue flap, a new ear is constructed in a single surgery. A small second surgery is performed in 3–6 months if needed for minor adjustments. This surgery should only be performed by experts in the techniques involved. The use of porous polyethylene implants for ear reconstruction was initiated in the 1980s by Alexander Berghaus.

3. "Ear Prosthesis:" An auricular (ear) prosthesis is custom made by an anaplastologist to mirror the other ear. Prosthetic ears can appear very realistic. They require a few minutes of daily care. They are typically made of silicone, which is colored to match the surrounding skin and can be attached using either adhesive or with titanium screws inserted into the skull to which the prosthetic is attached with a magnetic or bar/clip type system. These screws are the same as the BAHA (bone anchored hearing aid) screws and can be placed simultaneously. The biggest advantage over any surgery is having a prosthetic ear that allows the affected ear to appear as normal as possible to the natural ear. The biggest disadvantage is the daily care involved and knowing that the prosthesis is not real.

The treatment will vary with the different grades, but the most common is a surgical repair. The surgical option is cosmetic reconstruction of the external ear's normal shape and repair of the ear canal. In less severe cases the reconstruction will be sufficient to restore hearing. In grades of anotia/microtia that affect the middle ear the surgery with the use of a Bone Anchored Hearing Aid (BAHA) will likely restore the hearing. The BAHA may be surgically implanted onto the skull which would allow for some hearing repair by conduction through the skull bone. "This allows sound vibrations to travel through bones in the head to the inner ear."

BAHA: An implantable hearing device. It is the only hearing aid device that works via direct bone conduction.

Individuals with hemifacial microsomia, also called oculoauriculo-vertebral spectrum, often have ear malformations. These malformations can be in the form of preauricular ear pits, complete absence of the auricle, stenosis or atresia of the external auditory canal, ossicular malformations, middle ear deformities, and incomplete pneumatization of the temporal bone. Rahbar "et al." (2001) found that 95% of individuals with this syndrome have an ear malformation of some type. In addition to ear malformations, a conductive hearing loss can be present, typically ranging from mild to severe. There are also reported cases of cochlear involvement and sensorineural hearing loss. Rahbar "et al." (2001) found that 86% of patients with Hemifacial Microsomia have a conductive hearing loss and 10% have a sensorineural hearing loss. There is no correlation between the severity of dysmorphic features and the degree of hearing loss, meaning individuals with mild malformations can have severely impaired hearing.

In cases where the causes are environmental, the treatment is to eliminate or reduce these causes first of all, and then to fit patients with a hearing aid, especially if they are elderly. When the loss is due to heredity, total deafness is often the end result. On the one hand, persons who experience gradual deterioration of their hearing are fortunate in that they have learned to speak. Ultimately the affected person may bridge communication problems by becoming skilled in sign language, speech-reading, using a hearing aid, or accepting elective surgery to use a prosthetic devices such as a cochlear implant.

No specific treatment exists for Pendred syndrome. Speech and language support and hearing aids are important. Cochlear implants may be needed if the hearing loss drops to severe to profound levels and can improve language skills. If thyroid hormone levels are decreased, thyroid hormone supplements may be required. Patients are advised to take precautions against head injury.

In some cases, the loss is extremely sudden and can be traced to specific diseases, such as meningitis, or to ototoxic medications, such as Gentamicin. In both cases, the final degree of loss varies. Some experience only partial loss, while others become profoundly deaf. Hearing aids and cochlear implants may be used to regain a sense of hearing, with different people experiencing differing degrees of success. It is possible that the affected person may need to rely on speech-reading and/or sign language for communication.

In most cases the loss is a long term degradation in hearing loss. Discrediting earlier notions of presbycusis, Rosen demonstrated that long term hearing loss is usually the product of chronic exposure to environmental noise in industrialized countries (Rosen, 1965). The U.S. Environmental Protection Agency has asserted the same sentiment and testified before the U.S. Congress that approximately 34 million Americans are exposed to noise pollution levels (mostly from roadway and aircraft noise) that expose humans to noise health effects including the risk of hearing loss (EPA, 1972).

Certain genetic conditions can also lead to post-lingual deafness. In contrast to genetic causes of pre-lingual deafness, which are frequently autosomal recessive, genetic causes of post-lingual deafness tend to be autosomal dominant.

It is important that the patient attend periodic follow-up checks, because even after careful microscopic surgical removal, cholesteatomas may recur. Such recurrence may arise many years, or even decades, after treatment.

A "residual cholesteatoma" may develop if the initial surgery failed to completely remove the original; residual cholesteatomas typically become evident within the first few years after the initial surgery.

A "recurrent cholesteatoma" is a new cholesteatoma that develops when the underlying causes of the initial cholesteatoma are still present. Such causes can include, for example, poor eustachian tube function, which results in retraction of the ear drum, and failure of the normal outward migration of skin.

In a retrospective study of 345 patients with middle ear cholesteatoma operated on by the same surgeon, the overall 5-year recurrence rate was 11.8%. In a different study with a mean follow-up period of 7.3 years, the recurrence rate was 12.3%, with the recurrence rate being higher in children than in adults.